Dụng Cụ Chỉnh Hình Và Chân Tay Giả Trong Phục Hồi Chức Năng (Ấn Bản Thứ 3)

Orthotics   Prosthetics
REHABILITATION

THIRD EDITION
Orthotics Prosthetics
Michelle M. Lusardi, PT, DPT, PhD
Professor Emerita
Department of Physical Th erapy & Human Movement Science
College of Health Professions
Sacred Heart University
Fairfi eld, CT
Milagros “Millee” Jorge, PT, MA, EdD
Professor and Dean
Langston University
School of Physical Th erapy
Langston, OK
Caroline Nielsen, BA, MA, Ph.D
Health Care, Education and Research Consultant
Bonita Springs, FL
Former Associate Professor and Director
Graduate Program in Allied Health
University of Connecticut
Storrs, CT

REHABILITATION

3251 Riverport Lane
St. Louis, Missouri 63043
ORTHOTICS & PROSTHETICS IN REHABILITATION, THIRD EDITION
978-1-4377-1936-9
Copyright © 2013, 2007, 2000 by Saunders, an imprint of Elsevier Inc.
No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including ­photocopying,
recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek
­permission, further information about the Publisher's permissions policies and our arrangements with organizations such as the Copyright
Clearance Center and the Copyright Licensing Agency, can be found at our website:
This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein).
Notices
Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in
research methods, professional practices, or medical treatment may become necessary.
Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information,
­methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety
and the safety of others, including parties for whom they have a professional responsibility.
With respect to any drug or pharmaceutical products identified, readers are advised to check the most current information provided
(i) on procedures featured or (ii) by the manufacturer of each product to be administered, to verify the recommended dose or formula, the
method and duration of administration, and contraindications. It is the responsibility of practitioners, relying on their own experience and
knowledge of their patients, to make diagnoses, to determine dosages and the best treatment for each individual patient, and to take all
appropriate safety precautions.
To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/
or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods,
­products, instructions, or ideas contained in the material herein.
978-1-4377-1936-9
Vice President: Linda Duncan
Content Manager: Kathy Falk
Senior Content Development Specialist: Christie M. Hart
Publishing Services Manager: Julie Eddy
Senior Project Manager: Andrea Campbell
Design Direction: Ashley Eberts
Printed in the United States of America
Last digit is the print number:  9  8  7  6  5  4  3  2  1

Dedication
To Lawrence Mario Lusardi
my husband and best friend
“To love someone deeply gives you strength. Being loved by
someone deeply gives you courage.”—Lao Tzu
M.M.L.
To Mitchell B. Horowitz
In thanksgiving for our wonderful married life together
and in memory of my beloved brother William Jorge.
“The way to love anything is to realize that it may be lost.”—G.K.
Chesterton
M.J.
To Svend Woge Nielsen
A true partner who nourishes my spirit and achievements with
his constant understanding and belief in me.
C.C.N.

vi
Elizabeth Ames, MD
Associate Professor, Residency Program Director, and
Coordinator of Orthopedic Curriculum
Dept. of Orthopaedics & Rehabilitation
UVM College of Medicine
Burlington, Vermont
Attending Surgeon
Dept. of Orthopaedics, Spine Institute
of New England
Fletcher Allen Health Care
Burlington, Vermont
Mark A. Anderson , PT, PhD, ATC
Professor
Department of Rehabilitation Sciences
University of Oklahoma Health Sciences Center
Oklahoma City, Oklahoma
Adjunct Professor
Health and Exercise Science
University of Oklahoma
Norman, Oklahoma
Noelle M. Austin , MS PT CHT
CJ Education & Cosulting LLC
Woodbridge, Connecticut
Certified Hand Therapist
ProPT
The Orthopaedic Group
Hamden, Connecticut
Ed Ayyappa , MS, CPO, FAAOP
Prosthetic Clinical Manager
Southern California Region
U.S. Department of Veteran Affairs
Health Care System
Long Beach, California
William J. Barringer , MS, CO
Department of Orthopedic Surgery
and Rehabilitation
University of Oklahoma
Oklahoma City, Oklahoma
Jennifer M. Bottomley , PT, MS, PhD
HEARTH–Homes for Elders at Risk Through Homes
Board of Directors, HEARTH
President, International Physical Therapists working with
Older People/WCPT
Adjunct Faculty
MGH Institute of Health Care Professions, Program
in Physical Therapy
Adjunct Faculty
Simmons College Program in Physical Therapy
Independent Educator and Geriatric Rehabilitation
Consultant
Boston, Massachusetts
Donna M. Bowers , PT, MPH, PCS
Clinical Associate Professor
Department of Physical Therapy
and Human Movement Science
Sacred Heart University
Fairfield, Connecticut
Kaia Busch, BS
Hanger Prosthetics and Orthotics
Seattle, Washington
Kevin Carroll , MS, CP, FAAOP
Vice President of Prosthetics
Hanger Prosthetics and Orthotics
Orlando, Florida
Joshua Carter , MD
Clinical Instructor
Orthopaedics and Rehabilitation Residency
Programs
South Burlington, Vermont
Mark D. Charlson, MD
Assistant Professor
Orthopaedics & Rehabilitation
University of Vermont College of Medicine
Burlington, Vermont
Kevin K. Chui, PT, DPT, PhD, GCS, OCS
Associate Professor
Department of Physical Therapy and
Human Movement Science
College of Health Professions
Sacred Heart University
Fairfield, Connecticut
Contributors

Contributors
vii
Jeff Coppage, MD
Department of Orthopaedic Surgery and Rehabilitation
University of Vermont
Burlington, Vermont
Dana Craig, BS
Health System Specialist
Prosthetic Service Line, VISN 22
Dept. of Veterans Affairs
Long Beach, California
Barbara A. Crane, PhD
Assistant Professor
Physical Therapy Program
Department of Rehabilitation Sciences
University of Hartford
West Hartford, Connecticut
Carol P. Dionne, PT, DPT, PhD, OCS, Cert MDT
Association Professor
Department of Rehabilitation Sciences
University of Oklahoma Health Sciences Center
Oklahoma City, Oklahoma 73126-0901
Joan E. Edelstein, MA, PT, FISPO, CPed
Special Lecturer
Program in Physical Therapy
Columbia University
New York, New York
Juan C. Garbalosa, PT, PhD
Clinical Associate Professor of Physical Therapy
Quinnipac University
Hamden, Connecticut
Marylynn Jacobs, OTRL/C, CHT
Partner
Attain Therapy and Fitness
East Longmeadow, Massachusetts
Milagros Jorge, PT, MA, EdD
Director, Post-Professional DPT Program
Dean, School of Physical Therapy
Former
Langston University
Langston, Oklahoma
Carolyn B. Kelly, PT
Department of Rehabilitation
Hartford Hospital
Hartford, Connecticut
Anthony E. “Toby” Kinney, DPT, OCS, MBA
Clinical Assistant Professor/Associate ACCE
Physical Therapy & Rehabilitation Science
University of Montana
Missoula, Montana
David A. Knapp, BSME, MAEd
Practice Manager
Hanger Prosthetics and Orthotics
North Haven, Connecticut
Adjunct Faculty
College of Education
Department of Nursing and Health Professions
University of Hartford
Hartford, Connecticut
Clinical Instructor
Orthotics and Prosthetics
Newington Certificate Program
Newington, Connecticut
Géza F. Kogler, PhD, CO
Research Scientist
Clinical Biomechanics Laborator
School of Applied Physiology
Georgia Institute of Technology
Atlanta, Georgia
Donald S. Kowalsky, PT, EdD
Associate Professor and Chair
Department of Physical Therapy
School of Health Sciences
Quinnipiac University
Hamden, Connecticut
Michelle M. Lusardi, PT, DPT, PhD
Professor Emerita
Department of Physical Therapy & Human
Movement Science
College of Health Professions
Sacred Heart University
Fairfield, Connecticut
Edward Mahoney, PT, DPT, CWS
Assistant Professor
Physical Therapy, Program
School of Health Professions
Louisiana State University Health Sciences Center
Shreveport
Shreveport, Louisiana
John W. Michael, MEd, CPO, FISPO, FAAOP
President
CPO Servies, Inc.
Portage, Indiana
Olfat Mohammed, PhD, PT
Professor and Graduate Advisor
Department of Physical Therapy
California State University–Long Beach
Long Beach, California

viii
Contributors
Caroline Nielsen, BA, MA, Ph.D
Health Care, Education and Research Consultant
Bonita Springs, FL
Former Associate Professor and Director
Graduate Program in Allied Health
University of Connecticut
Storrs, Connecticut
Roberta Nole, MA, PT, CPed
President
Stride Orthotics, Inc.
Middlebary, Connecticut
Judith Pepe, MD
Senior Associate Director, Surgical Critical Care Surgery
Hartford Hospital
Hartford, Connecticut
Associate Professor of Surgery
University of Connecticut Medical Cehter
Farmington, Connecticut
Elicia Pollard, PT, PhD
Assistant Professor
School of Physical Therapy
Langston University
Langston, Oklahoma
Richard A. Psonak, MS, CPO, FAAOP
Director
Division of Prosthetics and Orthotics
Assistant Professor
Department of Orthopedics and Rehabilitation
School of Medicine
University of Mississippi
Medical Center
Jackson, Mississippi
John Rheinstein, CP, FAAOP
Hanger Prosthetics and Orthotics
New York, New York
Julie D. Ries, PT, PhD
Associate Professor
Department of Physical Therapy
Malek School of Health Professions
Marymount University
Arlington, Virginia
Melvin L. Stills, CO(E), HFISPO
New Virginia, Iowa
John Thompson, CO
Hanger Prosthetics and Orthotics
Oklahoma City, Oklahoma
Victor G. Vaughan, PT, DPT, MS, OCS
Clinical Manager
Sacred Heart Sports Medicine and Rehabilitation Centers
Fairfield, Connecticut
Clinical Instructor
Department of Physical Therapy and Human
Movement Science
College of Health Professions
Sacred Heart University
Fairfield, Connecticut
Scott Ward, PT, PhD
Professor and Chair
Department of Physical Therapy
University of Utah
Salt Lake City, Utah
Ellen Wetherbee, DPT, OCS
Associate Professor and Academic Coordinator
of Clinical Education
Physical Therapy Program
Department of Rehabilitation Sciences
University of Hartford
West Hartford, Connecticut
Margaret Wise, OTR, CHT, CCM, CVE
Director
Upper Extremity Specialists, Inc.
Dallas, Texas
Rita A. Wong, PT, EdD, FAPTA
Professor and Chair
Department of Physical Therapy
Malek School of Health Professions
Marymount University
Arlington, Virginia
Christopher K. Wong, PhD
Assistant Professor of Clinical Physical Therapy
Program in Physical Therapy
Columbia University
New York, New York
Heather N. Worden, MSOP, BSME, CP
Associate Professor
Loma Linda University
Entry Level Masters in Orthotics & Prosthetics
Loma Linda, California
Certified Prosthetist
VAMC
Long Beach, California
National Va Prosthetic Gait Lab
Long Beach, California
John R. Zenie, MBA, CPO
Guilford, Connecticut

ix
The challenges facing health professionals who are dedicated
to providing effective and efficient, evidence-based, rehabi­
litation care to individuals with conditions affecting their
ability to engage in essential daily activities and participate
in meaningful roles are many. These challenges include the
ever more rapidly advancing technology that tests our ability
to remain up to date about available prosthetic and orthotic
options, expectations for productivity in practice reflected
in the very real time constraints of daily patient care, and
the need to be good stewards of the health care dollar while
at the same time providing the best orthosis or prosthesis,
and associated rehabilitation care so that the individual
can meet his or her personal goals when using the device.
Clearly, optimum care for these individuals and their family
requires the combined expertise of health professionals from
many different disciplines. The complexity of the health
care delivery and reimbursement systems, at times, may
make communication and collaboration problematic. We
hope that this work addressed this complexity by providing
information from the perspectives of many members of the
rehabilitation team.
There have been incredible technical advances since
publica­tion of the second edition of this text, as evidenced
by incorporation of stance-control knee units in knee ankle
foot orthoses, the development of effective neuroprostheses
as alternatives to traditional ankle foot orthoses, and the
widespread adoption of microchip-enhanced knee unit
in transfemoral prostheses. Military personnel surviving
significant musculoskeletal and neuromuscular wounds
or limb amputation in Operation Iraqi Freedom and
Operation Enduring Freedom in Afghanistan have challen­
ged expectations about what it is possible to accomplish
while wearing a prosthesis, and prompted significant effort
in research and development. The sacrifices of the service
men and woman during war will have a positive long-term
effect for all persons living with amputation or needing
an orthosis for function and meaningful participation in
activities of daily living. We are grateful for their military
service, and appreciate the catalyst that their injuries and
losses have been to research and development in the fields
of prosthetics, orthotics, and rehabilitation.
The goal of this edition of Orthotics and Prosthetics in
Rehabilitation is to present best available evidence for entry-
level physical therapy and orthotic/prosthetic students
exploring options, and to provide a positive model of
clinical decision-making in the context of multidisciplinary
and interdisciplinary care. We also intend the text to be
a comprehensive and accessible reference for practicing
clinicians; a resource for their person-centered examination,
evaluation, intervention planning, and outcome assessment.
Our contributors are professionals from the fields of orthotics
and prosthetics, physical and occupational therapy, and
medicine and surgery. We present this text as an example of
the value of collaborative and interdisciplinary patient care.
Each contributor has carefully researched the developments
in technology, examination, and intervention for the revised
or new chapter presented in this third edition. We have
incorporated concepts and language of the World Health
Organization's International Classification of Functioning,
Disability, and Health (ICF) to enhance communication
across disciplines. We have updated the case examples,
posing sequential relevant questions to provoke discussion of
alternatives as a model of effective clinical decision-making.
We have opted not to “answer” the questions posed, on the
grounds that the general principles we present in the text
must be adapted appropriately to meet individual needs,
daring readers to work through the problem-solving process
and debate the pros and cons of the various options with
their peers. We seek to provide opportunity to “practice” the
process of evidence-based clinical decision making, rather
than present an absolute prescription or plan of care. We hope
that this approach will provide a workable model, prompting
reader to critically appraise evidence from a variety of
sources, integrate this material with the clinical expertise of
self and others, and include the individual and family's values
and goals when making clinical decisions.
As in previous editions, we have chosen to use “person
first” language in order to reflect the humanity and value of the
individuals we care for. While phrased such as “person with
stroke” or “person with amputation” may be cumbersome to
say or read than “patient” or “amputee” we feel strongly that
the use of person first language is well worth the extra time
or effort required. We hope that this example assists students
and clinicians using the text to embrace person centered care.
The text begins with a set of chapters that provide
foundation and context for the care of persons who might
benefit, in terms of function and of quality of life, from
prescription of an orthosis or prosthesis. While chapters on
exercise prescription for older adults, motor learning and
motor control, and evidence-based practice may not initially
seem to “fit” with the remaining chapters, they are written
with the intent to apply these concepts to the rehabilitation
of individuals using an orthosis or prosthesis, and we trust
that those who read them will recognize their relevance. The
chapters on assessment of the ability to walk, the methods
of fabrication and fitting, and on footwear choices have
obvious relevance.
The second part of the text takes us into the world of
orthotic design and application, starting with orthoses for
foot and lower limb, spine, and hand. We challenge our
Preface

x
Preface
readers to think not only about selecting the most appropriate
orthosis for persons with musculoskeletal or neuromuscular
system problems, but to also design a rehabilitation
intervention based on principles of motor learning that
will facilitate the person's use of the orthoses and ability to
participate in activities most meaningful to the individual.
We then consider wheelchairs and seating as an orthosis-
of-sorts, designed to enhance mobility for persons when
functional walking is not a viable option.
The third part of the text focuses on the care of persons
with amputation, beginning with consideration of why
amputations are performed, care of those at risk of amputation
(with prevention as a focus), how amputations are done, and
post-operative/pre-prosthetic care. The following chapters
provide overview of prosthetic options and alignment issues
for those with partial foot, transtibial, transhumeral, and
bilateral amputations. We then consider initial prosthetic
rehabilitation, and have added chapters on advance skills for
community function and of athletics following amputation.
The chapter on children with limb deficiency prompts us
to incorporate our understanding of motor, cognitive, and
emotional development, as well as family dynamics, into
prosthetic rehabilitation. We conclude with chapters on
prosthetic options and rehabilitation for persons with upper
extremity amputation; meant to provide exposure and “a place
to start” rather than mastery of this less common, but perhaps
more specialized aspect of prosthetic and rehabilitative care.
With this third edition of Orthotics and Prosthetics
in Rehabilitation, we hope that our work will enhance
collaboration, mutual respect, and communication, as
well as broaden the knowledge base of health professionals
involved in orthotic or prosthetic rehabilitation. It is our
belief that collaborative and interdisciplinary care not only
enriches clinical practice and teaching, but also insures
the best possible outcomes for the individuals we provide
rehabilitative care for.
Michelle M. Lusardi, PT, DPT, PhD
Milagros “Millee” Jorge, PT, MA, EdD
Caroline Nielsen, BA, MA, Ph.D

1
1
Building Baseline Knowledge
I
Orthotics and Prosthetics in Rehabilitation:
Multidisciplinary Approach
Caroline C. Nielsen and Milagros Jorge
Allied health professionals work in health care settings to
meet the physical rehabilitation needs of diverse patient
populations. Today's health care environment strives to
be patient-centered and advocates the use of best ­practice
­models that maximize patient outcomes while contain­
ing costs. The use of evidence-based treatment approaches,
clinical practice guidelines, and standardized outcome mea­
sures provides a foundation for evaluating and determining
efficacy in health care across disciplines. The World Health
Organization International Classification of Functioning,
Disability, and Health (ICF)1 provides a disablement frame­
work that enables health professionals to maximize patient/
client participation and function while minimizing disability.
In this complex environment, current and evolving patterns
of health care delivery focus on a team approach to the total
care of the patient.
For a health care team to function effectively, each ­member
must develop a positive attitude toward ­interdisciplinary
­collaboration.
The
collaborating
health
­professional
must understand the functional roles of each health care
­discipline within the team and must respect and value each
­discipline's input in the decision-making process of the
health team.2,3 Rehabilitation, particularly when related to
orthotics and prosthetics, lends itself well to interdisciplin­
ary teams because the total care of patients with complex
disorders requires a wide range of knowledge and skills.4
The ­physician, ­prosthetist, orthotist, physical therapist,
­occupational ­therapist, nurse, and social worker are impor­
tant ­participants in the ­rehabilitation team. Understanding
the roles and ­professional ­responsibilities of each of these
disciplines ­maximizes the ­ability of the rehabilitation team
members to function ­effectively to ­provide comprehensive
care for the patient.
According to disability data from the American Community
Survey 2003, 11.5% of civilian household populations aged
16 to 64 years reported having a disability.5 Approximately
1.7 million people in the United States live with limb loss.6
The U.S. military engagements in Iraq and Afghanistan have
resulted in limb loss for more than 1000 soldiers.7 The obe­
sity epidemic in the United States has given rise to more
people with ­diabetes who are at risk for ­dysvascular disease,
such as peripheral arterial ­disease (PAD), which often results
in ­musculoskeletal and ­neuromuscular ­impairments to the
LEARNING OBJECTIVES
On completion of this chapter, the reader will be able to:
1. Describe the role of the orthotist, prosthetist, physical
therapist, and other professionals in the rehabilitation of
persons with movement dysfunction.
2. Describe the history and development of physical
­rehabilitation professions associated with the practice of
orthotics and prosthetics in health care.
3. Identify the use of disablement frameworks in physical
rehabilitation.
4. Discuss the role of the health professional in a multi­
disciplinary or interdisciplinary rehabilitation team.
5. Determine key attributes and attitudes that health
­professionals should possess to be successful members of
interdisciplinary rehabilitation teams.

2
Section I  Building Baseline Knowledge
lower extremities. Ischemic disease can cause peripheral
­neuropathy, loss of ­sensation, poor skin care and wound
formation, trophic ulceration, osteomyelitis, and gangrene,
which can result in the need for amputation. Eight million
Americans have PAD.8
Persons coping with illness, injury, disease, impairments,
and disability often require special orthotic and prosthetic
devices to help with mobility, stability, pain relief, and skin and
joint protection. Appropriate prescription, fabrication, instruc­
tion, and application of the orthotic and prosthetic devices
help persons to engage in activities of daily ­living as indepen­
dently as possible. Prosthetists and ­orthotists are allied health
professionals who custom-fabricate and fit ­prostheses and
orthoses. Along with other health care ­professionals, includ­
ing nurses, physical therapists, and occupational therapists,
posthestists and orthotists are integral members of the reha­
bilitation teams responsible for returning patients to produc­
tive and meaningful lives. Definitions of disability continue
to evolve. Current ­definitions consider social, behavioral, and
environmental factors that affect the person's ability to func­
tion in society. These definitions have considerably broadened
the original pathology model in which disability was a func­
tion of a particular disease or group of diseases.9 The current,
more inclusive model requires expertise from many sectors
in rehabilitative care. This ­chapter discusses the developmen­
tal history of the art and science of orthotics, prosthetics, and
physical therapy as professions dedicated to rehabilitating
­persons with injury and disability.
PROSTHETISTS AND ORTHOTISTS
Prosthetists provide care to patients with partial or total
absence of limbs by designing, fabricating, and fitting pros­
theses or artificial limbs. The prosthetist creates the design to
fit the individual's particular functional and cosmetic needs;
selects the appropriate materials and components; makes all
necessary casts, measurements, and modifications (including
static and dynamic alignment); evaluates the fit and function
of the prosthesis on the patient; and teaches the patient how
to care for the prosthesis (Figure 1-1).
Orthotists provide care to patients with neuromuscular and
musculoskeletal impairments that contribute to ­functional
limitation and disability by designing, ­fabricating, and fitting
orthoses, or custom-made braces. The ­orthotist is responsi­
ble for evaluating the patient's functional and ­cosmetic needs,
designing the orthosis, and selecting appropriate ­components;
fabricating, fitting, and aligning the orthosis; and ­educating
the patient on appropriate use (Figure 1-2).
According to the U.S. Department of Labor, Bureau of
Labor Statistics, in 2009, there were 5470 certified prosthe­
tists and orthotists practicing in the United States.10 An indi­
vidual who enters the fields of prosthetics and orthotics today
must complete advanced education (beyond an undergradu­
ate degree) and residency programs before becoming ­eligible
for certification. Registered assistants and technicians in
­orthotics or prosthetics assist the certified practitioner with
patient care and fabrication of orthotic and prosthetic devices.
FIGURE  1-2  Once an orthosis has been fabricated, the orthotist
evaluates its fit on the patient to determine whether it meets pre­
scriptive goals and can be worn comfortably during functional activ­
ities or whether additional modifications are necessary. Here the
orthotist is fitting a spinal orthosis and teaching his young patient
about proper donning and wearing schedules.
FIGURE 1-1  The prosthetist evaluates, designs, fabricates, and fits
a prosthesis specific to a patient's functional needs. Here the pros­
thetist double-checks electrode placement sites for a myoelectrical
upper extremity prosthesis in a child with amputation of the left
forearm.

Chapter 1  Orthotics and Prosthetics in Rehabilitation: Multidisciplinary Approach
3
HISTORY
The emergence of orthotics and prosthetics as health profes­
sions has followed a course similar to the profession of phys­
ical therapy. Development of all three professions is closely
related to three significant events in world history: World
War I, World War II, and the onset and spread of polio in the
1950s. Unfortunately, it has taken war and disease to provide
the major impetus for research and development in these key
areas of rehabilitation.
Although the profession of physical therapy has its roots
in the early history of medicine, World War I was a major
impetus to its development. During the war, female “phys­
ical educators” volunteered in physicians’ offices and Army
hospitals to instruct patients in corrective exercises. After
the war ended, a group of these “reconstruction aides”
joined together to form the American Women's Physical
Therapy Association. In 1922, the association changed its
name to the American Physical Therapy Association, opened
­membership to men, and aligned itself closely with the ­medical
profession.11
Until World War II, the practice of prosthetics depended
on the skills of individual craftsmen. The roots of prosthet­
ics can be traced to early blacksmiths, armor makers, other
skilled artisans, and even the individuals with amputations,
who fashioned makeshift replacement limbs from materials
at hand. During the Civil War, more than 30,000 ­amputations
were performed on Union soldiers injured in battle; at least
as many occurred among injured Confederate troops. At that
time, most prostheses consisted of carved or milled wooden
sockets and feet. Many were procured by mail order from
companies in New York or other manufacturing centers at a
cost of $75 to $100 each.12 Before World War II, prosthetic
practice required much hands-on work and craftsman's skill.
D. A. McKeever, a prosthetist who practiced in the 1930s,
described the process: “You went to [the person with an
amputation's] house, took measurements and then carved a
block of wood, covered it with rawhide and glue, and sanded
it.” During his training, McKeever spent three years in a shop
carving wood: “You pulled out the inside, shaped the outside,
and sanded it with a sandbelt.”13
The development of the profession of orthotics mirrors the
field of prosthetics. Early “bracemakers” were also artisans
such as blacksmiths, armor makers, and patients who used
many of the same materials as the prosthetist: metal, leather,
and wood. By the eighteenth and nineteenth ­centuries,
splints and braces were also mass produced and sold through
­catalogs. These bracemakers were also frequently known
as “bonesetters” until surgery replaced manipulation and
­bracing in the practice of orthopedics. “Bracemaker” then
became a profession with a particular role distinct from that
of the physician.14
World War II and the period following were times of
­significant growth for the professions of physical ­therapy,
prosthetics, and orthotics. During the war, many more
physical therapists were needed to treat the wounded and
­rehabilitate those who were left with functional impairments
and disabilities. The Army became the major resource for
physical therapy training programs, and the number of physi­
cal therapists serving in the armed services increased more
than sixfold.15 The number of soldiers who required braces or
artificial limbs during and after the war increased the demand
for prosthetists and orthotists as well.
After World War II, a coordinated program for persons
with amputations was developed. In 1945, a conference
of surgeons, prosthetists, and scientists organized by the
National Academy of Sciences revealed that little scientific
effort had been devoted to the development of artificial limbs.
A “crash” research program was initiated, funded by the
Office of Scientific Research and Development and continued
by the Veterans Administration. A direct result of this effort
was the development of the patellar tendon-bearing prosthe­
sis for individuals with transtibial (below-knee) amputation
and the quadrilateral socket design for those with transfem­
oral (above-knee) amputation. This program also included
­educating prosthetists, physicians, and physical therapists in
the skills of fitting and training of patients with these new
prosthetic designs.16
The needs of soldiers injured in the military conflicts in
Korea and Vietnam ensured continuing research, ­further
refinements, and development of new materials. The develop­
ment of myoelectrically controlled upper extremity prosthe­
ses and the advent of modular endoskeletal lower extremity
prostheses occurred in the post–Vietnam ­conflict era. In 2008,
the U.S. Department of Defense reported military operations
in Iraq and Afghanistan (Operations Enduring Freedom
and Iraq Freedom) have resulted in loss of limb for 1214
­service men and women.17 Veterans Health Administration
Research Development is committed to exploring the use
of new ­technology such as robotics, tissue engineering, and
­nanotechnology to design and build lighter, more functional
prostheses that look, feel, and respond more like real arms
and legs.18
The current term, orthotics, emerged in the late 1940s and
was officially adopted by American orthotists and prosthetists
when the American Orthotic and Prosthetic Association was
formed to replace its professional predecessor, the Artificial
Limb Manufacturers’ Association. Orthosis is a more inclu­
sive term than brace and reflects the development of devices
and materials for dynamic control in addition to stabilization
of the body. In 1948, the American Board for Certification
in Orthotics and Prosthetics was formed to establish and
­promote high professional standards.
Although the polio epidemic of the 1950s played a role in
the further development of the physical therapy profession,
this epidemic had the greatest effect on the development
of orthotics. By 1970, many new techniques and materials,
some adapted from industrial techniques, were being used to
assist patients in coping with the effects of polio and other
­neuromuscular disorders. The scope of practice in the field
of orthotics is extensive, including working with children
with muscular dystrophy, cerebral palsy, and spina bifida;
patients of all ages recovering from severe burns or fractures;
­adolescents with scoliosis; athletes recovering from surgery

4
Section I  Building Baseline Knowledge
or injury; and older adults with diabetes, cerebrovascular
accident, severe arthritis, and other disabling conditions.
Like physical therapists, orthotists and prosthetists
­practice in a variety of settings. The most common setting
is the ­private office, where the professional offers services to
a patient on referral from the patient's physician. Many large
institutions, such as hospitals, rehabilitation centers, and
research institutes, have departments of orthotics and pros­
thetics with on-site staff to provide services to patients. The
prosthetist or orthotist may also be a supplier or fabrication
manager in a central production laboratory. In addition, some
orthotists and prosthetists serve as full-time faculty in one of
the 10 programs that are available for orthotic and prosthetic
entry-level training or in one of the programs available at the
master of science level.19 Others serve as clinical educators
in a variety of facilities for the year-long residency program
required before the certification examination.
PROSTHETIC AND ORTHOTIC PROFESSIONAL
ROLES AND RESPONSIBILITIES
With rapid advances in technology and health care, the roles
of the prosthetist and orthotist have expanded from a tech­
nological focus to a more inclusive focus on being a member
of the rehabilitation team. Patient examination, evaluation,
education, and treatment are now significant responsibili­
ties of practitioners. Most technical tasks are completed by
technicians who work in the office or in the laboratory, or
at an increasing number of central fabrication facilities. The
advent and availability of modifiable prefabrication systems
have reduced the amount of time that the practitioner spends
crafting new prostheses and orthoses.
Current educational requirements reflect these changes
in orthotic and prosthetic practice. Entry into professional
training programs requires completion of a bachelor's degree
from an accredited college or university, with a strong empha­
sis on prerequisite courses in the sciences. Professional edu­
cation in orthotics or prosthetics requires an additional
academic year for each discipline. Along with the necessary
technical courses, students study research methodology,
kinesiology and biomechanics, musculoskeletal and neu­
romuscular pathology, communication and education, and
current health care issues. Orthotics and prosthetics pro­
grams are most often based within academic health centers
or in colleges or universities with hospital affiliations. After
completion of the ­academic program, a year-long residency
begins, during which new clinicians gain expertise in the
acute, rehabilitative, and long-term phases of pediatrics and
adult care. On completion of the educational and experien­
tial requirements, the student is eligible to sit for the certi­
fication examinations. In order to address the rehabilitation
needs of individuals who will benefit from the art and science
of the fields of prosthetics and orthotics, physical therapists,
orthotists, prosthetists, and other members of the health care
team must have discreet knowledge and skills in the manage­
ment of persons with a variety of health conditions across the
lifespan. Working as a rehabilitation team, physicians, nurses,
­prosthetists, ­orthotists, physical therapists, occupational
­therapists, social workers, patients, and family members seek
to maximize function and alleviate disease, injury, impair­
ments, and disability.
DISABLEMENT FRAMEWORKS
Historically, disability was described using a theoretical
medical model of disease and pathology. Over time, ­various
conceptual frameworks have been developed to ­organize
information about the process and effects of ­disability.20
Disablement frameworks in the past have been used to
understand the relationship of disease and pathology to
human function and disability.20–23 The need to understand
the impact that acute injury or illness and chronic health
conditions have on the functioning of specific body systems,
human ­performance in general, and on the typical activities
of daily living from both the individual and a societal perspec­
tive has been central to the development of the disablement
models. The biomedical model of pathology and dysfunc­
tion provided the conceptual framework for understanding
human function, disability, and handicap as a consequence of
pathological and disease processes.
The Nagi model was among the first to challenge the
­appropriateness of the traditional biomedical model of
­disability.21 Nagi developed a model that looked at the indi­
vidual in relationship to the pathology, functional limita­
tions, and the role that the environment and society or the
social environment played. The four major elements of
Nagi's ­theoretical formulation included active pathology
(interference with normal processes at the level of the cell),
­impairment (anatomical, physiological, mental, or emotional
abnormalities or loss at the level of body systems), functional
limitation (limitation in performance at the level of the indi­
vidual), and disability. Nagi defined disability as “an expres­
sion of physical or mental limitation in a social context.”21 The
Nagi model was the first theoretical construct on disability
that considered the interaction between the individual and
the environment from a sociological perspective rather than a
purely biomedical perspective. Despite the innovation of the
Nagi model in the 1960s, the biomedical model of disability
persisted.
In 1980, the World Health Organization (WHO) ­developed
the International Classification of Impairments, Disabilities,
and Handicaps (ICIDH) to provide a standardized means
of classifying the consequences of disease and injury for the
­collection of data and the development of social policy.24 This
­document provided a framework for organizing information
about the consequences of disease. However, it focused solely
on the effects of pathological processes on the individual's
activity level. Disability was viewed as a result of an impair­
ment and considered a lack of ability to perform an activity
in the normal manner. In 1993, the WHO began a revision
of ICIDH disablement framework that gave rise to the con­
cept that a person's handicap was less related to the health
condition that created a disadvantage for completing the nec­
essary life roles but rather to the level of participation that

Chapter 1  Orthotics and Prosthetics in Rehabilitation: Multidisciplinary Approach
5
the ­person with the health condition was able to engage in
within the environment. The concept of being handicapped
was changed to be seen as a consequence of the level of
participation for the person and the interaction within an
environment.
The Institute of Medicine enlarged Nagi's original con­
cept in 1991 to include the individual's social and physi­
cal environment (Figure 1-3). This revised model describes
the environment as “including the natural environment, the
built environment, the culture, the economic system, the
political system, and psychological factors.” In this model,
­disability is not viewed as a pathosis residing in a person but
instead is a function of the interaction of the person with the
environment.25
In 2001, ICIDH was revised to ICIDH-2 and renamed
“International Classification of Functioning, Disability
and Health” and is commonly referred to as ICF.26 The ICF
­disablement framework includes individual function at the
level of body/body part, whole person, and whole person
within a social context. The model helps in the description
of changes in body function and structure, what people with
particular health conditions can do in standard environ­
ments (their level of capacity), as well as what they actually
do in their usual environments (their level of ­performance).
One of the major innovations of the ICF model is the
­presence of an ­environmental factor classification that con­
siders the role of environmental barriers and facilitators in
the ­performance of tasks of daily living. Disability becomes
an umbrella term for impairments, activity limitations,
and participation restrictions. The ICF model emphasizes
health and functioning rather than disability. The ICF model
­provides a radical departure from emphasizing a person's
­disability to focusing on the level of health and facilitating
an individual's ­participation to whatever extent is possible
within that level of health. In the ICF, disability and func­
tioning are viewed as outcomes of interactions between
health conditions ­(diseases, disorders, and injuries) and con­
textual factors (Figure 1-4).
The evolution of disablement frameworks from the
­biomedical models to the newer, contemporary models that
include the biopsychosocial domains provides ­theoretical
constructs that guide the rehabilitation professional in clin­
ical practice. Input from all members of the rehabilita­
tion team is essential in addressing the pathosis or disease
­process, impairments, functional limitations, and ­disabilities.
Interrelationships among all four of these elements are the
focus of the rehabilitation team. The physical therapist,
orthotist, prosthetist, and other team members work together
Biological factors
Congenital conditions and
genetic predispositions
Pathology/
pathophysiology
of the cell or tissue
Comorbidities,
health habits, and
lifestyle behaviors
Physical and social/psychological environments
Medical care
Medications/therapies
Rehabilitation
Psychological attributes,
motivation, expectations,
coping, sense of safety,
and social support
Impairment
of physiological systems
Functional limitation
Activity limitation
of the individual
Disability
Participation restriction
in social roles
Demographic factors
Age, gender,
education, and income
Health prevention strategies
Promotion of health, wellness, and fitness
Health-related quality of life
Overall quality of life
FIGURE 1-3  The revised Institute of Medicine/Nagi model of the disablement process considers the impact of pathological conditions and
impairment as well as intraindividual and extraindividual factors that may influence functional limitation and disability affecting health-
related and overall quality of life. (Modified from Guccione AA: Arthritis and the process of disablement. Phys Ther 1994;74[5]:410.)

6
Section I  Building Baseline Knowledge
to create the most effective outcome for the patient by identi­
fying and addressing pathological processes, functional limi­
tations, impairments, and disability. The classification system
developed by the WHO in the ICF document allows for data
collection that can be useful in research leading to improved
patient interventions, assessment of patient outcomes, and
development of health and social policies. Implementation of
this model of disability has been demonstrated to “improve
considerably the quality of interdisciplinary work processes
and contribute to a more systematic approach to rehabilita­
tion tasks by the team members.”26
CHARACTERISTICS OF REHABILITATION
HEALTH CARE TEAMS
The complexity of the health care arena and the level of care
required by individuals in rehabilitation care settings require
the collaboration of many health care practitioners with
varied professional skills who can form multidisciplinary,
­interdisciplinary, and transdisciplinary teams as needed.
The multidisciplinary rehabilitation team is comprised of
the ­different health professionals such as the physician,
nurse, physical therapist, occupational therapist, prosthetist,
­orthotist, and social worker. Each professional operates with
an area of ­specialization and expertise. The ­multidisciplinary
team is hierarchically structured and typically led by the ­highest
ranking member of the team.27 Although the ­multidisciplinary
team has varied ­representation of health providers, they may
or may not interact in a ­collaborative manner. The members
of the multidisciplinary team work parallel to one another,
and the medical record is the ­collecting source for the infor­
mation gleaned and shared. Interdisciplinary teams also
include the representatives of a variety of health ­disciplines,
but there is interdependence among the ­professionals.27 In
the interdisciplinary team ­process, there is structure and
organization that promotes program planning to support
­patient-centered care through effective communication and
effective clinical management.28 The interdisciplinary team
members work to establish goals for the team that drive the
rehabilitation process for the patient. Interdisciplinary teams
traditionally ­follow a patient-centered approach to goal
­setting. Establishing the patient as the focus of the work for
the team, the interdisciplinary team members collaborate to
execute the goals and meet the desired outcomes. Most team
processes in rehabilitation centers strive for an interdisciplinary
team approach that promotes patient-centered care. Each
discipline works within its scope of practice to optimize care
through coordinated efforts.
Transdisciplinary teams are comprised of the same
­professional members identified in the multidisciplinary
and transdisciplinary teams; however, the team members
in the transdisciplinary model function differently in that
they share clinical responsibilities and overlap in duties
and responsibilities. In the transdisciplinary model of team
building, the professional roles and responsibilities are so
familiar to the team members that there is an interchange
of tasks and functions.27 Transdisciplinary teams engage in
release of professional roles typical to the discipline in an
effort to have the patient receive the interventions needed
within a ­context that is supportive of the learning and the
practice. The transdisciplinary model is operational in the
management of infants and children who receive early inter­
vention rehabilitation services and have an Individualized
Family Service Plan (IFSP).
Two major issues emerging in health care that affect health
care professionals include (1) the need for health care profes­
sionals with advanced education and training in ­specialty and
subspecialty areas, and (2) the need for collaboration among
health practitioners to ensure efficiency of patient manage­
ment that results in best practice and improves patient out­
comes. The information explosion in health care, particularly
in rehabilitation, has led to increasing specialization and sub­
specialization in many fields. The interdisciplinary health
care team concept has evolved, in part, because no single indi­
vidual or discipline can have all the necessary expertise and
specialty knowledge required for high-quality care, especially
the care of patients with complex disorders. Interdisciplinary
rehabilitation health care teams provide patient care man­
agement approaches that capitalize on clinical expertise by
engaging members from diverse rehabilitation professions
working together, collaborating, and communicating closely
to optimize patient care.28
Collaboration is defined as a joint communication and
decision-making process with the goal of meeting the health
care needs of a particular patient or patient population.
Disorder or disease
Activity
Execution of
tasks by the
individual
Participation
Involvement
in life
situations
Body
functions
Body
structures
Health condition
Contextual factors
Environmental factors
Social attitudes/expecta-
tions, health care and
legal systems, social
structures, family and
support systems, climate
and terrain, and architec-
tural characteristics
Personal factors
Gender, age, economic
status, coping styles,
expectations, social
background, education/
intellect, past and current
experience, and overall
behavior patterns
FIGURE 1-4  WHO uses a biopsychosocial model as the basis for its
International Classification of Functioning, Disability and Health.
(Modified from World Health Organization. Towards a Common
Language for Functioning, Disability and Health. Geneva: World
Health Organization, 2002. pp. 9-10.)

Chapter 1  Orthotics and Prosthetics in Rehabilitation: Multidisciplinary Approach
7
Each participant on the rehabilitation team brings a particu­
lar expertise, and leadership is determined by the particular
rehabilitation situation being addressed. The rehabilitation
team has the opportunity to meet and engage in “asking the
answerable questions” that are critical in clinical practice today
when engaging in an evidence-based model of practice.29
According to Sackett and colleagues,29 evidence-based
­practice is the integration of the best research evidence, clini­
cal expertise, and patient values. Evidence-based practice and
clinical decision-making enhance the role of the rehabilita­
tion team professionals as they share their clinical insights
supported by historical and current evidence. Rehabilitation
teams that are diverse in professional representation can
bring a wide perspective of expertise on particular rehabili­
tation issues. With this perspective, clinical decision making
becomes a more inclusive process.
The role of the health care professional on a rehabilitation
team begins during professional education. Rehabilitation
sciences health professionals must work at understanding,
evaluating, and analyzing the many facets of health care that
require specialized professionals who will work to meet the
goals and objectives of the specialty and of health care ­delivery
on the whole. The formation of a rehabilitation team provides
a cohort of professionals who individually and collectively
strive for effective and efficient management of patients.
The team process allows for a deeper understanding of and
appreciation for the contributions of the other ­rehabilitation
­disciplines in the assessment and treatment of the patient and
management of patient problems.
In addition to discipline-specific skills and knowledge,
health professionals must be aware of the interrelation­
ships among health care workers. One of the major ­barriers
to ­effective team functioning is a lack of understanding or
­misconception of the roles of different disciplines in the
care of the whole patient.30 A clear understanding of the
­totality of the health care delivery system and the role of each
­professional within the system increase the potential effec­
tiveness of the health care team. A group of informed, dedi­
cated health professionals working together to set appropriate
goals and initiate patient care to meet these goals uses a model
that exceeds the sum of its individual components.
Almost all rehabilitation health care today is provided
in a team setting using a patient-centered approach. This
­integrated approach facilitates appreciation of the patient as
a person with individual strengths and needs rather than as
a dehumanized diagnosis or problem. The diverse perspec­
tives and knowledge that are brought to the rehabilitation
process by the members of the interdisciplinary team provide
insight into all aspects of the patient's concerns. Conceptually,
all members of the health care team contribute equally to
patient care. The contribution of each is important and valu­
able; otherwise, quality of patient care and efficacy of inter­
vention would be diminished. Although one member of the
team may take an organization or management role, decision
making occurs by consensus building and critical discus­
sion. Professionals with different skills function together with
mutual support, sharing the responsibility of patient care.
Effective team-based health care assumes that groups of
health care providers representing multiple disciplines can
work together to develop and implement a comprehensive,
integrated treatment plan for each patient. This requires
­professionals, who have traditionally worked independently
and autonomously, to function effectively in interdependent
relationships with members of other disciplines.31 However,
this may not be an easy task to accomplish because of the
­considerable potential for dysfunction.
The Oxford English Dictionary defines team as “two or
more persons working together.”32 Pearson and Jones define
a team as “a small group of people who relate to each other to
contribute to a common goal.”33 Much of our understanding of
team function is drawn from organization and ­management
research literature, the theories of which ­provide insight and
information on how interdisciplinary teams operate and the
factors that facilitate or inhibit their effectiveness. A ­number
of factors are important influences on health ­professionals’
perception of team membership that can be positive or
­negative to the team process.
Values and Behaviors
Some of the factors that tend to limit the effectiveness of
a work group are large group size, poor decision-making
­practices, lack of fit between group members’ skills and
task demands, and poor leadership.34–36 Other factors that
­influence team dynamics are classified as formal (tangible or
visible) and informal (submerged). Formal factors include
the policies and objectives of the group or its parent organi­
zation, the systems of communication available to the group,
and the job descriptions of its members. Informal factors,
which are often less obvious but equally influential on group
process, include working relationships among team mem­
bers; power networks within and external to the group; and
the values, beliefs, and goals of individuals within the group
(Box 1-1).33 Team-building initiatives are often focused on
Modified from Pearson P, Jones K. The primary health care
non-team? Dynamics of multidisciplinary provider groups.
BMJ 1994;309(6966):1387-1388.
FORMAL (VISIBLE) INFLUENCES
Policies of the group or institution
Objectives of the group
Formal systems of communication
Job descriptions of group members
INFORMAL (SUBMERGED) INFLUENCES
Informal relationships among team members
Communication styles of team members
Power networks within the group
Individual values and beliefs
Goals/norms of individuals in the group
BOX 1-1  Formal and Informal Factors
That Influence Dynamics of the
Multidisciplinary Work Group

8
Section I  Building Baseline Knowledge
the formal, or visible, areas, but informal communication,
values, and norms play key roles in the functioning of the
health care team.
A variety of characteristics and considerations also enhance
the effectiveness of the interdisciplinary health care team.
In addition to having strong professional ­backgrounds and
appropriate skills, team members must appreciate the diver­
sity within the group, taking into account age and ­status differ­
ences and the dynamics of individual ­professional subgroups.35
The size of the team is also important: the most capable and
effective teams tend to have no more than 12 members. Team
members who know each other and are aware of and value
each other's skills and interests are often better able to set and
achieve goals. Clearly defined goals and ­objectives about the
group's purpose and ­primary task, ­combined with a shared
understanding of each ­member's roles and skills, increase the
likelihood of effective communication.
Values and behaviors that facilitate the collaborative team
care model include the following:
• Trust among members that develops over time as ­members
become more familiar with each other
• Knowledge or expertise necessary for the development
of trust
• Shared responsibility for joint decision-making regarding
patient outcomes
• Mutual respect for all members of the team
• Two-way communication that facilitates sharing of patient
information and knowledge
• Cooperation and coordination to promote the use of skills
of all team members
• Optimism that the team is indeed the most effective means
of delivering quality care
In the early stages of development, it is essential that the
team spend time developing goals, tasks, roles, leadership,
decision-making processes, and communication methods.
In other words, the team needs to know where it is going,
what it wants to do, who is going to do it, and how it will
get done.37 One of the most important characteristics of
an effective health care team is the ability to accommodate
­personal and professional differences among members and to
use these differences as a source of strength. The well-func­
tioning team often becomes a means of support, growth, and
increased effectiveness and professional satisfaction for the
physical therapist and other health professionals who wish to
­maximize their strengths as individuals while participating in
professional responsibilities.38
Rehabilitation Teams
The interdisciplinary health care team has become essen­
tial in the rehabilitation of patients whose body function
and level of participation in the tasks of daily living could
be enhanced by assistive technology such as an orthosis or
prosthesis. The complexity of the rehabilitation process and
the multidimensional needs of patients frequently require
the expertise of many different professional disciplines. The
rehabilitation team is often shaped by the typical needs and
­characteristics of the patient population that it is designed
to serve. The ­individuals most often represented on the
­rehabilitation team include one or more physicians with
specialties in ­rehabilitation medicine, orthopedics, vascu­
lar surgery or neurology, nurses, prosthetists and/or ortho­
tists, physical therapists, occupational therapists, dietitians,
social workers, vocational rehabilitation counselors, as well
as patients and caregivers (Figure 1-5). Each member of the
interdisciplinary team has an important role to play in the
rehabilitation of the patient. Patient education is often one
of the primary concerns of the team. Imparting information
regarding the health condition, etiology, treatment, progres­
sion, management, and ­prognosis helps patients become
active partners in the rehabilitation ­process rather than pas­
sive recipients of care. Patient education addresses preven­
tion and treatment ­strategies; patients and their families are
able to identify their needs and concerns and communicate
them to the team members. Each member of the team has
the responsibility for contributing to patient education, so
that patients have the information needed for an effective
partnership and positive outcome of rehabilitation efforts.
Research studies across a wide variety of medical ­conditions
and health disciplines contain evidence that patients who
feel prepared and informed are most likely to invest in and
­comply with recommended interventions and often have
the most positive health outcome. Ideally, patient education
about amputation and prosthetics begins in advance of, or at
least immediately after, the amputation surgery.39 A national
survey of people with amputations (n = 109) revealed that
information is often scarce at this crucial time.40 Individuals
with recent amputations are often caught in an informa­
tion gap in the days between surgery and the initial process
Patient
Physical
therapist
Prosthetist
Social
worker
Dietitian
Occupational
therapist
Physician
Orthotist
Nurse
FIGURE 1-5  A key characteristic of the successful health care team
is a clear understanding of the role, responsibilities, and unique skills
and knowledge of each member of the rehabilitation team, ­combined
with open and effective communication.

Chapter 1  Orthotics and Prosthetics in Rehabilitation: Multidisciplinary Approach
9
of prosthetic prescription and fitting. Only approximately
50% of patients with a new amputation received informa­
tion about the timing and process of rehabilitation or about
prosthetic options before or immediately after amputation.40
Interestingly, the health professional most frequently cited as
a provider of information at the time of amputation was the
physical therapist (25%), followed by the physician (23%).
The health professionals cited as most helpful after ampu­
tation were the prosthetist (65%) and the physical therapist
(23%) (Table 1-1). Clearly, one of the most valued contribu­
tions of the physical therapist, in addition to the traditional
role in facilitating a patient's mobility and independence, is as
a provider of early information about the timing and process
of the prosthetic fitting and training.
The respondents in this study desired to be active par­
ticipants in treatment planning and rehabilitation decision-
making in partnership with the health care team. The keys
to the patient's successful participation in the rehabilitation
team are efforts to provide more information and oppor­
tunity for open communication; both are likely to enhance
patient satisfaction and compliance and the achievement of a
positive clinical outcome.
Coordinated patient-centered care by an interdisciplin­
ary rehabilitation team is just as essential for effective reha­
bilitation of children as it is for adults. For children with
myelomeningocele or cerebral palsy, the broad knowledge
base available through team interaction provides a stronger
foundation for tailoring interventions to the ever-changing
developmental needs of the child and family.41,42 The optimal
delivery of care for children is best provided in a comprehen­
sive health care setting in which the various specialists can
provide a truly collaborative approach. Orthopedic surgeons,
neurologists, orthotists, prosthetists, physical therapists,
occupational therapists, nurses, dietitians, social workers,
psychologists, and special education professionals may all be
involved in setting goals and formulating and carrying out
plans for intervention and outcomes assessment.
The concept of a multidisciplinary pediatric clinic team was
formulated as World War II came to an end.43 This structure
has evolved further over the years and is particularly ­effective
for the more complex orthotic and prosthetic ­challenges.
A “mini-team” consisting of the patient's physician, a physical
therapist, and a prosthetist or orthotist can usually be assem­
bled, even in a small town with few facilities. Regardless of its
size, an effective team views the child and family from a holis­
tic perspective, with the input from each specialty being of
equal value. Under these circumstances, the setting of treat­
ment priorities, such as whether prosthetic fitting or training
in single-handed tasks is most appropriate at a child's current
age or developmental level, is made on the basis of the par­
ticular needs of the individual.44 Children with orthotic and
prosthetic needs are followed in the community and within
the school setting. As appropriate, a child may receive reha­
bilitation or habilitation services under the Individuals with
Disabilities Education Act (IDEA).45 The rehabilitation/edu­
cational team is a diverse group of health care professionals,
educators, family, and caregivers, each with essential skills
necessary to address the needs of the child that encourage
maximum participation in tasks of daily living. Each member
of the team works in a collaborative manner with the family
and caregivers, and with the child's teachers and other health
professionals to ensure that the goals of the Individualized
Family Service Plan (IFSP) or the Individualized Education
Plan (IEP) are addressed and met. Clear and frequent com­
munication is essential for the team to function effectively
and to achieve the desired outcomes for the child.
TABLE 1-1  Health Professionals Cited as Sources of
Information to Persons with Amputations
(n = 109)



Health Discipline
Provided
Information
at Time of
Amputation

Most Helpful
After
Amputation
Physical therapist
24 (25%)
22 (23%)
Prosthetist
18 (19%)
63 (65%)
Surgeon/family physician
22 (23%)
28 (29%)
Others with amputation
21 (22%)
7 (7%)
Values are n (%).
Data from Nielsen CC. A survey of amputees: functional level and life
satisfaction, information needs, and the prosthetist's role, J Prosthet
Orthot 1991;3(3):125.
CASE EXAMPLE 1
Interdisciplinary Teams
P. G. is a 23-year-old man admitted to a level 3 trauma cen­
ter two weeks ago after sustaining severe crush injuries to
both lower extremities and a closed-head injury in an acci­
dent involving a motorcycle and a sport utility vehicle.
Initially, unconscious with a Glasgow Coma Scale score of
8, P. G. was placed on life support in the emergency depart­
ment. Radiographs revealed a severely comminuted frac­
ture of the distal right femur and displaced fractures of the
left tibia and fibula at midshaft. Examination revealed par­
tial thickness “road burn” abrasions on the left anterior tho­
rax and thigh; these were thoroughly cleaned and covered
with semipermeable dressings. A computed tomography
scan of his ­cranium and brain revealed a subdural hema­
toma over the left sylvian fissure and moderate contusion
of the ­anterior pole and undersides of the frontal lobes.
Arteriography indicated rupture of the right femoral artery
4 inches above the knee. Given the extent of the crush inju­
ries, the trauma team determined P. G. was not a candidate
for reconstructive surgery to salvage his right limb.
P. G. was taken to the operating room, where a
­standard length transfemoral amputation was per­
formed on the right lower extremity. Simultaneously,
orthopedic ­surgeons performed an open-reduction
Continued

10
Section I  Building Baseline Knowledge
internal fixation with an intramedullary rod in the tibia
and used surgical plates and screws to repair the fib­
ula. Neurosurgeons drained the subdural hematoma
through a burr hole in his skull. P. G. was started on
high-dose broad-spectrum ­antibiotics in the operating
room. He was transferred to the surgical intensive care
unit for postoperative care.
P. G. was weaned from the ventilator and is now
­functioning at a Rancho Los Amigos Scale level of 7. He is
able to follow one- and two-step commands but becomes
easily confused and angry in complex environments and
when fatigued. His postoperative pain is ­currently being
managed with Tylenol #3 as needed. His right lower
extremity has been managed with soft dressings and
­elastic bandages; his residual limb is moderately bulbous,
with resolving ecchymosis from the accident and ­surgery.
Moderate serosanguineous drainage continues from the
medial one third of the suture line. Although most of
the skin abrasions show signs of regranulation, one area
on his left thigh is red and hot, with yellowish drainage.
When transferred (maximum assist of two) into a bedside
recliner, P. G. tolerates 30 minutes in a 45- to 60-degree
reclined position. He becomes lightheaded and has signifi­
cant pain when sitting upright with his left lower ­extremity
dependent. He has been referred to physical therapy for
evaluation of rehabilitation potential and initiation of
mobility activities.
Before his accident, P. G. was a graduate student in
­physics at a nearby university. He lived in a third floor
walk-up apartment with his fiancé and his golden retriever.
Besides his motorcycle, his interests and hobbies included
long distance running and mountain climbing. His mother
and father have traveled to be with him during the acute
­hospital stay.
Questions to Consider
• Who are the clinical specialists and health profes­
sionals needed to address the medical needs of the
patient?
• What are the priorities, specific roles, and responsibili­
ties for each potential member of the team? What team
structure do you envision?
• How are the roles and responsibilities similar or
­different across the team?
• What external influences will affect team formation
and functioning in a busy level 3 trauma center?
• What factors might facilitate team development?
• What factors might challenge the effectiveness of
the team?
• As P. G. recovers from his injuries, how might the roles
and responsibilities of the various team members change
or evolve?
• When and how would you apply the ICF disablement
model for P. G.?
CASE EXAMPLE 2
Interdisciplinary Teams
E. L. is a 73-year-old woman with a 10-year history of
type 2 diabetes mellitus. She is insulin dependent. Two
weeks before her most recent hospitalization, she and her
­husband (who is in the early stages of Alzheimer disease)
moved from their home of 50 years to an assisted-living
complex in a neighboring town. Although the furniture is
set up and functional, they have not had the chance to fully
unpack and make the apartment their own.
Over the past three years, E. L. has been monitored by
her team of physicians for progressive polyneuropathy of
­diabetes and for moderate peripheral vascular ­disease. She
had a transmetatarsal amputation of her right ­forefoot
eight months ago because of nonhealing recurrent neuro­
pathic ulcer. Despite wearing custom-molded shoes and
accommodative orthoses, another ulcer of her first meta­
tarsal head developed on the left foot two months ago.
This new ulcer did not heal with conservative care and
progressed to osteomyelitis two weeks ago. When vascu­
lar ­studies ­suggested inadequate circulation to heal the
ulcer she received arterial revascularization intervention,
but the ischemia persisted and E. L. underwent an elective
transtibial amputation of her left lower extremity. Despite
a short bout of postoperative delirium thought to be
related to pain management with morphine, E. L. (5 days
postoperatively) was adamant about returning to her new
assisted-living apartment, using a wheelchair for mobility,
and receiving home care until her residual limb is healed
and ready for prosthetic fitting.
Currently she is able to ambulate two lengths of 15-foot-
long parallel bars before needing to rest and has begun
gait training with a “hop-to” gait pattern with a standard
walker. She is able to transfer from sitting on a firm ­seating
surface with armrests to standing with standby guarding
and verbal cueing, and needs minimal assistance from
low and soft seats without armrests. She believes that she
and her husband will be able to manage at home because
her bathroom has grab bars on the toilet, and a tub seat
and handheld shower head are available from the “loaner
closet” at her assisted-living facility.
At discharge, the suture line had one small area of
­continued moderate drainage, requiring frequent dressing
changes. She is unable to move her residual limb into a posi­
tion for effective visual self-inspection of the healing sur­
gical wound without significant discomfort. Her husband,
although attentive, becomes confused with the routine of
wound care. E. L.'s postoperative limb volume and edema
are being managed with a total contact cast, which she is able
to don and doff independently. She had one late evening fall,
when she awoke from a sound sleep having to go to the bath­
room and was surprised when her left limb “wasn't really
there” to stand on when she tried to get out of bed.

Chapter 1  Orthotics and Prosthetics in Rehabilitation: Multidisciplinary Approach
11
SUMMARY
Patient-centered care in in-patient rehabilitation and ambu­
latory community settings today relies on interdisciplin­
ary rehabilitation teams that function to address the patient
goals and maximize patient outcomes. The use of rehabili­
tation teams has evolved in part because no one person or
discipline has the expertise in all the areas of specialty knowl­
edge required for the established standards of care. This situ­
ation is particularly true for meeting the health care needs of
persons in orthotic and prosthetic rehabilitation. The success
of the rehabilitation team process requires health professionals
to work together in a collaborative and cooperative manner. The
rehabilitation team professional must demonstrate attitudes and
attributes that foster collaboration, including35:
1. Openness and receptivity to the ideas of others
2. An understanding of, value of, and respect for the roles
and expertise of other professionals on the team
Since her amputation, E. L.'s insulin dosages have
had to be adjusted frequently because of unpredictable
changes in her serum glucose levels. She has lost 20 pounds
(half of which can be attributed to her amputation) since
admission.
Questions to Consider
• Who are the health care professionals likely to be
involved in her care?
• Which team approach is most desirable for patient-
centered care: multidisciplinary, interdisciplinary, or
transdisciplinary? Why?
• What are the major challenges facing the team of care
providers involved in the postoperative, preprosthetic
care of E. L and her husband? How are these similar
to or different from challenges and issues the trauma
­center team considered before her amputation?
• What strategies are currently in place or must be
­developed to ensure that E. L.'s care at home is compre­
hensive and coordinated?
• How will the roles and responsibilities of the team
members evolve and change as she recovers from her
surgery and is ready to begin prosthetic use?
• When and how would you apply the ICF disablement
model for E. L.?
CASE EXAMPLE 3
Interdisciplinary Teams
M. S. is a 12-year-old girl with myelomeningocele (spina
bifida) who uses a wheelchair for mobility. In the past year
she has developed significant thoracolumbar scoliosis
believed to be associated with a growth spurt. Concerned
about the rate of increase in her S-shaped thoracolum­
bar curve, her parents sought the advice of an orthopedic
­surgeon who has been involved as a consultant in her care
since birth. The surgeon recommends surgical ­stabilization
of M. S.'s spine with Harrington rods and bony fusion to
(1) prevent further progression of the curve and rib hump
so that secondary impairment of the ­respiratory system
will be minimized as she grows and (2) ­provide more
­efficient upright sitting posture for wheelchair propulsion
in the years ahead.
M. S. currently attends classes in her neighborhood
middle school where she receives related health services
including physical therapy. Until two years ago, she ambu­
lated for exercise by using a reciprocal gait orthosis during
gym periods at school, but with recent spurts in growth
the use of a manual wheelchair is more efficient for mobil­
ity (to keep up with her classmates). She is also followed
up on a regular basis by a neurologist who monitors the
operation of her ventriculoperitoneal shunt (commonly
used in the management of hydrocephalus associated with
myelomeningocele).
In addition to their concerns about the risk of the sur­
gical procedure, M. S.'s parents are quite concerned about
how the anticipated four-month postoperative immobi­
lization in a thoracolumbosacral orthosis will affect her
capacity for self-care and independent wheelchair mobil­
ity. They are also concerned about how the surgery and
postoperative period will potentially interrupt the effec­
tive bowel and bladder management routine for which
M. S. has just begun to assume responsibility. As witnesses
to their daughter's deconditioning and loss of stamina over
the past six months, they are concerned that she might
not be “physically ready” for the surgery and postopera­
tive rehabilitation. They are also asking questions about
whether this spinal surgery will ultimately improve the
prognosis of a successful return to ambulation with her
reciprocal gait orthosis.
Questions to Consider
• Who are the members of the rehabilitation team?
• What is the structure of the team that will best address
the needs of the patient?
• What are the priorities, roles, and responsibilities of the
health professionals involved in the care of this child
and her family?
• How is the composition of M. S.'s rehabilitation team
similar to or different from that of P. G.'s and E. L.'s
teams?
• How will the health and education professionals sup­
port M. S. and her family through the postoperative
recovery process?
• When and how would you apply the ICF disablement
model to M. S.?

12
Section I  Building Baseline Knowledge
3. Value interdependence and acceptance of a common com­
mitment to comprehensive patient-centered care
4. Willingness to share ideas openly and take responsibility
This chapter introduces the topic of orthotics and pros­
thetics in rehabilitation and advocates for an multi and inter­
disciplinary approach to patient-centered care. There is a
burgeoning demand for the use of orthotics and prosthet­
ics, based on the traumatic injuries sustained by U.S. service
men and women involved in military conflicts in the early
years of this century and on the projected rise in the num­
ber of persons with chronic health conditions such as obesity,
type 2 diabetes, and vascular disease. The WHO ICF is the
­current disablement framework endorsed by 191 countries.46
Rehabilitation professionals including orthotists, prosthe­
tists, physical, and occupational therapists will apply the ICF
­disablement model to maximize strategies for patient partici­
pation in the tasks of daily living through enhancement of
environmental factors such as providing appropriate, cost-
effective assistive technology including orthoses and prosthe­
ses. A rehabilitation model of patient-centered care that uses a
transdisciplinary team approach to enhance communication,
address goals and objectives, apply best practice, and improve
patient outcomes is the current standard of care for persons in
rehabilitation settings. Collaboration, mutual respect, and an
understanding of the roles and responsibilities of colleagues
engender productive teamwork and improved outcomes for
the rehabilitation patient.
REFERENCES
1. World Health Organization. International Classification of
Functioning, Disability, and Health (ICF).
classifications/icf/en/ Accessed 29.02.12.
2. Stubblefield C, Houston C, Haire-Joshu D. Interactive use of
models of health-related behavior to promote interdisciplinary
collaboration. J Allied Health. 1994;23(4):237–243.
3. Suddick KM, De Souza L. Therapists’ experiences and perceptions
of team work in neurological rehabilitation:reasoning behind the
team approach, structure and composition of the team and team­
working processes. Physiother Res Int. 2006;11(2):72–83.
4. Nenedict SM, Scholten J. The Veterans’ Health Administration's
polytrauma system of care: rehabilitation for today's and tomor­
row's veterans. J Am Soc Aging. 2010;34(2):106–108.
5. Stern S, Brault M. Disability data from the American Community
Survey: a brief examination of the effects of a question redesign in 2003.
U.S. Census Bureau, Housing and Household Economic Statistics
Division; January 28, 2005. Available at:
www/Downloads/library/2005/2005_Stern_01.pdf.
6. Limb Loss Information Centre. Surge in war amputees drives
improved prosthetic research.
com/2010/06/23/surge-in-war-amputees-drives-improved-
prosthetic-research/ Accessed 29.02.12.
7. Stagnitti M. The prevalence of obesity and other chronic condi­
tions among diabetic adults in the U.S. community population,
2001. AHRQ Statistical Brief #34.
mepsweb/data_files/publications/st34/stat34.pdf Accessed 29.02.12.
8. American Heart Association. Peripheral arterial disease.
americanheart.org Accessed 29.02.12.
9. Ziegler-Graham K, MacKenzie EJ, Ephraim PL, et al. Estimating
the prevalence of limb loss in the United States—2005 to 2050.
Arch Phys Med Rehabil. 2008;89(3):422–429.
10. U.S. Department of Labor, Bureau of Labor Statistics. Occupa­
tional Employment Statistics. Available at:
oes/current/oes292091.htm.
11. Myers RS. Historical perspective, assumptions, and ethical
considerations for physical therapy practice. In: Myers RS, ed.
Saunders Manual of Physical Therapy Practice. Philadelphia:
Saunders; 1995:3–7.
12. Shurr DG, Michael JW. Prosthetics and Orthotics. 2nd ed.
Norwalk, CT: Appleton & Lange; 2002: 1–5.
13. Retzlaff K. AOPA celebrates 75 years of service to O&P. Orthotics
and Prosthetics Almanac. 1992;(Nov):45.
14. Hazenhyer IM. A history of the American Physiotherapy
Association. Part IV: maturity, 1939-1946. Phys Ther Rev.
1946;26:174–184.
15. Wilson BA. History of amputation surgery and prosthetics. In:
Bowker JH, Michael JW, eds. Atlas of Limb Prosthetics: Surgical,
Prosthetic and Rehabilitation Principles. St. Louis: Mosby–Year
Book; 1992:3–15.
16. Mishra R. Amputation rate for U.S. troops twice that of past
wars. Boston Globe. December 9, 2004.
17. Veterans Health Administration Research Advances: Facts About
Prosthetics.
Prosthetics.pdf; January 2010 Accessed 29.02.12.
18. State of Virginia Research. Improving Veterans’ Lives. Available
at:
VAResearchApr2011.pdf; 2011 Accessed 29.02.11.
19. National Commission on Orthotic and Prosthetic Education.
List of Schools. Available at:
students/schools.asp.
20. Masala C, Donatella RP. From disablement to enablement:
­conceptual models of disability in the 20th century. Disabil
Rehabil. 2008;30(7):1233–1244.
21. Nagi S. Some conceptual issues in disability and rehabilitation.
In: Sussman M, ed. Sociology and Rehabilitation. Washington,
DC: American Sociological Association; 1965:100–113.
22. Bornman J. The World Health Organisation's terminology and
classification: application to serve disability. Disabil Rehabil.
2004;26(3):182–188.
23. Rimmer J. Use of the ICF in identifying factors that impact
­participation in physical activity/rehabilitation among people
with disabilities. Disabil Rehabil. 2006;28(17):1087–1095.
24. International Classification of Impairments, Disability, and
Handicaps.
dda-mnc-c03.pdf; 1980 Accessed 29.02.12.
25. Nagi SZ. Disability concepts revisited: implications for pre­
vention. In: Pope AM, Tarlov AR, eds. Institute of Medicine
Disability in America: Toward a National Agenda for Prevention.
Washington, DC: National Academy Press; 1991.
26. World Health Organization. Towards a Common Language
for Functioning, Disability and Health. Geneva: World Health
Organization; 2002.
27. Cooper BS, Fishman EF. The Interdisciplinary Team in the
Management of Chronic Conditions: Has Its Time Come?
Partnerships for Better Solutions, In Retooling for an Aging
America: Building the Health Care Workforce. Washington, DC:
The National Academies Press; 2008.
28. Hall P, Weaver L. Interdisciplinary education and teamwork: a
long and winding road. Med Educ. 2001;35(9):867–875.

Chapter 1  Orthotics and Prosthetics in Rehabilitation: Multidisciplinary Approach
13
29. Sackett DL, Strauss SE, Richardson WS, et  al. Evidence-based
Medicine. 2nd ed. Toronto: Churchhill Livingston; 2000.
30. Strasser DC, Falconer JA, Martino-Saltzmann D. The reha­
bilitation team: staff perceptions of the hospital environment,
the interdisciplinary team environment, and interprofessional
­relations. Arch Phys Med Rehabil. 1994;75(2):177–182.
31. Alexander JA, Lichtenstein R, Jinnet K, et al. The effects of treat­
ment team diversity and size on assessment of team functioning.
Hospital Health Serv Admin. 1996;41(1):37.
32. Oxford Dictionary Online.
definition/team?region=US$q=team.
33. Pearson P, Jones K. The primary health care non-team? Dynamics
of multidisciplinary provider groups. BMJ. 1994;309(6966):
1387–1388.
34. Hackman JR. Groups That Work (& Those That Don't): Creating
Conditions for Effective Team Work. San Francisco: Jossey-Bass; 1990.
35. Goodman PS, Devadas RA, Hughson TLG. Groups and produc­
tivity: analyzing the effectiveness of self-managing teams. In:
Campbell JP, Campbell JR, eds. Productivity in Organizations.
San Francisco: Jossey-Bass; 1988:295–327.
36. Van Norman G. Interdisciplinary Team Issues. Ethics in Medicine.
Available at:
html; 2008 Accessed 29.02.12.
37. Fried B, Rundall T. Group and teams in health services orga­
nizations. In: Shortell SM, Kaluzny AD, eds. Health Care
Management, Organization, Design and Behavior. 3rd ed. Albany,
NY: Delmar; 1994.
38. Area Health Education Center, DC. Models of Team Practice-
Interdisciplinary Health Care Team Practice. Available at:

Accessed 29.02.12.
39. Lopopolo RB. The relationship of role-related variable to job
­satisfaction and commitment to the organization in a restruc­
tured hospital environment. Phys Ther. 2002;82(10):984–999.
40. Nielsen CC. Factors affecting the use of prosthetic services.
J Prosthet Orthot. 1989;1(4):242–249.
41. Nielsen CC. A survey of amputees: functional level and life sat­
isfaction, information needs, and the prosthetist's role. J Prosthet
Orthot. 1991;3(3):125–129.
42. Banta JV, Lin RS, Peterson M, et al. The team approach in the child
with myelomeningocele. J Prosthet Orthot. 1990;2(4):365–375.
43. Wiart L, Darrah J. Changing philosophical perspectives on the
management of children with physical disabilities: their effect
on the use of powered mobility. Disabil Rehabil. 2002;24(9):
492–498.
44. Michael J. Pediatric prosthetics and orthotics. Phys Occup Ther
Pediatr. 1990;10(2):123–146.
45. U.S.Department of Education. Individuals with Disabilities
Education Act. Accessed 2.02.12.
46. World Health Organization. International Classification of
Functioning, Disability and Health. Available at:
who.int/classifications/icf/en/ Accessed 15.02.11.

14
2
Aging and Activity Tolerance:
Implications for Orthotic and Prosthetic Rehabilitation
Kevin K. Chui and Michelle M. Lusardi
Many individuals who rely on orthotic or prosthetic
devices in order to walk or to accomplish functional tasks
have impairments of the musculoskeletal or neuromuscu­
lar ­systems that limit the efficiency of their movement and
increase the energy cost of their daily and leisure activi­
ties. The separate and interactive effects of aging, inactivity,
and cardiac or pulmonary disease can also compromise the
capacity for muscular “work,” tolerance of activity, and ability
to function.
Consider this example: a 79-year-old woman with
insulin-controlled type 2 diabetes has been referred for
physical therapy evaluation after transfemoral amputation
following a failed femoral-popliteal bypass. She has been on
bed rest for several weeks because of her multiple surgeries.
The physical effort required by rehabilitation and prosthetic
training may initially feel overwhelming to this woman. In
her deconditioned state, preprosthetic ambulation with a
walker is likely to increase her heart rate (HR) close to the
upper limits of a safe target HR for aerobic training. What,
then, is her prognosis for functional use of a prosthesis? What
are the most important issues to address in her plan of care?
What ­intensity of intervention is most appropriate given
her deconditioned state? In what setting and for how long
will care be provided? These are questions without simple
answers.
The physical therapist, orthotist, and prosthetist must
­recognize factors that can be successfully modified to enhance
performance and activity tolerance when making decisions
about prescription and intervention strategies. Aerobic ­fitness
should be a key component of the rehabilitation program for
those who will be using a prosthesis or orthosis for the first
time. It is vitally important that rehabilitation professionals
recognize and respond to the warning signs of significant car­
diopulmonary or cardiovascular dysfunction during treat­
ment and training sessions.
Although the anatomical and physiological changes in the
aging cardiopulmonary system are important to our discus­
sion, our focus is on the contribution of cellular and tissue-
level changes to performance of the cardiopulmonary and
cardiovascular systems and, subsequently, on the individual's
ability to function. This view provides a conceptual frame­
work for answering four essential questions:
• Is this individual capable of physical work?
• If so, what is the energy cost of doing this work?
• Is it possible for this individual to become more efficient
or more able to do physical work?
• What impact does the use of an orthosis or prosthesis have
on energy use and cost during functional activities for this
person?
OXYGEN TRANSPORT SYSTEM
The foundation for the functional view of the cardiopulmo­
nary system is the equation for the oxygen transport system
(Figure 2-1). Aerobic capacity (VO2max) is the body's ability to
deliver and use oxygen (maximum rate of oxygen consump­
tion) to support the energy needs of demanding physical
activity. VO2max is influenced by three factors: the efficiency
of ventilation and oxygenation in the lungs, how much
oxygen-rich blood can be delivered from the heart (cardiac
output, or CO) to active peripheral tissues, and how well
2
LEARNING OBJECTIVES
On completion of this chapter, the reader will be able to do
the following:
1. Describe the role of the cardiopulmonary and cardio­
vascular systems as “effectors” for goal-driven functional
motor activity.
2. Define the key components of cardiopulmonary and car­
diovascular systems as they relate to energy expenditure
during functional activity.
3. Describe the functional consequences of age-related
change in cardiopulmonary and cardiovascular structures,
especially with respect to exercise and activity tolerance.
4. Apply principles of cardiopulmonary/cardiovascular con­
ditioning to rehabilitation interventions for older or decon­
ditioned individuals, or both, who will be using a prosthesis
or an orthosis.
5. Weigh the benefits and limitations, with respect to energy
cost and facilitation of daily function, in selecting an
appropriate orthosis or prosthesis for an older or decondi­
tioned individual.

Chapter 2  Aging and Activity Tolerance: Implications for Orthotic and Prosthetic Rehabilitation
15
oxygen is extracted from the blood to support muscle con­
traction and other peripheral tissues during activity (arterial-
venous ­oxygen difference, or AVO2diff).1–3 Aerobic capacity
can be represented by the following formula:
=
×
2max
2diff
VO
CO
AVO
The energy cost of doing work is based on the amount
of oxygen consumed for the activity, regardless of whether
the activity is supported by aerobic (with oxygen) or anaer­
obic (without oxygen) metabolic mechanisms for produc­
ing energy. VO2max provides an indication of the maximum
amount of work that can be supported.1–3
CO is the product of two elements. The first is the HR,
the number of times that the heart contracts, or beats, per
minute. The second is stroke volume (SV), the amount
of blood pumped from the left ventricle with each beat
(measured in milliliters or liters). Cardiac output is
expressed by the following formula (measured in milliliters
or liters per minute):
As a product of HR and SV, CO is influenced by four fac­
tors: (1) the amount of blood returned from the periphery
through the vena cava, (2) the ability of the heart to match its
rate of contraction to physiological demand, (3) the efficiency
or forcefulness of the heart's contraction, and (4) the ability of
the aorta to deliver blood to peripheral vessels. The delivery
of oxygen to the body tissues to be used to produce energy for
work is, ultimately, a function of the central components of
the cardiopulmonary system.1–3
The second determinant of aerobic capacity, the AVO2diff,
reflects the extraction of oxygen from the capillary by the
­surrounding tissues. The AVO2diff is determined by subtract­
ing the oxygen concentration on the venous (postextraction)
side of the capillary bed (CvO2) from that of the arteriole
(preextraction) side of the capillary bed (CaO2), according to
the formula:
The smaller vessels and capillaries of the cardiovascu­
lar system are involved in the process of extraction of oxy­
gen from the blood by the active tissues. Extraction of oxygen
from the blood to be used to produce energy for the work of
the active tissues is a function of the peripheral components
of the cardiopulmonary system.1–3
During exercise or a physically demanding activity, CO
must increase to meet the need for additional oxygen in the
more active peripheral tissues. This increased CO is the result
of a more rapid HR and a greater SV: As the return of blood
to the heart increases, the heart contracts more forcefully and
a larger volume of blood is pumped into the aorta by the left
ventricle. Chemical and hormonal changes that accompany
exercise enhance peripheral shunting of blood to the active
muscles, and oxygen depletion in muscle assists transfer of
oxygen from the capillary blood to the tissue at work.3,4
The efficiency of central components, primarily of CO,
accounts for as much as 75% of VO2max. Peripheral oxygen
extraction (AVO2diff) contributes the remaining 25% to the
process of making oxygen available to support tissue work.5
In healthy adults, under most conditions, more ­oxygen is
=
×
CO
HR
SV
=
−
2diff
2
2
AVO
CaO
CvO
Lungs
Heart
Aorta
O2
exchange
Capillary bed
Arteries & arterioles
Veins & venules
Vena cava
Left atrium
Left ventricle
Right ventricle Right atrium
Mitral valve
Tricuspid valve
Pulmonic
valve
Aortic
valve
Pulmonary
vein
Pulmonary
artery
Central
Peripheral
Delivery
Oxygenation
Extraction
CO2
exchange
Work Capacity: VO2max  CO  AVO2diff
(HR  SV)  (CaO2  CvO2)
FIGURE  2-1  Functional anatomy and physiology of the cardiorespiratory system. After blood is
oxygenated in the lungs, the left side of the heart contracts to deliver blood, through the aorta and
its branches, to active tissues in the periphery. Oxygen must be effectively extracted from blood by
peripheral tissues to support their activity. Deoxygenated blood, high in carbon dioxide, returns
through the vena cava to the right side of the heart, which pumps it to the lungs for reoxygenation.
Aerobic capacity (VO2max) is the product of how well oxygen is delivered to cardiac output (CO) and
extracted by arterial-venous oxygen difference (AVO2diff) active tissues. HR, Heart rate; SV, stroke
volume.

16
Section I  Building Baseline Knowledge
delivered to active tissues (muscle mass) than is necessary.3,5
For those who are significantly deconditioned or who have
­cardiopulmonary or cardiovascular disease, the ability to
deliver oxygen efficiently to the periphery as physical activ­
ity increases may be compromised. With normal aging, there
are age-related physiological changes in the heart itself that
limit maximum attainable HR. Because of these changes, it
is important to assess whether and to what degree SV can be
increased effectively if rehabilitation interventions are to be
successful.
THE AGING HEART
The ability to plan an appropriate intervention to address
cardiovascular endurance and conditioning in older adults
who may need to use a prosthesis or orthosis is founded on
an understanding of “typical” age-related changes in cardio­
vascular structure and physiology, as well as on the functional
consequences of these changes.
Cardiovascular Structure
Age-related structural changes in the cardiovascular sys­
tem occur in five areas: myocardium, cardiac valves, coro­
nary arteries, conduction system, and coronary vasculature
(i.e., arteries)6–9 (Table 2-1). Despite these cellular and tissue
level changes, a healthy older heart can typically meet energy
demands of usual daily activity. Cardiovascular disease, quite
prevalent in later life, and a habitually sedentary lifestyle can,
however, significantly compromise activity tolerance.10
Myocardium
With advanced age, cells of the myocardium show micro­
scopical signs of degeneration including increases in myo­
cardial fat content (i.e., storage of triglyceride droplets
within cardiomyocytes); however, the relationship between
the quantity of fat and disease severity remains unclear.11
Unlike aging skeletal muscle cells, there is minimal atro­
phy of cardiac smooth muscle cells. More typically, there is
hypertrophy of the left ventricular myocardium, increasing
the diameter of the left atrium.12–14 These changes have been
attributed to cardiac tissue responses to an increased systolic
blood pressure (SBP) and to reduced compliance of the left
ventricle and are associated with an increase in weight and
size of the heart.13–17
Valves
The four valves of the aged heart often become fibrous and
thickened at their margins, as well as somewhat calcified.18
Calcification of the aorta at the base of the cusps of the aortic
valve (aortic stenosis) is clinically associated with the slowed
exit of blood from the left ventricle into the aorta.19 Such
aortic stenosis contributes to a functional reduction in CO.
A baroreflex-mediated increase in SBP attempts to compen­
sate for this reduced CO.20,21 Over time, the larger residual
of blood in the left ventricle after each beat (increased end
systolic volume, or ESV) begins to weaken the left ventric­
ular muscle.22 The left ventricular muscle must work harder
to pump the blood out of the ventricle into a more resistant
peripheral vascular system.23,24
Calcification of the annulus of the mitral valve can restrict
blood flow from the left atrium into the left ventricle during
diastole. As a result, end diastolic volume (EDV) of blood in
the left ventricle is decreased because the left atrium does not
completely empty. Over time, this residual blood in the left
atrium elongates the muscle of the atrial walls and increases
the diameter of the atrium of the heart.23–25
Coronary Arteries
Age-related changes of the coronary arteries are similar to
those in any aged arterial vessel: an increase in thickness of
vessel walls and tortuosity of its path.26 These changes tend
to occur earlier in the left coronary artery than in the right.27
TABLE 2-1  Age-Related Changes in the Cardiovascular System
Structure
Change
Functional Consequences
Heart
Deposition of lipids, lipofuscin, and amyloid
within cardiac smooth muscle
Increased connective tissue and fibrocity
Hypertrophy of left ventricle
Increased diameter of atria
Stiffening and calcification of valves
Fewer pacemaker cells in sinoatrial and atrioventricular nodes
Fewer conduction fibers in bundle of His and branches
Less sensitivity to extrinsic (autonomic) innervation
Slower rate of tension development during contraction
Less excitability
Diminished cardiac output
Diminished venous return
Susceptibility to dysrhythmia
Reduction in maximal attainable heart rate
Less efficient dilation of cardiac arteries during activity
Less efficient left ventricular filling in early diastole,
leading to reduced stroke volume
Increased afterload, leading to weakening of heart
muscle
Blood vessels




Altered ratio of smooth muscle to connective
tissue and elastin in vessel walls
Decreased baroreceptor responsiveness
Susceptibility to plaque formation within vessel
Rigidity and calcification of large arteries, especially aorta
Dilation and increased tortuosity of veins
Less efficient delivery of oxygenated blood to muscle
and organs
Diminished cardiac output
Less efficient venous return
Susceptibility to venous thrombosis
Susceptibility to orthostatic hypotension

Chapter 2  Aging and Activity Tolerance: Implications for Orthotic and Prosthetic Rehabilitation
17
When coupled with atherosclerosis, these changes may com­
promise the muscular contraction and pumping efficiency
and effectiveness of the left ventricle during exercise or
­activity of high physiological demand.2,3,28
Conduction System
Age-related changes in the conduction system of the heart
can have a substantial impact on cardiac function. The ­typical
75-year-old has less than 10% of the original number of
pacemaker cells of the sinoatrial node.29,30 Fibrous tissue
builds within the internodal tracts as well as within the
atrioventricular node, including the bundle of His and its
main bundle branches.29,30 As a consequence, the ability of
the heart to coordinate the actions of all four of its cham­
bers may be compromised.29 Arrhythmias are pathological
conditions that become more common in later life; they are
managed pharmacologically or with implantation of a pace­
maker/defibrillator.31 Rehabilitation professionals must be
aware of the impact of medications or pacemaker settings
on an individual's ­ability to physiologically respond to exer­
cise and to adapt to the intervention, whether it be a condi­
tioning program or early mobility after a medical/surgical
event, accordingly.32
Arterial Vascular Tree
Age-related changes in the arterial vascular tree, demon­
strated most notably by the thoracic aorta and eventually
the more distal vessels, can disrupt the smooth or stream­
line flow (i.e., laminar flow) of blood from the heart toward
the periphery.31,33 Altered alignment of endothelial cells of
the intima creates rough or turbulence flow (i.e., nonlaminar
flow), which increases the likelihood of deposition of colla­
gen and lipid.34 Fragmentation of elastic fibers in the intima
and media of larger arterioles and arteries further compro­
mises the functionally important “rebound” characteristic of
arterial vessels.35 Rebound normally assists directional blood
flow through the system, preventing the backward reflec­
tion of fluid pressure waves of blood. This loss of elasticity
increases vulnerability of the aorta, which, distended and
stiffened, cannot effectively resist the tensile force of left ven­
tricular ejection. Not surprisingly, the incidence of abdomi­
nal aortic aneurysms rises sharply among older adults, and
stiffness (distensibility) of the ascending aorta is associated
with severity of coronary artery disease.36,37
Cardiovascular Physiology
Although the physiological changes in the cardiovascular
system are few, their impact on performance of the older
adult can be substantial. The nondiseased aging heart con­
tinues to be an effective pump, maintaining its ability to
develop enough myocardial contraction to support daily
activity. The response of cardiac muscle to calcium (Ca++)
is preserved, and its force-generating capacity maintained.38
Two aspects of myocardial contractility do, however, change
with aging: the rate of tension development in the myocar­
dium slows and the duration of contraction and relaxation is
prolonged.39,40
Sensitivity Beta-Adrenergic
One of the most marked age-related changes in cardiovascular
function is the reduced sensitivity of the heart to sympathetic
stimulation, specifically to the stimulation of beta-adrenergic
receptors.40,41 Age-related reduction in beta-adrenergic sen­
sitivity includes a decreased response to norepinephrine
and epinephrine released from sympathetic nerve end­
ings in the heart, as well as a decreased sensitivity to any of
these catecholamines circulating in the blood.41,42 Normally,
norepinephrine and epinephrine are potent stimulators of
ventricular contraction.
An important functional consequence of the change
in receptor sensitivity is less efficient cardioacceleratory
response, which leads to a lower HR at submaximal and
maximal levels of exercise or activity.43 The time for HR
rise to the peak rate is prolonged, so more time is necessary
to reach the appropriate HR level for physically demand­
ing activities. A further consequence of this reduced beta-
adrenergic sensitivity is less than optimal vasodilation of the
coronary arteries with increasing activity.41,44 In peripheral
arterial vessels, beta-adrenergic receptors do not appear to
play a primary role in mediating vasodilation in the working
muscles.45
Baroreceptor Reflex
Age-related change in the cardiovascular baroreceptor
reflex also contributes to prolongation of cardiovascular
response time in the face of an increase in activity (physi­
ological demand).40 The baroreceptors in the proximal aorta
appear to become less sensitive to changes in blood volume
(pressure) within the vessel. Normally, any drop in proxi­
mal aortic pressure triggers the hypothalamus to begin a
sequence of events that leads to increased sympathetic stim­
ulation of the heart. Decreased baroreceptor responsiveness
may increase an older individual's susceptibility to ortho­
static (postural) and postprandial (after eating) hypoten­
sion, or compromise their tolerance of the physiological
stress of a Valsalva maneuver associated with breath hold­
ing during strenuous activity.46,47 Clinically, this is evidenced
by lightheadedness when rising from lying or sitting, espe­
cially after a meal, or if one tends to hold one's breath during
effortful activity.
The consequences of age-related physiological changes
on the cardiovascular system can often be managed effec­
tively by routinely using simple lower extremity warmup
exercises before position changes. Several repetitions of
ankle and knee exercises before standing up, especially
after a prolonged time sitting (including for meals) or lying
down (after a night's rest), help maximize blood return to
the heart (preload), assisting cardiovascular function for the
impending demand. In addition, taking a bit more time in
initiating and progressing difficulty of activities may help
the slowed cardiovascular response time reach an effective
level of performance. Scheduling physical therapy or physi­
cal activity remote from mealtimes might also be beneficial
for patients who are particularly vulnerable to postprandial
hypotension.

18
Section I  Building Baseline Knowledge
Functional Consequences of Cardiovascular Aging
What are the functional consequences of cardiovascular aging
for older adults participating in exercise or rehabilitation
activities? This question can best be answered by focusing on
what happens to the CO (Figure 2-2). The age-related struc­
tural and physiological changes in the cardiovascular system
give rise to two loading conditions that influence CO: cardiac
filling (preload) and vascular impedance (afterload).3,20
Preload
Cardiac filling/preload determines the volume of blood in the
left ventricle at the end of diastole. The most effective ventricular
filling occurs when pressure is low within the heart and relax­
ation of the muscular walls of the ventricle is maximal.1,5 Mitral
valve calcification, decreased compliance of the left ventricle, and
the prolonged relaxation of myocardial contraction can contrib­
ute to a less effective filling of the left ventricle in early diastole.48
Doppler studies of the flow of blood into the left ventricle in aging
adults demonstrate decreased rates of early filling, an increased
rate of late atrial filling, and an overall decrease in the peak filling
rate.5,22,48 When compared with healthy 45- to 50-year-old adults,
the early diastolic filling of a healthy 65- to 80-year-old is 50%
less.5,22,49 This reduced volume of blood in the ventricle at the end
of diastole does not effectively stretch the ventricular muscle of
the heart, compromising the Frank-Starling mechanism and the
myocontractility of the left ventricle.50 The functional outcome
of decreased early diastolic filling and the reduced EDV is a pro­
portional decrease in SV, one of the determinants of CO and,
subsequently, work capacity (VO2max).5,21,40
Afterload
High vascular impedance and increased afterload disrupts flow
of blood as it leaves the heart toward the peripheral vascula­
ture. Increased afterload is, in part, a function of age-related
stiffness of the proximal aorta, an increase in systemic vas­
cular resistance (elevation of SBP, hypertension), or a combi­
nation of both factors.40,51 Ventricular contraction that forces
blood flow into a resistant peripheral vascular system produces
pressure waves in the blood. These pressure waves reflect back
toward the heart, unrestricted by the stiffened walls of the
proximal aorta. The reflected pressure waves, aortic stiffness,
and increased systemic vascular resistance collectively contrib­
ute to an increased afterload in the aging heart.39,51 Increased
afterload is thought to be a major factor in the age-associated
decrease in maximum SV, hypertrophy of the left ventricle, and
prolongation of myocardial relaxation (e.g., slowed relaxation
in the presence of a persisting load on the heart).6,7,9
An unfortunate long-term consequence of increased
afterload is weakening of the heart muscle itself, particularly
of the left ventricle. Restricted blood flow out of the heart
results in a large residual volume (RV) of blood in the heart
at the end of systole when ventricular contraction is com­
plete. Large ESVs gradually increase the resting length of
ventricular cardiac muscle, effectively weakening the force
of contraction.2,6,7,9,22,52
Left Ventricular Ejection Fraction
Left ventricular ejection fraction (LVEF) is the proportion of
blood pumped out of the heart with each contraction of the
left ventricle, which is expressed by the following equation:
At rest the LVEF does not appear to be reduced in older
adults. Under conditions of maximum exercise, however,
the rise in LVEF is much less than in younger adults.21,53,54
This reduced rise in the LVEF with maximal exercise clearly
illustrates the impact that preload and afterload functional
cardiovascular age-related changes have on performance.
A substantial reduction in EDV, an expansion of ESV, or
a more modest change in both components may account for
the decreased LVEF of the exercising older adult:
When going from resting to maximal exercise condi­
tions, the amount of blood pumped with each beat for young
healthy adults increases 20% to 30% from a resting LVEF of
55% to an exercise LVEF of 80%. For a healthy older adult,
in contrast, LVEF typically increases less than 5% from rest
to maximal exercise.53,55 The LVEF may actually decrease in
adults who are 60 years of age and older.53,56 As LVEF and
CO decrease with aging, so does the ability to work over
prolonged periods (functional cardiopulmonary reserve
capacity) because the volume of blood delivered to active
tissue decreases (Figure 2-3). Functional reserve capacity
is further compromised by the long-term effects of inactiv­
ity and by cardiopulmonary pathology.21,28,57,58 The contri­
bution of habitual exercise to achieving effective maximum
exercise LVEF is not well understood but the decline may
not be as substantial for highly fit older adults.21
PULMONARY FUNCTION IN LATER LIFE
Several important age-related structural changes of the lungs
and of the musculoskeletal system have a significant impact
on pulmonary function.59 These include change in the tis­
sues and structures making up the lungs and airways, alter­
ation in lung volume, reduced efficiency of gas exchange,
and a mechanically less efficient ventilatory pump related
=
−
÷
LVEF
(EDV
ESV)
EDV
↓
= ↓
↑
= ↓
EDV
LVEF
ESV
LVEF
CARDIAC
OUTPUT
Strength of
contraction
End diastolic
volume
Stroke
volume
Heart
rate
Instrinsic
rhythmicity
Autonomic
regulation
FIGURE 2-2  Factors affecting cardiac output are influenced by the
aging process: If strength of contraction decreases and end diastolic
volume increases, stroke volume is reduced. Coupled with altera­
tions in heart rate response to increasing workload, activities that
were submaximal in intensity at a younger age may become more
physiologically demanding in later life.

Chapter 2  Aging and Activity Tolerance: Implications for Orthotic and Prosthetic Rehabilitation
19
to changes in alignment and posture60 (Table 2-2). Although
a healthy adult at midlife uses only 10% of the respiratory
system capacity at rest, aging of the pulmonary system,
especially when accompanied by chronic illness or acute dis­
ease, negatively affects the ability of the lungs to respond to
increasing demands of physical activity61 (Figure 2-4). Age-
related changes in the pulmonary and musculoskeletal sys­
tems also contribute to an increase in the physiological work
of breathing.
Changes within the Lung and Airway
The production of elastin, which is the major protein compo­
nent of the structure of the lungs, decreases markedly in late
life. The elastic fibers of the lung become fragmented, and,
functionally, the passive elastic recoil or rebound important
for expiration becomes much less efficient. The elastic fibers
that maintain the structure of the walls of the alveoli also
decrease in number. This loss of elastin means loss of alveoli
and consequently less surface area for the exchange of oxy­
gen, as well as an increase in RV associated with more “dead
space” within the lung where air exchange cannot occur.60,61
TABLE 2-2  Summary of Age-Related Changes in the Cardiopulmonary System and Functional Consequences
Anatomical Changes
Physiological Changes
Consequences
Change in Lung Function Tests
Rearrangement and
fragmentation of elastin fibers
Stiffened cartilage in compliant
articulation of ribs and
vertebrae
Increasing stiffness and
compression of annulus
fibrosis in intervertebral disks
Reduction of strength and
endurance of respiratory
musculature
Less elastic recoil for
expiration
Greater compliance of lung
Decreased vital capacity, forced
More rigid thoracic cage
Decreased volume of
maximum voluntary
ventilation and maximum
sustained ventilatory capacity
Greater mismatch between
ventilation and perfusion
within lung
Greater airspace within
alveoli, less surface area for
O2/CO2 exchange thoracic
cage
Increased work of breathing
Less force during inspiration
Less efficient cough
Diminished exercise tolerance
Reduced resting PaO2


Increased functional residual capacity
and residual volume tissue
Shorter, less vital capacity, and forced
expiratory volume in 1 second (FEV1)
Decreased maximum inspiratory
pressure, maximum expiratory
pressure, and maximum voluntary
ventilation



TLC
TLC
IRV
IRV
TV
TV
ERV
ERV
RV
RV
RV
RV
FVC
FVC
Young adults
Older adults
6
5
4
3
2
1
0
Volume in liters
FIGURE  2-4  Changes in the distribution of air within the lungs
(­volume) have an impact on an older adult's efficiency of physical
work. Loss of alveoli and increasing stiffness of the rib cage result in
a 30% to 50% increase in residual volume (RV) and a 40% to 50%
decrease in forced vital capacity (FVC). FVC includes three compo­
nents: Inspiratory reserve volume (IRV) and expiratory reserve volume
(ERV) tend to decrease with aging, whereas resting tidal volume (TV),
the amount of air in a normal resting breath, tends to be stable over
time. Total lung capacity (TLC) and inspiratory capacity (IRV + TV)
also tend to decrease. Over time, the physiological consequences of
these changes make the older adult more vulnerable to dyspnea (short­
ness of breath) during exercise and physically demanding activity.
Healthy
young
adult
Healthy
older
adult
Sedentary
older
adult
Older
adult with
disease
ADLs
At rest
Reserve
capacity
Reserve
capacity
Reserve
capacity
Reserve
capacity
Age-related
loss
Impact of
inactivity
Impact of
disease
Age-related
loss
Age-related
loss
Impact of
inactivity
ADLs
ADLs
ADLs
At rest
At rest
At rest
FIGURE 2-3  Comparison of the effects of aging, inactivity, and car­
diopulmonary disease on functional reserve capacity, expressed as
cardiac output (CO in L/min). At rest, the heart delivers between
4 and 6 L/min of blood to peripheral tissues. This may double dur­
ing many activities of daily living. In a healthy young person, the CO
may increase to as much as 24 L/min to meet metabolic demands of
sustained exercise. This reserve capacity decreases to approximately
18 L/min in healthy, fit adults after the age of 60 years. A sedentary
lifestyle decreases functional reserve capacity further. Superimposed
cardiopulmonary disease further limits the ability to do physical work,
in some cases approaching or exceeding cardiopulmonary reserve
capacity. (Modified from Irwin SC, Zadai CC. Cardiopulmonary
rehabilitation of the geriatric patient. In Lewis CB [ed], Aging: The
Health Care Challenge. Philadelphia: F.A. Davis, 1990. p. 190.)

20
Section I  Building Baseline Knowledge
There may be as much as a 15% decrease in the total number
of alveoli per unit of lung volume by the age of 70 years.62
With aging, there is also an increase in diameter of major
bronchi and large bronchioles, as well as a decreased diameter
of smaller bronchioles, often leading to a slight increase in
resistance to air flow during respiration.62 This contributes to
greater physical work to breathe as age advances.
Starting at midlife and continuing into later life, there tends
to be a growing mismatch between lung area ventilated with
each breath and lung area perfused by pulmonary arterioles
and capillaries, attributed to alteration in alveolar surface, vas­
cular structures, and posture.63 This mismatch compromises
the efficiency of diffusion of oxygen across the alveoli into the
capillary bed (i.e., decreasing arterial oxygen tension) within
the lung becomes less efficient from midlife into later life.60,63
Changes in the Musculoskeletal System
The decreasing elastic recoil and alveolar surface area for oxy­
gen exchange may be further compounded by increased stiff­
ness (loss of flexibility), “barreling” of the thoracic rib cage that
houses the lungs, and a decrease in height as intervertebral
disks narrow and stiffen.64 Much of the stiffness is attributed to
changes in the articulation between rib and vertebrae, as well
as decreased elasticity of intercostal muscle and soft tissue.65
Although the stiffened rib cage may be as much a consequence
of a sedentary lifestyle as of advancing age, lack of flexibility
compromises inspiration and also decreases elastic recoil of
expiration.66 In addition, the forward head and slight kyphosis
that tend to develop with aging alter rib and diaphragm posi­
tion, decreasing mechanical efficiency of inspiration.61,64,66 The
net effect of a stiffer thoracic cage is an increase in the work of
taking a breath since muscles of respiration must work harder
during inspiration to counteract the stiffness.61
The striated muscles of respiration are composed of a combi­
nation of type I (slow twitch, fatigue resistant, for endurance) and
type II (fast twitch, for power) fibers and are susceptible to the
same age-related changes in strength and endurance that have
been observed in muscles of the extremities.67 Normally, type I
muscle fibers are active during quiet breathing while recruitment
of type II fibers is triggered by increasing physiological demand
as activity increases. Age-related decrement in the strength and
efficiency of the diaphragm, intercostals, abdominal muscles,
and other accessory muscles of respiration affects the effective­
ness and work of breathing.61,68 Altered posture and higher RV
within the lung also contribute to an increased work of breath­
ing; when the diaphragm rests in less than optimal position and
configuration for contraction, accessory muscles become active
sooner, as physiological demand increases. Oxygen consump­
tion in respiratory muscles, as in all striated muscle, decreases
linearly with age, making older muscle more vulnerable to the
effects of fatigue in situations of high physical demand, especially
in the presence of lung disease or injury.60
Control of Ventilation
The rate of breathing (breaths per minute) is matched to
physiological demand by input from peripheral mechanore­
ceptors in the chest wall, lungs, and thoracic joints, as well as
centers in the brainstem of central nervous systems (CNS)
and peripheral aortic and carotid bodies that are sensitive
to concentration of CO2, O2, and hydrogen ions (pH) in the
blood.69 With aging, stiffness of the thorax tends to reduce
efficiency of mechanoreceptors, and the CNS and peripheral
nervous system (PNS) centers that monitor CO2, O2, and pH
to detect hypoxia during activity slowly begin to decline.
Gradual loss of descending motor neurons within the CNS
also occurs, with less efficient activation of neurons innervat­
ing muscles of respiration via the phrenic nerve to the dia­
phragm for inspiration and of spinal nerves to intercostals
for expiration.63 These three factors combine to compromise
the individual's ability to quickly and accurately respond to
increasing physiological demand and increase the likelihood
of dyspnea during activity.
Functional Consequences of Pulmonary Aging
With less recoil for expiration and reduced flexibility for
inspiration, the ability to work is compromised in two ways
(see Figure  2-4). First, vital capacity (VC), the maximum
amount of air that can be voluntarily moved in and out of
the lungs with a breath, is decreased by 25% to 40%. Second,
RV, the air remaining in the lungs after a forced expiration,
is increased by 25% to 40%.60 This combination of reduced
movement of air with each breath and increased air remain­
ing in the lung between breaths leads to higher lung-air car­
bon dioxide content and, eventually, lower oxygen saturation
of the blood after air exchange. The increase in RV also affects
the muscles of inspiration: the dome of the diaphragm flat­
tens and the accessory respiratory muscles are elongated.
As a result of these length changes, the respiratory muscles
work in a mechanically disadvantageous range of the length-
tension curve, and the energy cost of the muscular work of
breathing rises.61
Functionally, the amount of air inhaled per minute (min­
ute ventilation) is a product of the frequency of breathing
times the tidal volume (volume of air moving into and out
of the lungs with each usual breath). In healthy individu­
als, the increased ventilatory needs of low-intensity activi­
ties are usually met by an increased depth of breathing (i.e.,
increased tidal volume).70 Frequency of breathing increases
when increased depth alone cannot meet the demands of
activity, typically when tidal volume reaches 50% to 60% of
the VC.70 For the older adult with reduced VC who is involved
in physical activity, tidal volume can quickly exceed this level,
so that frequency of breathing increases much earlier than
would be demonstrated by a young adult at the same inten­
sity of exercise.71 Because the energy cost of breathing rises
sharply with the greater respiratory muscle work associated
with an increased respiratory rate, an important consequence
of increased frequency of breathing is fatigue.72 This early
reliance on an increased frequency of breathing, combined
with a large RV and its higher carbon dioxide concentration
in lung air, results in a physiological cycle that further drives
the need to breathe more frequently. Overworked respiratory
muscles are forced to rely on anaerobic metabolism to sup­
ply their energy need, resulting in a buildup of lactic acid.

Chapter 2  Aging and Activity Tolerance: Implications for Orthotic and Prosthetic Rehabilitation
21
Because lactic acid lowers the pH of the tissues (acidosis), it is
also a potent physiological stimulus for increased frequency
of breathing.72–74 The older person can be easily forced into
a condition of rapid, shallow breathing (shortness of breath)
to meet the ventilatory requirements of seemingly moderate-
intensity exercise.
IMPLICATIONS FOR INTERVENTION
Rehabilitation professionals must consider two questions about
the implications of age-related changes in the cardiovascular
and cardiopulmonary systems on an older person's ability to
do physical work. First, what precautions should be observed
to avoid cardiopulmonary and cardiovascular complications?
Second, what can be done to optimize cardiopulmonary and
cardiovascular function for maximal physical performance?
Precautions
Because of the combined effects of the age-related changes
in the cardiovascular and cardiopulmonary systems, the
high incidence of cardiac and pulmonary pathologies in
later life, and the deconditioning impact of bed rest and
inactivity, older patients who require orthotic or prosthetic
intervention may be vulnerable if exercise or activity is too
physiologically demanding. Although most older adults can
tolerate and respond positively to exercise, exercise is not
appropriate in a number of circumstances (Table 2-3).
Estimating Workload: Heart Rate and Rate Pressure
Product
One of the readily measurable consequences of the reduced
response of the heart to sympathetic stimulation in later life is a
reduction in the maximal attainable HR.39,69,75 This reduction in
TABLE 2-3  Signs and Symptoms of Exercise Intolerance
Category
Cautionary Signs/Symptoms
Contraindications to Exercise
Heart rate
< 40 bpm at rest
> 130 bpm at rest
Little HR increase with activity
Excessive HR increase with activity
Frequent arrhythmia
Prolonged at maximum activity
ECG
Any recent ECG abnormalities
Prolonged arrhythmia or tachycardia
Exercise-induced ECG abnormalities
Third-degree heart block
Blood pressure
Resting SBP >165 mm Hg
Resting DBP >110 mm Hg
Lack of SBP response to activity
Excessive BP response to activity
Resting SBP >200 mm Hg
Resting DBP >110 mm Hg
Drop in SBP >20 mm Hg in exercise
Drop in DBP during exercise
Angina
Low threshold for angina
Resting or unstable angina
New jaw, shoulder, or left arm pain
Respiratory rate
Dyspnea >35 breaths/min
Dyspnea >45 breaths/min
Blood gas values
O2 saturation <90%
O2 saturation <86%
Other symptoms
Mild to moderate claudication
Onset of pallor
Facial expression of distress
Lightheadedness or mild dizziness
Postactivity fatigue >1 hr
Slow recovery from activity
Severe, persistent claudication
Cyanosis, severe pallor, or cold sweat
Facial expression of severe distress
Moderate to severe dizziness, syncope
Nausea, vomiting
Increasing mental confusion
Onset of ataxia, incoordination
Additional considerations







Fever >100°F
Aortic stenosis
Recent mental confusion
Abnormal electrolytes (potassium)
Known left main coronary artery disease
Idiopathic hypertrophic subaortic stenosis
Compensated heart failure

Any acute illness
Digoxin toxicity
Overt congestive heart failure
Untreated second or third degree heart block
Acute pericarditis
<4 to 6 weeks after myocardial infarction
<2 days after pulmonary embolism
Acute thrombophlebitis
Acute hypoglycemia
bpm, Beats per minute; DBP, diastolic blood pressure; ECG, electrocardiogram; HR, heart rate; SBP, systolic blood pressure.
Modified from Hillegass E (ed), Essentials of Cardiopulmonary Physical Therapy, 3rd ed. St. Louis: Elsevier Saunders, 2011, pp. 307, 564, 586.

22
Section I  Building Baseline Knowledge
maximal HR also signals that an older person's HR reserve, the
difference between the rate for any given level of activity and
the maximal attainable HR, is limited as well. For older patients
involved in rehabilitation programs, the difference between
resting and maximal HR is narrowed. One method of estimat­
ing maximal (max) attainable HR is the following5:
For healthy individuals, the recommended target HR for
aerobic conditioning exercise is between 60% and 80% of
maximal attainable HR. For many older adults, especially
those who are habitually inactive, resting HR may be close to
the recommended range for exercise exertion.76 Consider an
80-year-old individual with a resting HR of 72 beats per min­
ute. His maximal attainable HR is approximately 140 beats
per minute (220 − 80 years). A target HR for an aerobic train­
ing level of exertion of 60% of maximal HR would be 84 beats
per minute. His resting HR is within 12 beats of the HR for
aerobic training. Functionally, this means that an activity as
routine as rising from a chair or walking a short distance
on a level surface may represent physical work of a level of
exertion equated with moderate- to high-intensity exercise.
Because of the reduction in maximal attainable HR with age,
older adults may be working close to their VO2max range even
in usual activities of daily living.76,77
Because HR essentially signals the work of the heart, with
each beat representing ventricular contraction, increased HR
relates closely to increased heart work and increased oxygen con­
sumption by the myocardium.75 Given that afterload on the heart
increases with age, the overall work of the heart for each beat is
likely greater as well.21,38,39,40 A more representative way to esti­
mate the work of the heart during activity for older adults is the
rate pressure product (RPP),78–80 using HR and SBP as follows:
The linear relationship between VO2max and HR for
younger adults actually levels off for older adults.81 Because
of this, HR alone cannot accurately reflect the physiological
work that the older patient experiences; the RPP provides a
clearer impression of relative work.80 For older individuals
with HR reserve limited by age, adjusting activity to keep the
rise in HR within the lower end of the HR reserve is wise,
especially for those with known coronary artery compromise.
Blood Pressure as a Warning Sign
An older person's blood pressure (BP) must also be consid­
ered. Hypertension, particularly increased SBP, is common
in older adults. SBP also provides a relative indication of the
level of afterload on the heart.40,82,83 Resting BP can be used to
indicate whether an older person can safely tolerate increased
physiological work. Persons with resting BPs of more than
180/95 mm Hg may have difficulty with increased activity.
A conservative estimate of the safe range of exercise sug­
gests that exercise should be stopped if and when BP exceeds
220/110 mm Hg, although some consider 220 mm Hg too
conservative a limit for older adults.75 SBP should rise with
increasing activity or exercise.84
The older adult with limited HR reserve must increase SV
to achieve the required CO.21,39,53 SBP rises as SV increases
and blood volume in the peripheral vasculature rises.40 If
SBP fails to rise or actually decreases during activity, this is
a significant concern.75 The drop or lack of change in SBP
indicates that the heart is an ineffective pump, unable to con­
tract and force a reasonable volume of blood out of the left
ventricle. Continuing exercise or activity in the presence of a
dropping SBP returns more blood to a heart that is incapable
of pumping it back out to the body. Elevated diastolic blood
pressure (DBP) suggests that the left ventricle is maintaining
a higher pressure during the filling period.39,40,69 Early dia­
stolic filling during preload will be compromised,40,49 and the
heart will be unable to capitalize on the Frank-Starling mech­
anism to enhance the force of ventricular contraction.21,53
Respiratory Warning Signs
Dyspnea, or shortness of breath, is an important warning sign as
well. Age-related changes in the pulmonary system increase the
work of breathing, and breathing becomes less efficient as work
increases.72 Because an older person is prone to shortness of
breath, recovering from shortness of breath during exercise may
be difficult. Breathing more deeply requires a disproportion­
ately greater amount of respiratory muscle work, which further
increases the cost of ventilation.73,74 The use of supplemental oxy­
gen by nasal cannula for the postoperative or medically ill older
adult who is beginning rehabilitation may be quite beneficial.
Oxygen supplementation may prevent or minimize short­
ness of breath, enabling an older person to tolerate increased
activity better and to participate in rehabilitation more fully.
During this oxygen-assisted time, any conditioning exercise
to improve muscular performance (especially if combined
with nutritional support) delivers blood to the working tis­
sues and improves tissue oxygenation, ultimately aiding pul­
monary function. Improved muscular conditioning and
cardiovascular function may prevent or delay onset of lactic
acidemia and the resultant increased desire to breathe that
would trigger shortness of breath.72,85
Optimizing Cardiopulmonary Performance
For most older adults, conditioning or training is an effective
way to improve function, although some may need a longer
training period than younger adults to accomplish their desired
level of physical performance.86–90 Physical conditioning, in situ­
ations of acute and chronic illness, enables the older person to
do more work and better accomplish desired tasks or activities.
Older adults, including those who are quite debilitated,
experience improvement in physical performance as a result
of conditioning exercises88 (Figure  2-5). For some, signifi­
cant gains are made as work capacity increases from an initial
state below the threshold necessary for function, such that an
older person appears to make greater gains than a younger
­individual in similar circumstances.91,92 In many cases the
­cardiopulmonary system efficiency gained through condi­
tioning means the difference between independence and
=
−
Max HR
220
age
=
×
RPP
HR
SBP

Chapter 2  Aging and Activity Tolerance: Implications for Orthotic and Prosthetic Rehabilitation
23
dependency, functional recovery and minimal improvement,
life without extraordinary means and life support, and, for
some older individuals, life and death.
The physiological mechanisms for achieving the condi­
tioned responses of older adults may vary slightly from those of
younger individuals. With increasing activity or exercise in the
submaximal range, older adults demonstrate greater increases
in SV and less rise in HR than do young adults.21,40,49,53,75 This
increase in SV is accomplished with an increased EDV, usu­
ally without change in the ESV.21,40,49 Increasing the EDV
enhances the force of ventricular contraction by the Frank-
Starling mechanism, which, in turn, increases CO despite the
age-related impairment of the cardioacceleratory responses,
which limits the rise in HR.21,39,40,49,53 An increased preload,
which improves CO, is the usual outcome of training at any
age because improved conditioning of the peripheral muscu­
lature prevents distal pooling of blood and increased resting
tension of the muscles assists blood return.75
Preparation for Activity and Exercise
Simple lower extremity exercise as a warmup before any func­
tional activity or training session enhances the preload of the
heart. Any gentle, repetitive, active lower extremity motions
(e.g., ankle “pumps” in dorsiflexion/plantar flexion, knee
flexion/extension, or cycling movements of the legs) before
transfer or ambulation activities, before upper trunk and upper
extremity activities, or as part of the warmup portion of an aer­
obic or strength training exercise effectively improves the EDV.
This increased EDV compensates in part for age-related preload
problems, which might otherwise compromise work capacity.
Additionally, the muscular work of preliminary lower
extremity exercise initiates the electrolyte and hormonal
changes that promote the metabolic changes and vasodilation
in peripheral tissues necessary to support aerobic metabolism
for meeting energy demands of the task.75,88 Peripheral oxy­
gen exchange improves as much as 16% with regular exercise
training.21 The peripheral vasodilation associated with exer­
cise helps to check the rise in afterload on the heart and also
minimizes the development of lactic acidemia and the result­
ing drive to breathe more rapidly.93
As submaximal levels of exercise increase toward maxi­
mal exercise, SV continues to increase, maintaining CO.21,49,53
When cardiopulmonary disease is present in addition to
aging, however, this continued increase in SV is likely to be
blunted.39,75 Under these circumstances, the reduced sensi­
tivity of the heart to sympathetic stimulation limits the force
of contraction of the ventricle so that the ejection fraction
decreases and the ESV rises slightly.40
Monitoring the Cardiorespiratory Response
to Exercise
Consistent monitoring of the cardiopulmonary response is an
essential component of rehabilitation interventions aimed at
optimizing endurance or fitness of older frail or deconditioned
individuals.76,94 The positive effects of training only occur when
the older person is appropriately challenged by the exercise
or activity. According to the principle of overload, functional
improvements occur only when the body is asked to do more
than the customary workload for that individual.5 For an indi­
vidual who has been on prolonged bed rest and is quite decon­
ditioned, simple lower extremity exercises while sitting upright
may be as challenging as training for a marathon in a healthy
young adult. The level of physiological exertion is relative to
the individual's customary work. Providing the physiological
overload necessary to produce improvements in performance,
while avoiding a decline in performance because of exercise-
induced fatigue or exhaustion, requires that the therapist moni­
tor an individual's level of exertion.
Heart Rate and Blood Pressure
Maximum oxygen consumption (VO2max) is the most accu­
rate and sensitive measure of the individual workload, but
the special equipment and technology necessary to determine
VO2max are not typically available in routine clinical practice.75,76
Although the linear relationship between HR and VO2max pla­
teaus so that HR becomes an inaccurate reflection of the work­
load for older adults, HR does partially indicate the work of the
heart.75,81 For a rapid clinical impression of the physiological
burden of an activity or exercise, HR is helpful as long as the cli­
nician recognizes its limitations when using the measure with
elders. Preexercise or activity BP provides some indication of
Time
Low
High
Illness
Recovery
Healthy
Sedentary
Frail
Threshold for
functional limitation
Functional capacity
Pre-illness level of function
Recovery: with exercise
without exercise
A
B
C
FIGURE  2-5  Comparison of the impact of illness or prolonged
inactivity, or both, on functional status and of exercise on recovery
of premorbid functional levels of healthy, sedentary, and frail older
adults. Each individual's functional reserve is represented by the
distance between the threshold for functional limitation and their
functional capacity. A, Healthy older adults have the most functional
reserve and may recover preillness functional capacity without con­
ditioning exercise but often show improvement above baseline with
exercise. B, Sedentary older adults may not resume preillness func­
tional capacity without the benefit of conditioning exercise. C, Frail
older adults have the least functional reserve, often fall below thresh­
old for function when illness occurs, and tend to remain below this
threshold without conditioning exercise. However, even frail older
adults can regain functional status with conditioning exercise.

24
Section I  Building Baseline Knowledge
likely afterload against which the heart will be ­working.40,75,84
Continuing to monitor BP during the activity helps the clini­
cian to recognize if the exercising cardiovascular system can
meet the requirements of an increasing workload.75 Calculation
of the RPP (HR × BP) may be a more accurate ­estimate of
­cardiac workload for older adults.79,80,84
Perceived Exertion
Ratings of perceived exertion are also effective indicators of
the level of physiological exertion experienced by patients
who are exercising or involved in a strenuous physical
activity75,95,96 (Table 2-4).
These scales ask individuals to assess subjectively how
much effort they are expending during an exercise session or
activity, with higher ratings indicating greater effort. Similar
scales have been developed to assess breathlessness, fatigue,
and discomfort or pain during exercise (Table  2-5). In the
clinical use of these ratings of perceived exertion, many older
persons using ratings of perceived exertion tend to overestimate
their true physiological stress, as indicated by their HR during
exercise sessions.75,95 Clinicians who appropriately recommend
exercise for older adults relying on perceived exertion to limit
the activity safely may find this phenomenon comforting.
Exercise Testing Protocols
Standard exercise testing protocols are appropriate for asse­
ssment of the status of conditioning of the ­cardiovascular
­system and exercise tolerance of older adults.76,97 The “gold
standard” treadmill test, a cycle ergometer, or a step test can
be used in assessing cardiovascular performance of the older
person, unless the specific clinical setting or associated mus­
culoskeletal dysfunction (e.g., balance problems, arthritic
joints, or lower extremity muscle weakness) precludes this
type of testing.76 Alternatives for individuals who can walk
distances include the One-Mile Walk Test and the Six-Minute
Walk Test.98–100 A brief step test performed while sitting in a
chair has been developed for individuals who cannot other­
wise be safely tested on a treadmill, with an ergometer, or by
distance walked.75,101
Careful monitoring of HR and BP before the sitting step
test, at predetermined points during testing, at the completion
of a brief bout of exercise, and a short while into recovery from
the exercise bout provides a comprehensive picture of cardio­
vascular function of any given older patient. This information
often proves important in clinical decision making and pro­
gram planning. Similarly, careful monitoring of HR and BP
before, during, and after a bout of exercise during rehabilita­
tion allows the clinician to compare the pattern of responses
with the expected pattern for conditioned adults.102 Normal
exercise-induced cardiovascular responses include a slow rate
of rise of HR, a rise in SBP, and minimal (if any) rise in DBP
during the exercise bout. For the conditioned older adult, HR
and SBP should return toward preexercise values during the
immediate postexercise recovery period, on the order of 50%
TABLE 2-4  Borg Scales:Ratings of Perceived Exertion
Linear Scale
Ratio Scale
Value
Description
Value
Description
6
No exertion
0
No effort at all
7-8
Extremely light effort
1
Very little (very weak) effort
9-10
Very light effort
2
Light (weak) effort
11-12
Light effort
3
Moderate effort
13-14
Somewhat hard effort
4
Somewhat strong effort
15-16
Heavy or hard
5-6
Strong effort
17-18
Very hard effort
7-8
Very strong effort
19
Extremely hard effort
9
Extremely strong effort
20
Maximum exertion
10
Maximal exertion
Modified from Borg G, Ottoson D. The Perception of Exertion in Physical Work. London: Macmillan, 1986.
TABLE 2-5  Ratio Scales of Perceived Breathlessness, Fatigue, or Discomfort During Exercise
Value
Breathlessness/Dyspnea
Fatigue
Discomfort or Pain
0
No breathlessness at all
No fatigue at all
No pain or discomfort
1
Very light breathlessness
Very light fatigue
Very little (weak) pain
2
Light breathlessness
Light fatigue
Little (weak) discomfort
3
Moderate breathlessness
Moderate fatigue
Moderate discomfort
4
Somewhat hard to breathe
Somewhat hard
Somewhat strong discomfort
5-
Heavy breathing
Heavy work/fatigue
Strong discomfort or pain
7-8
Very heavy breathing
Very heavy fatigue
Very heavy discomfort
9
Very, very breathless
Very, very fatigued
Very, very hard discomfort
10
Maximum breathlessness
Maximally fatigued
Maximal discomfort or pain
Modified from Dean E. Mobilization and exercise. In Frownfelter D, Dean E (eds), Principles and Practice of Cardiopulmonary Physical
Therapy, 3 rd ed. St. Louis: Mosby, 1996, p. 282.

Chapter 2  Aging and Activity Tolerance: Implications for Orthotic and Prosthetic Rehabilitation
25
of the changes during exercise. The pattern of change in the
RPP for the exercise bout and recovery period may be an even
more descriptive measure of the cardiovascular response.
Expecting individuals who are significantly deconditioned,
can barely tolerate sitting for 30 minutes, are short of breath after
10 repetitions of simple lower extremity exercises while sitting,
or are fatigued after 5 minutes of a sitting step test to be fully
able to participate in gait and balance training is unreasonable.
How can older individuals who are working at 90% or more of
their maximum target HR be truly concerned with much more
than delivering oxygen to the working tissues? Deconditioned
individuals who are working at a high intensity in simple, well-
known tasks have seriously restricted energy reserves; they are
likely to have difficulty with focus and attention, processing,
and the therapist's directions and supporting muscle activity—
all necessary components for motor learning in performing a
new skill such as gait training with a prosthetic device. Under
these circumstances emphasis must first be placed on improv­
ing cardiovascular conditioning, to improve energy reserves so
that subsequent functional training with an orthosis or pros­
thesis has greater likelihood of a successful outcome.
Physical Performance Training
The same principles of training that are used with young adult
athletes can be adapted and applied to frail or deconditioned
older adults who are recovering from amputation in pros­
thetic rehabilitation or a neuromuscular or musculoskeletal
event that necessitates use of an orthosis. The primary goals
of conditioning for frail individuals are (1) to develop enough
aerobic capacity to do work and (2) to ensure efficient mus­
cle function to produce work.75,76,103 These concepts can guide
any single rehabilitation session, as well as the progression of
the rehabilitation program over time. An understanding of
exercise for improving fitness and of the few physiological
age-related changes in cardiopulmonary function provide a
foundation for exercise prescription, which then is individu­
alized on the basis of current exercise tolerance of a specific
older patient. This strategy can likely optimize the perfor­
mance and recovery of older adults in rehabilitation.
An effective strategy to improve cardiopulmonary
response to exercise and activity for older patients who are
deconditioned by bed rest, acute illness, or sedentary lifestyle
begins with a warmup of continuous alternating movements
using large muscle groups, particularly of the lower extrem­
ities. The goal of such activity is facilitation of the preload
and SV; any increase in SV realized through this training regi­
men helps an older patient maximize cardiovascular function
despite age-associated limitations in HR, cardioacceleratory
responses, and baroreceptor sensitivity.
For healthy young adults, the recommended regimen for
aerobic conditioning and endurance training involves at least
three sessions per week of 30 to 60 minutes’ duration in activi­
ties that use large muscles (running, cycling, swimming, brisk
walking) and keep HR in a target range between 60% and
80% of the individual's maximal attainable HR.104 This may
be unreasonable for an older adult who is recovering from
an acute illness, habitually sedentary, or coping with age- or
pathology-related impairments of cardiac or pulmonary func­
tion. Evidence suggests that, for older adults who are decon­
ditioned, slower but significant improvement in functional
capacity can occur at exercise intensities as low as 40% of
maximal HR.87,105,106 Although high-frequency, ­high-intensity
exercise can maximize increase in work capacity (VO2max),
high-intensity exercise performed less frequently and low-
intensity exercise performed more frequently can also yield
positive endurance training effects.107 Evidence is also grow­
ing of improvement in oxygen extraction and muscle function
when older adults are involved in regular endurance training.106
In addition to aerobic conditioning, the rehabilitation pro­
gram might include exercises that focus on flexibility. One
goal of stretching and flexibility exercise for older adults is
to preserve or restore any limited joint mobility that would
otherwise compromise essential functions.108 As flexibility of
the trunk and thorax improves, a more effective alignment of
the diaphragm and improved elastic recoil of the chest wall
will have a positive impact on VC and inspiratory reserve
volume and minimize RV, reducing the work of breathing
and improving ventilation. Availability of essential range of
motion is especially important for energy-efficient gait with
lower limb orthoses or prostheses. Contracture of the hip,
knee, or ankle has an impact on the alignment of orthotic and
prosthetic components and often leads to greater sway and
smaller stride length during gait, significantly increasing the
energy cost or workload of walking.
Muscle strengthening can begin as soon as the aerobic
conditioning appears adequate to oxygenate the peripheral
muscular tissue sufficiently. Assessment of the adequacy of
peripheral oxygenation might include monitoring the color­
ing of the distal extremities before and during exercise and
noting whether cramping or claudication occurs during
exercise. One of the most sensitive indicators of appropri­
ate intensity and duration of exercise is whether the activity
can be increased without a marked rise in respiratory rate or
onset of shortness of breath; a potent stimulus for frequency
of breathing is the pH of the exercising tissues, with decreases
as lactic acid builds up during anaerobic exercise.
Two factors should be considered when including strength­
ening exercises in a rehabilitation program.94 First, is there ade­
quate muscle strength for consistent and safe performance of
the motor tasks needed for functional independence (including
the use of assistive devices)? Second, is the muscle mass large
enough to support a VO2max that allows activities of daily living
to represent a light to modest work intensity level? For many
older people who have lost muscle mass (whether as a result of
disuse and sedentary lifestyle or because of recent health prob­
lems that limit activity), development of more muscle mass
increases lean body mass and improves the basal metabolic rate,
improving overall health, fitness, and functional status.109,110
ENERGY COST OF WALKING
The human body is designed to be energy efficient during
upright bipedal gait. Muscles of the trunk and extremities are
activated by the CNS in a precise rhythmic cycle to move the

26
Section I  Building Baseline Knowledge
body ­forward while maintaining dynamic stability, adapting
stride length and walking speed to the constraints and demands
of the task, the force of gravity, and the characteristics of the envi­
ronment in which walking is occurring.111,112 The advancing foot
is lifted just enough to clear the surface in swing, and muscle
activity at the stance-side hip and lower torso keeps the pelvis
fairly level and the trunk erect, minimizing vertical displacement
of the body's center of mass.113 Normal arthrokinematic and
osteokinematic relationships between body segments ensure a
narrow base of support in quiet stance and relaxed walking, and
reciprocal arm swing counterbalances the dynamic pendular
motion of the lower extremities, ensuring that the center of mass
progresses forward with minimal mediolateral sway.113–116 Much
of the energy cost of walking is related to the muscular work per­
formed to keep the center of mass moving forward with a mini­
mum of vertical and mediolateral displacement.117
Self-Selected Walking Speed
Because self-selected walking speed emerges from the inter­
action of the cardiovascular, pulmonary, musculoskeletal,
and neurological systems, it reflects the overall health and
functional status of an individual.118 Walking speed is recog­
nized as a vital sign that not only captures current function,
but also can be used to predict risk of functional decline,
adverse health events and morbidity, length of stay and dis­
charge location after hospitalization, and mortality.119–128
Although self-selected walking speed tends to decrease with
aging, multiple studies have demonstrated that even into the
ninth and tenth decades of life, healthy older adults are able
to walk at speeds at or greater than 1 m/sec (Table 2-6).129–131
Values for typical walking speed are also becoming available
for community living older adults with impaired mobility
and physical frailty.132,133 There is also evidence that the abil­
ity to increase walking speed is an indicator of functional
reserve.129,133,134
Walking speed can be quickly and reliably measured using
a stop watch and either a 20- or 6-m walkway (Figure 2-6).
The indivudal is instructed to walk over the entire distance of
the walkway but is timed only while walking the middle two
thirds (10 or 4 m) of the distance so that steady-state speed is
TABLE 2-6  Typical Self-Selected and Fast Walking Speeds for Community-Living Healthy and Mobility-Impaired
Older Adults, Reported as Mean SD (m/sec)
Researcher:
Chui et al129
Bohannon131
Steffen et al130
Lusardi et al133
Population
Healthy
Healthy
Healthy
Mobility Impaired
Gender
Age Group
SSWS
FWS
SSWS
FWS
SSWS
FWS
SSWS
FWS
Women
60-69
—
—
1.30 (0.21)
1.77 (0.25)
1.44 (0.25)
1.87 (0.30)
1.24 (0.12)
1.81 (0.17)
70-79
1.34 (0.26)
1.69 (0.32)
1.27 (0.21)
1.79 (0.28)
1.33 (0.22)
1.71 (0.26)
1.25 (0.18)
1.80 (0.26)
80-89
1.05 (0.12)
1.44 (0.17)
—
—
1.15 (0.21)
1.59 (0.28)
0.80 (0.16)*
1.20 (0.29)
90-99
0.80 (0.17)
1.05 (0.22)
—
—
—
—
0.71 (0.23)†
1.05 (0.32)†
Men


60-69
—
—
1.36 (0.21)
1.93 (0.36)
1.59 (0.24)
2.05 (0.31)
—
—
70-79
1.55 (0.58)
2.19 (0.78)
1.33 (0.20)
2.08 (0.36)
1.38 (0.23)
1.83 (0.44)
1.25 (0.23)
1.94 (0.26)
80-89
1.30 (0.15)
1.75 (0.21)
—
—
1.21 (0.18)
1.65 (0.24)
0.88 (0.24)*
1.29 (0.38)*
90-99
1.10 (0.38)
1.55 (0.66)
—
—
—
—
0.72 (0.14)†
1.27 (0.13)†
*29.4% of older adults in sample routinely used rolling walker, standard walker, or cane while walking.
†58.8% of older adults in sample routinely used rolling walker, standard walker, or cane while walking.
FWS, Fast walking speek; SSWS, self-selected walking speed.
Acceleration
Zone
Timed Walk
Deceleration
Zone
1 meter
4 meters
1 meter
5 meters
10 meters
5 meters
FIGURE 2-6  Strategy for assessing self selected or fast walking speed timing either the central 10-m
distance (10- m walk) or central 4-m distance (4-m walk) allowing for acceleration and deceleration
at either end, so that steady state speed is better approximated.

Chapter 2  Aging and Activity Tolerance: Implications for Orthotic and Prosthetic Rehabilitation
27
more likely, and the impact of acceleration (at the start) and
deceleration (at the end) are minimized. Reliability is strong
at either distance for persons with amputation, stroke, and
spinal cord injury, as well as physical frailty and other neu­
rological pathologies.135–138 Minimal detectable differences
(MDD) have been consistently reported as between 0.08 m/sec
to 0.1 m/sec for community-living persons, those with cog­
nitive impairment, and those with hip fractures.129,139,140
Minimal clinically important difference for walking speed
following stroke is reported to be 0.16 m/sec.141 Walking
speed has been successfully used to evaluate the outcome
of interventions for persons with cognitive impairments as
well as those with hip fractures.129,139,140
Any musculoskeletal or neuromuscular pathology that
interferes with the alignment of body segments, the carefully
controlled sequential activation of muscles, or the effective­
ness of muscle contraction increases the energy cost of walk­
ing. As vertical displacement and mediolateral sway increase
and gait deviations occur, muscles must work harder to keep
the center of mass moving forward despite extraneous dis­
placing moments. As muscle work increases, the cardiopul­
monary system responds to this physiological demand with
increased HR, SV, and respiratory rate. Any orthosis or pros­
thesis that adds mass to or alters movement of the lower
extremity potentially increases the work of walking. However,
in individuals with amputation or neuromuscular dysfunc­
tion, walking with an appropriate prosthesis or orthosis may
actually require less energy than walking without it.117,142,143
Measuring Energy Costs of Walking
Measurement of physiological energy expenditure by direct cal­
orimetry is not realistic in all but the most sophisticated research
laboratory settings. Instead, several indirect indicators have
been found to be valid and reliable estimates of the energy cost
and the efficiency of gait in research and clinical applications.
These include calculation of oxygen consumption (VO2max) and
oxygen cost while walking, monitoring blood lactate levels,
calculating the physiological cost index (PCI) of walking, and
monitoring heart and respiratory rates during activity.
Oxygen Rate and Oxygen Cost
The most precise indirect measurements of energy and gait
efficiency use special equipment (e.g., a portable spirome­
ter or a Douglas bag) to monitor ventilatory volumes and to
measure how much oxygen is taken in and carbon dioxide
exhaled during physical activity. This type of testing is usually
done while the subject or patient walks, runs on a treadmill
or track, or cycles on a stationary bicycle. The rate of oxy­
gen consumption (O2 rate), measured as volume of oxygen
consumed per unit of body weight in 1 minute (mL/kg/min),
provides an index of intensity of physical work at any given
time.115,144 VO2max is the highest rate of oxygen uptake possi­
ble and is determined by progressing the exercise test to the
point of voluntary exhaustion, when the age-adjusted maxi­
mum attainable HR is approached or reached.145,146
If oxygen consumption during gait is low, an individual is
likely to be able to walk long distances. If it is high, ­however,
the distance of functional gait is likely to be limited. The oxy­
gen cost of walking is determined by dividing the rate of oxy­
gen consumption by the speed of walking. Oxygen cost is a
precise indicator of efficiency of gait, the amount of energy
expended to walk over a standard distance (mL/kg/m).115
Most of what researchers currently understand about energy
expenditure when using a prosthesis or orthosis is based on
studies that have measured oxygen rate and oxygen cost of
walking.
Serum Lactate
The energy efficiency of walking is also assessed by evalua­
tion of serum carbon dioxide and lactate levels as indicators
of anaerobic energy production. The energy (adenosine tri­
phosphate [ATP]) required for muscle contraction during
gait can be derived from a combination of aerobic oxidative
and anaerobic glycolytic pathways.147 The aerobic oxidative
pathway, which depends on oxygen delivery to active muscle
cells, is the most efficient source of energy, producing almost
19 times as much ATP as the anaerobic pathway. In healthy,
fit individuals, this aerobic pathway is more than able to meet
energy requirements of relaxed walking. If energy demands of
an exercise or activity are met by aerobic oxidation, the activ­
ity can be sustained for long periods with relatively low lev­
els of fatigue. As activity becomes strenuous (i.e., as walking
speed or surface incline increases) and the need for energy
begins to exceed the availability of oxygen for aerobic oxida­
tion, additional energy is accessed through anaerobic metab­
olism.148 This transition to anaerobic metabolism is reported
to begin at work levels of 55% of VO2max in healthy, untrained
individuals but may begin at 80% of VO2max in highly trained
athletes.149
When the ability to deliver oxygen is compromised by the
physical deconditioning of a sedentary lifestyle or by cardiac,
pulmonary, or musculoskeletal pathology, anaerobic glycol­
ysis becomes a primary source of energy at lower levels of
work.150 Whenever the anaerobic pathway is the major source
of energy, blood levels of lactate and carbon dioxide rise, low­
ering blood pH and increasing the respiratory exchange ratio
(CO2 production/O2 consumption).151 Under these condi­
tions, the ability to sustain activity is limited, with an earlier
onset of fatigue as workload increases. Serum lactate levels
are most often used in studies of assisted ambulation using
hybrid orthotic/functional electrical stimulation systems for
those with spinal cord injury.
Heart Rate and Physiological Cost Index
High correlations between HR and oxygen consumption
­during gait have been reported for children and for healthy
young adults at a variety of walking speeds.152,153 Although
this suggests that HR monitoring may be a reliable substi­
tute for oxygen consumption, it should be used with caution
in older adults because of the age-related changes in cardio­
pulmonary function discussed earlier in this chapter. This
is especially true for older adults with heart disease who
are being managed with medications that further blunt HR
response.154,155 The RPP or the PCI may be more ­appropriate

28
Section I  Building Baseline Knowledge
indicators of the energy cost of walking in these circum­
stances. The PCI is calculated as follows156:
Measured in beats per meter, the PCI reflects the effort of
walking; low values suggest energy-efficient gait. The PCI was
originally used to assess gait restrictions in adults with rheu­
matoid arthritis and similar inflammatory joint disease.156
For children between 3 and 12 years of age, the mean PCI at
self-selected or preferred walking speed has been reported to
be between 0.38 and 0.40 beats per meter.157 Typical PCI val­
ues for adolescents and young adults at usual walking speeds
ranged from 0.3 to 0.4 beats per meter.158 In a study of healthy
adults older than age 65 years, the mean PCI value when
walking on a flat 10-m track was 0.43 (SD = 0.13) beats per
meter; when calculated while walking on a treadmill, mean
PCI increased to 0.60 (SD = 0.26) beats per meter.159
The PCI has been used to assess the effect of different
assistive devices on the effort of walking,160 evaluate the short-
and long-term impact on neuromuscular stimulation on the
ability to walk and run in older adults and in children with
hemiplegia, assess outcomes of orthopedic surgery in chil­
dren with cerebral palsy, and evaluate the efficacy of recip­
rocal gait orthosis/functional electrical stimulation systems
for individuals with spinal cord injury.161–169 High correla­
tion among the PCI, percent maximum HR, and oxygen rate
(r = 0.91, P > .005) in able-bodied children and children with
transtibial amputation supports its validity as an indicator of
energy cost for children.170 A similar study of energy cost of
walking in young adults using a microprocessor-controlled
transfemoral prosthesis suggests that PCI is comparable with
oxygen uptake as an indicator of the energy cost of walking.171
The PCI has also been used to compare energy cost of walk­
ing in different types of transfemoral prosthetic sockets and
assess efficacy of a stance control knee orthosis.172,173
Studies of variability in PCI values on repeated measures have
raised questions about its accuracy and sensitivity to change in
energy cost of gait, as compared with monitoring of oxygen
consumption and oxygen cost.174–176 Although the relationship
between PCI and the “gold standards” of oxygen consumption
and oxygen cost may not be strong enough for researchers, it
remains an important tool for clinicians who lack the resources
necessary to directly monitor oxygen consumption and cost
yet want to estimate the energy cost of walking and assess the
impact of orthotic or prosthetic rehabilitation over time.
Energy Expenditure at Self-Selected Walking Speeds
The energy requirements of walking vary with age and walking
speed.176–182 Oxygen consumption is highest in childhood and
decreases to approximately 12 mL/kg/min in healthy adults and
elders.177 When oxygen consumption during walking is expressed
as a percent of VO2max, a slightly different picture emerges. For a
healthy, untrained young adult, oxygen consumption at a com­
fortable walking speed may be 32% of VO2max, whereas for an
older adult walking at a similar speed, oxygen consumption may
be as much as 48% of VO2max.113,183 For functional gait, if walking
is to cover long distances or is to be sustained over prolonged
periods of time, oxygen consumption must be less than 50% of
that individual's VO2max so that aerobic oxidation will be used as
the primary source of energy.5 At comfortable walking speeds,
older adults are working nearer the threshold for transition to
anaerobic metabolism than are younger adults. If some form of
gait dysfunction is superimposed, increasing the energy cost of
gait, the work of walking will transition to anaerobic glycolysis
unless a cardiovascular conditioning program is included in the
rehabilitation program.184
For individuals without neuromuscular or musculoskeletal
impairment, the relationship between the energy cost of walk­
ing and walking speed is nearly linear185 (Figure 2-7). Gait is
most efficient, as indicated by oxygen cost (O2 rate/velocity), at
an individual's self-selected or customary walking speed; energy
requirements increase whenever walking speed is much slower
or much faster.185–188 The customary walking speed of most indi­
viduals with neuromuscular or musculoskeletal impairments is
often much slower, a strategy that minimizes the rate of energy
used during walking. As a result of slower speed, however, it
takes longer to cover any given distance. Any impairment that
reduces walking speed leads to increased oxygen cost, even if
oxygen consumption remains close to normal.189–194
The weight and design of the prosthesis or orthosis are also
determinants of energy cost of gait. The impact of added mass on
the energy cost of gait depends on where the load is placed: Extra
weight loaded on the trunk (e.g., a heavy backpack) changes oxy­
gen rate during walking less than would a smaller load placed
around the ankle.195 This highlights the importance of minimiz­
ing weight of lower extremity orthoses and prostheses to keep the
energy cost of walking within an individual's aerobic capacity.196
Work of Walking with an Orthosis
When discussing the energy cost of walking with an orthosis, it
is important to remember that, for those with significant neu­
romuscular or musculoskeletal impairment, the energy cost of
=
−
PCI
(HR walking
HR resting)/walking speed
25
20
15
10
5
Gait speed (m/min)
20
40
60
80
100
O2 Consumption (ml/kg-min)
Children
Teens
Adults
FIGURE 2-7  Relationship between walking speed and oxygen con­
sumption (O2 rate). The differences in O2 rate between children and
adults (20 to 80 years) are attributed, in part, to differences in body
composition. (From gait-velocity regression formulas reported by
R. L. Waters. Energy expenditure. In Perry J, Burnfield JM [eds],
Gait Analysis: Normal and Pathological Function. Thorofare, NJ:
Slack, 2010. pp. 483-518.)

Chapter 2  Aging and Activity Tolerance: Implications for Orthotic and Prosthetic Rehabilitation
29
walking without the orthosis is typically higher than walking
with an appropriate orthosis.197–199 One of the determinants of
energy cost when walking with a cast or an orthosis is the degree
of immobility that the orthosis imposes on the ankle, knee, and
hip and the associated change in walking speed.200 For individu­
als with restriction of knee motion because of a cast or orthosis,
the energy cost of gait can be reduced by placing a shoe lift on
the contralateral limb to improve swing limb clearance.201
For individuals with spinal cord injury, regardless of age,
the potential for functional ambulation appears to be deter­
mined by four conditions: the ability to use a reciprocal gait
pattern, the adequacy of trunk stability, at least fair hip flexor
strength bilaterally, and fair quadriceps strength of at least
one limb.202,203 This corresponds to an ambulatory motor
index (AMI) score of 18 of 30 possible points, or 60% of
“good” lower extremity strength.179 In this instance, gait may
be possible with bilateral ankle-foot orthoses (AFOs) or an
AFO and knee-ankle-foot orthosis combination. Those with
spinal cord injury at mid to low thoracic levels with AMI
scores of less than 60% often require bilateral ­knee-ankle-foot
orthoses, with Lofstrand or axillary crutches in a swing-
through gait pattern to ambulate. Waters117 reports a near
linear positive relationship between AMI scores and gait
velocity, as well as a somewhat curvilinear inverse relation­
ship between AMI score and oxygen rate (% above normal)
and oxygen cost. For persons with spinal cord injury who
have the potential for functional ambulation, continued car­
diovascular conditioning after discharge from rehabilita­
tion improves the efficiency of walking, as reflected in lower
oxygen cost and improvement in walking speed.203–205 The
development of reciprocal gait orthoses and “parawalkers,”
at times augmented by functional electrical stimulation, has
also made modified ambulation possible for those with injury
at mid and upper thoracic levels.206–214 The high energy cost of
the intense upper extremity work using crutches to propel the
body forward during swing and maintain upright position in
stance, however, restricts functional ambulation as a primary
means of mobility.
The movement dysfunction associated with stroke and
other neuromuscular impairments tends to reduce walking
speed, with the degree of slowing determined by the sever­
ity of neuromuscular impairment.190,198,215 As abnormal move­
ment patterns and impaired postural responses ­compromise
the cyclic and dynamic flow of walking, the higher levels of
muscle activity that are required to remain upright and to
move forward increase the energy cost of gait.216,217 Reduction
of walking speed is a functional strategy to keep energy expen­
diture within physiological limits. Oxygen rate (consump­
tion) of persons with stroke who walk at a reduced walking
speed is close to that of older adults who walk at their cus­
tomary walking speed; however, oxygen cost is significantly
higher.117,190,218 When compared with unimpaired individuals
who walk at similar speeds, persons with hemiplegia wear­
ing an AFO use 52% more energy; when they walk without
an orthosis, their energy cost can increase to as much as 65%
more than unimpaired gait.219
Work of Walking with a Prosthesis
The characteristics of gait and the energy cost of walking with
a prosthesis are related to the etiology and the level of ampu­
tation.220,221 The walking speed, stride length, and cadence of
persons with lower extremity amputation who walk with a
prosthesis are typically lower than those of individuals without
impairment, regardless of the cause of amputation,222 although
individuals with traumatic etiology tend to walk faster than
those with dysvascular etiology.223,224 Additionally, biome­
chanical and energy efficiency of prosthetic gait decreases as
amputation level increases. Therefore, preservation of the ana­
tomical knee joint appears to be especially important.222,225
A classic study by Waters and colleagues224 (Table 2-7)
demonstrated that, for young adults with traumatic trans­
tibial amputation, walking speed, oxygen rate, and oxy­
gen cost were quite close to normal values reported by
Perry.113 For those with traumatic transfemoral or dys­
vascular amputation, diminishing walking speeds kept
oxygen ­consumption close to that of normal adult gait; how­
ever, ­oxygen cost increased well beyond the normal value
of 0.15 mg/kg/m.200 Although walking speeds reported
20 years later by Torburn and colleagues223 are much higher
(most likely due to biomechanical advances in prosthetic
components in the time between the studies), the differ­
ence in performance between traumatic and dysvascular
groups was consistent. Other studies report oxygen costs
of prosthetic gait at between 16% and 28% above normal
TABLE 2-7  Walking Speed, Oxygen Consumption, and Oxygen Cost in Prosthetic Gait: Comparison of Etiology
and Level of Unilateral Amputation
Etiology and Level:
Traumatic
Dysvascular
Parameter
Transtibial
Transfemoral
Transtibial
Transfemoral
Waters et al, 1976224
Walking speed (m/min)
71
52
45
36
O2 rate (mL/kg/min)
12.4
10.3
9.4
10.8
O2 cost (mL/kg/m)
0.16
0.20
0.20
0.28
Torburn et al, 1995223
Walking speed (m/min)
82.3
—
61.7
—
O2 rate (mL/kg/min)
17.7
—
13.2
—
O2 cost (mL/kg/m)
0.22
—
0.21
—

30
Section I  Building Baseline Knowledge
for individuals with transtibial amputation and between
60% and 110% above normal for individuals with trans­
femoral amputation.226–230 Although the relationship
between walking speed and oxygen rate (consumption) in
prosthetic gait is linear, just as it is in unimpaired gait, the
slope is significantly steeper.231 The clinical implication of
this relationship is that the rate of energy consumption and
of cardiac work, at any ­walking speed, is higher for those
with amputation and that the threshold for transition from
aerobic to anaerobic metabolism is reached at lower walk­
ing speeds.232
Several explanations are possible for the differences in pros­
thetic gait performance after traumatic versus dysvascular
amputation. Because those with dysvascular amputation are
­typically older than those with traumatic amputation, differences
in performance may be the result of age-related changes and con­
current cardiovascular disease in the dysvascular group.226,233,234
For many older patients with dysvascular amputation, the energy
source for walking with a prosthesis may be anaerobic rather than
the more efficient aerobic metabolic pathways.223 A larger cardiac
and respiratory functional reserve capacity in younger persons with
traumatic transtibial amputation may permit them to meet the
increased metabolic demands of prosthetic use because proximal
muscle groups work for longer periods at higher intensities to
compensate for the loss of those at the ankle.223,231,235
Importantly, for most individuals with unilateral transtib­
ial and transfemoral amputation, regardless of age or etiology
of amputation, the energy cost of walking with a prosthe­
sis is less than that expended when walking without it using
crutches or a walker.224 For most persons with a new trans­
tibial amputation, the ability to ambulate before amputation
is the best predictor of tolerance of the increased energy cost
of walking with a prosthesis after surgery.233 For some older
individuals with transfemoral amputation and concurrent
cardiovascular or respiratory disease, and for those with bilat­
eral amputation at transfemoral/transtibial or bilateral trans­
femoral levels, wheelchair mobility may be preferred.236–239
Since the 1990s, significant efforts have been made to
reduce the energy cost of prosthetic gait by developing
dynamic response (energy storing) prosthetic feet and cadence-­
responsive and microprocessor-controlled prosthetic knee
units.240–254 The flexible keels of most dynamic response pros­
thetic feet are designed to mimic those of normal ankle mobil­
ity, such that mechanical energy stored by compression during
stance is released to enhance push-off in the terminal stance.218
However, the impact of different prosthetic foot designs on the
energy cost is not clear. For adults with transtibial amputation,
the FlexFoot functioned more like an anatomical ankle than did
four other dynamic response feet and the SACH foot, but little
difference in stride, velocity, or energy cost was noted.223,235,246
However, the materials and design of most dynamic response
feet may enable transtibial prosthetic users to jump, run, and
use a step-over step pattern in stair climbing; these activities
are difficult or not possible with a traditional SACH foot.224–251
Additionally, many individuals with transtibial amputation
wear their prosthesis for longer periods during the day and
report less fatigue in prolonged walking when using a prosthesis
with a dynamic response foot.233
SUMMARY
An understanding of normal cardiopulmonary function and
how it changes in aging, as a result of sedentary lifestyle or
pathological conditions, provides a necessary foundation
for rehabilitation professionals working with patients who
require an orthosis or prosthesis to walk. This chapter reviews
the anatomy and physiology of the cardiopulmonary system,
with attention to age-related changes, energy expenditure,
and principles of aerobic conditioning for older adults.
Optimal performance of the cardiopulmonary system
is influenced by three interrelated factors. First, the patient
must have sufficient flexibility and mobility of the trunk for
efficient and uncompromised ventilation. Second, adequate
mobility of the extremities and excursion of the joints must be
present for efficient performance of functional tasks. Third,
the individual must have enough muscle mass, strength, and
endurance to support the performance of the activity and
function of the heart. Immediate and ongoing interventions
that functionally enhance preload by returning blood to the
older heart and avoidance of conditions (e.g., isometric mus­
cle contraction and Valsalva maneuvers) that unnecessarily
increase afterload can result in marked improvement in phys­
ical performance of the older person. With these conditions,
as well as compensation for the beta-adrenergic receptor-
reduced sensitivity with a prolonged period of warmup exer­
cises, an older person is capable of physical performance that
is quite similar to that of younger counterparts and essential
for the process of recovery of function for the optimal out­
come of rehabilitation.
The energy cost and efficiency of gait are affected by aging,
deconditioning of a sedentary lifestyle, and neuromuscu­
lar and musculoskeletal impairments that alter motor con­
trol or the biomechanics of walking. Although an orthosis
that restricts joint motion increases the energy cost in unim­
paired individuals, the same orthosis leads to more efficient
gait in those with neuromuscular impairment. Determinants
of efficiency of prosthetic gait include the level and etiology
of the amputation. Reduction of walking speed when using
an orthosis or prosthesis helps to maintain oxygen consump­
tion at close to normal levels; however, this tends to compro­
mise overall efficiency of gait, as indicated by oxygen cost.
Attention to the principles of cardiovascular conditioning
including monitoring the response to exercise so that patients
are challenged appropriately optimizes the outcomes of
­rehabilitation programs.
REFERENCES
1. Des Jardins TR. Cardiopulmonary Anatomy and Physiology:
Essentials for Respiratory Care. 5th ed. Clifton Park, NY: Delmar
Publishers; 2008.
2. Phibbs B. The Human Heart: A Basic Guide to Heart Disease.
2nd ed. Philadelphia: Lippincott Williams & Wilkins; 2007.
3. Saltin B, Secher NH, Mitchel J, et  al., eds. Exercise and
Circulation in Health and Disease. Champaign, IL: Human
Kinetics; 2000.
4. Ekblom B, Astrand P, Saltin B, et al. Effect of training on
circulatory response to exercise. J Appl Physiol. 1968;
24(4):518–528.

Chapter 2  Aging and Activity Tolerance: Implications for Orthotic and Prosthetic Rehabilitation
31
5. Astrand P, Rodahl K, Dahl HA, et  al. Textbook of Work
Physiology: Physiological Bases of Exercise. 4th ed. Champaign,
IL: Human Kinetics; 2003.
6. Bolton E, Rajkumar C. The ageing cardiovascular system. Rev
Clin Gerontol. 2011;21(2):99–109.
7. Scalia GM, Khoo SK, O'Neill S. Age-related changes in heart
function by serial echocardiography in women aged 40-80
years. J Womens Health. 2010;19(9):1741–1745.
8. Kojodjojo P, Kanagaratnam P, Markides V, et al. Age-Related
changes in human left and right atrial conduction. J Cardiovasc
Electrophysiol. 2006;17(2):120–127.
9. Aronow WS. Heart disease and aging. Med Clin North Am.
2006;90(5):849–862.
10. Alexander NB, Dengel DR, Olson RJ, et al. Oxygen uptake (VO2)
kinetics and functional mobility performance in impaired
older adults. J Gerontol Biol Med Sci. 2003;58(8):734–739.
11. Iozzo P. Myocardial, perivascular, and epicardial fat. Diabetes
Care. 2011;34(suppl 2):S371–S379.
12. Lakatta EG, Sollott SJ. Perspectives on mammalian cardiovas­
cular aging: humans to molecules. Comp Biochem Physiol A
Mol Integr Physiol. 2002;132(4):699–722.
13. Elliott P, Spirito P. Prevention of hypertrophic cardiomyopathy-
related deaths: theory and practice. Heart. 2008;94(10):1269–1275.
14. Rieck AE, Cramariuc D, Staal EM, et al. Impact of hyperten­
sion on left ventricular structure in patients with asymp­
tomatic aortic valve stenosis (a SEAS substudy). J Hypertens.
2010;28(2):377–383.
15. Gosse P. Left ventricular hypertrophy as a predictor of cardio­
vascular risk. J Hypertens. 2005;23(S1):S27–S33.
16. Kubo T, Kitaoka H, Okawa M, et al. Hypertrophic cardiomy­
opathy in the elderly. Geriatr Gerontol Int. 2010;10(1):9–16.
17. Gradman AH, Alfayoumi F. From left ventricular hypertrophy
to congestive heart failure: management of hypertensive heart
disease. Prog Cardiovasc Dis. 2006;48(5):326–341.
18. Roberts WC, Shirani J. Comparison of cardiac findings at nec­
ropsy in octogenarians, nonagenarians, and centenarians. Am J
Cardiol. 1998;82(5):627–631.
19. Selzer A. Changing aspects of the natural history of valvular
aortic stenosis. N Engl J Med. 1987;317(2):91–98.
20. Seals DR, Monahan KD, Bell C, et  al. The aging cardio­
vascular system: changes in autonomic function at rest
and in response to exercise. Int J Sport Nutr Exerc Metab.
2001;11(suppl):S189–S195.
21. Rodeheffer RJ, Gerstenblith G, Becker LC, et al. Exercise cardiac
output is maintained with advancing age in healthy human sub­
jects: cardiac dilation and increased stroke volume compensate
for a diminished heart rate. Circulation. 1984;69(2):203–213.
22. Ghali JK, Liao Y, Cooper RS. Left ventricular hypertrophy in
the elderly. Am J Geriatr Cardiol. 1997;6(1):38–49.
23. Truong QA, Toepker M, Mahabadi AA, et al. Relation of left
ventricular mass and concentric remodeling to extent of coro­
nary artery disease by computed tomography in patients with­
out left ventricular hypertrophy: ROMICAT study. J Hypertens.
2009;27(12):2472–2482.
24. Bluemke DA, Kronmal RA, Lima JA, et al. The relationship of
left ventricular mass and geometry to incident cardiovascu­
lar events: The MESA (Multi-Ethnic Study of Atherosclerosis)
study. J Am Coll Cardiol. 2008;52(25):2148–2155.
25. Okin PM, Gerdts E, Wachtell K, et al. Relationship of left atrial
enlargement to persistence or development of ECG left ven­
tricular hypertrophy in hypertensive patients: implications
for the development of new atrial fibrillation. J Hypertens.
2010;28(7):1534–1540.
26. Campuzano R, Moya JL, Garcia-Lledo A, et al. Endothelial dys­
function, intima-media thickness and coronary reserve in rela­
tion to risk factors and Framingham score in patients without
clinical atherosclerosis. J Hypertens. 2006;24(8):1581–1588.
27. Kitzman DW, Edwards WE. Age-related changes in the anat­
omy of the normal human heart. J Gerontol Biol Med Sci.
1990;45(1):33–39.
28. Binder EF, Schechtman KB, Ehsani AA, et al. Effects of exer­
cise training on frailty in community dwelling older adults:
results of a randomized controlled clinical trial. J Am Geriatr
Soc. 2002;50(12):1921–1928.
29. Lakatta EG. Cardiovascular regulatory mechanism in advanced
age. Physiol Rev. 1993;73(2):413–467.
30. Shiaishi I, Takamatsu T, Minamikawa T, et al. Quantitative his­
tological analysis of the human sinoatrial node during growth
and aging. Circulation. 1992;85(6):2176–2184.
31. Erol-Yilmaz A, Schrama TA, Tanka JS, et al. Individual opti­
mization of pacing sensors improves exercise capacity with­
out influencing quality of life. Pacing Clin Electrophysiol.
2005;28(1):17–25.
32. Squires RW. Exercise Prescription for the High Risk Cardiac
Patient. Champaign, IL: Human Kinetics; 1998.
33. Tsakiris A, Doumas M, Nearchos N, et al. Aortic calcification
is associated with age and sex but not left ventricular mass in
essential hypertension. J Clin Hypertens. 2004;6(2):65–70.
34. Lindroos M, Kupari M, Valvanne J, et  al. Factors associated
with calcific aortic valve degeneration in the elderly. Eur Heart
J. 1994;15(7):865–870.
35. Robert L. Aging of the vascular wall and atherosclerosis. Exp
Gerontol. 1999;34(4):491–501.
36. Newman AB, Arnold AM, Burke GL, et al. Cardiovascular dis­
ease and mortality in older adults with small abdominal aor­
tic aneurysms detected by ultrasonography: the cardiovascular
health study. Ann Intern Med. 2001;134(3):182–190.
37. Yildiz A, Gur M, Yilmaz R, et al. The association of elasticity
indexes of ascending aorta and the presence and the severity of
coronary artery disease. Coron Artery Dis. 2008;19(5):311–317.
38. Wei JY, Epstein FH. Age and the cardiovascular system. N Engl
J Med. 1992;327(24):1735–1739.
39. Kitzman DW. Aging and the heart. Dev Cardiol.
1994;1(1):1–15.
40. Lakatta EB, Mitchell JH, Pomerance A, et  al. Human aging:
changes in structure and function III. Characteristics of spe­
cific cardiovascular diseases in the elderly. J Am Coll Cardiol.
1987;10(2 suppl A):42–47.
41. Lakatta EG. Altered autonomic modulation of cardiovas­
cular function with adult aging; perspectives from studies
ranging from man to cells. In: Stone HL, Weglicki WB, eds.
Pathobiology of Cardiovascular Injury. Boston: Martinus Nijhoff;
1985:441–460.
42. Turner MJ, Mier CM, Spina RJ, et al. Effects of aging and gen­
der on cardiovascular responses to isoproterenol. J Gerontol.
1999;54A(9):B393–B400.
43. Lakatta EG. Cardiovascular regulatory mechanisms in
advanced age. Physiol Rev. 1993;73(2):413–467.
44. Shimada K, Kitazumi T, Ogura H. Differences in age-
dependent effects of blood pressure on baroreflex sensi­
tivity between normal and hypertensive subjects. Clin Sci.
1986;70(5):763–766.
45. Guyton AC, Hall JE. Textbook of Medical Physiology. 12th ed.
Philadelphia: Saunders Elsevier; 2011.
46. Mukai S, Lipsitz LA. Orthostatic hypotension. Clin Geriatr
Med. 2002;18(2):253–268.

32
Section I  Building Baseline Knowledge
47. Vloet LCM, Pel-Little RE, Jansen PAF, et al. High prevalence
of postprandial and orthostatic hypotension among geriatric
patients admitted to Dutch hospitals. J Gerontol A Biol Sci Med
Sci. 2005;60A(10):1271–1277.
48. Gardin JM, Arnold AM, Bild DE, et al. Left ventricular dia­
stolic filling in the elderly: the cardiovascular health study. Am
J Cardiol. 1998;82(3):345–352.
49. Kitzman DW, Higginbotham MB, Sullivan MJ. Aging and
the cardiovascular response to exercise. Cardiol Elderly.
1993;1(6):543–550.
50. Green JS, Crouse SF. Endurance training, cardiovascular func­
tion, and the aged. Sports Med. 1993;16(5):331–341.
51. Cheitlin MD. Cardiovascular physiology—changes with age.
Am J Geriatr Cardiol. 2003;12(1):9–13.
52. Steinberg DH. Diastolic dysfunction of the left ventricle.
A review of the physiology, causes, diagnosis, treatment, and
implications. J Insur Med 1997;29(2):12–125.
53. Port S, Cobb FR, Coleman E, et al. Effect of age on the response
of the left ventricular ejection fraction to exercise. N Engl J
Med. 1980;303(20):1133–1137.
54. Nichols WW, O'Rourke MF, Avolio AP. Effects of age on ventricular-
vascular coupling. Am J Cardiol. 1985;55(9):1179–1184.
55. Devereux RB, Roman MJ, Paranicas M, et al. A population-
based assessment of left ventricular systolic dysfunction in
middle-aged and older adults: the Strong Heart Study. Am
Heart J. 2001;141(3):439–446.
56. Lakatta EG. Changes in cardiovascular function with aging.
Eur Heart J. 1990;11(suppl C):22–29.
57. Jurimae T, Jurimae J, Pihl E. Circulatory response to sin­
gle circuit weight and walking training sessions of similar
energy cost in middle-aged overweight females. Clin Physiol.
2000;20(2):143–149.
58. Vaitkevicius PV, Ebersold C, Muhammad S, et al. Effects of aer­
obic exercise training in community-based subjects aged 80 and
older: a pilot study. J Am Geriatr Soc. 2002;50(12):2009–2013.
59. Amara CE, Koval JJ, Paterson DH, et al. Lung function in older
humans: the contribution of body composition, physical activ­
ity, and smoking. Ann Hum Biol. 2001;28(5):522–537.
60. McRae H. Cardiovascular and pulmonary function. In: Spirduso
WW, Francis KL, MacRae PG, eds. Physical Dimensions of
Aging. 2nd ed. Champaign, IL: Human Kinetics; 2005:87–106.
61. LaPier T. Impaired aerobic capacity/endurance. In: Guccione
AA, Avers D, Wong RA, eds. Geriatric Physical Therapy. 3 rd ed.
St. Louis: Mosby; 2012:229–247.
62. Rossi A, Ganassini A, Tantucci C, et al. Aging and the respira­
tory system. Aging. 1996;8(3):143–161.
63. Zaugg M, Lucchinetti E. Respiratory function in the elderly.
Anesthesiol Clin North America. 2000;18(1):47–58.
64. Christiansen C. Impaird joint mobility. In: Guccione AA, Avers
D, Wong RA, eds. Geriatric Physical Therapy. 3 rd ed. St. Louis:
Mosby; 2012:248–262.
65. Davidson WR, Fee EC. Influence of aging on pulmonary hemo­
dynamics in a population free of coronary artery disease. Am J
Cardiol. 1990;65(22):1454–1458.
66. Babb TG. Mechanical ventilatory constraints in aging, lung
disease, and obesity: perspectives and brief review. Med Sci
Sports Exerc. 1999;31(suppl 1):12–22.
67. Tolep K, Kelsen SG. Effects of aging in respiratory skeletal
muscles. Clin Chest Med. 1993;14(3):363–378.
68. Brooks SV, Faulkner JA. Effects of aging on the structure and
function of skeletal muscle. In: Roussos C, ed. The Thorax.
New York: Academic Press; 1995:295–312.
69. Dias K. Physiology of the Cardiovascular and Pulmonary
Systems. In: Hillegass E, ed. Essentials of Cardiopulmonary
Physical Therapy. 3 rd ed. St. Louis: Elsevier Saunders;
2011:27–46.
70. Zeleznik J. Normative aging of the respiratory system. Clin
Geriatr Med. 2003;19(1):1–18.
71. Camhi SL, Enright PL. How to assess pulmonary function in
older persons. J Respir Dis. 2000;21(6):395.
72. Stulberg M, Carrieri-Kohlman V. Conceptual approach
to the treatment of dyspnea: focus on the role of exercise.
Cardiopulmonary Phys Ther. 1992;3(1):9–12.
73. Spector N, Connolly MA, Carlson KK. Dyspnea: apply­
ing research to bedside practice. AACN Adv Crit Care.
2007;18(1):45–60.
74. Maher D, Hemming L. Palliative care for breathless patients in
the community. Br J Community Nurs. 2005;10(9):414–418.
75. Pollock ML, Wilmore JH, eds. Exercise in Health and Disease.
Philadelphia: Saunders; 1990.
76. VanBeveran PJ, Avers D. Exercise and physical activity for older
adults. In: Guccione AA, Avers D, Wong RA, eds. Geriatric
Physical Therapy. 3 rd ed. St. Louis: Mosby; 2012:64–86.
77. Host HH, Sinacore DR, Turner MJ, et al. Oxygen uptakes at
preferred gait velocities of frail elderly subjects. Phys Ther.
1996;76(4):S69.
78. Wanderley FAC, Oliveira J, Mota J, et al. Six-minute walk dis­
tance (6MWD) is associated with body fat, systolic blood pres­
sure, and rate-pressure product in community dwelling elderly
subjects. Arch Gerontol Geriatr. 2011;52(2):206–210.
79. Ellestad MH. Stress Testing: Principles and Practice. 5th ed.
Oxford: Oxford University Press; 2003.
80. Housh TJ, Housh DJ, DeVries HA. Applied Exercise and Sport
Physiology. 2nd ed. Scottsdale, AZ: Holcomb Hathaway; 2006.
81. Tonino RP, Driscoll PA. Reliability of maximal and submaximal
parameters of treadmill testing for the measurement of physical
training in older persons. J Gerontol. 1988;42(2):M101–M104.
82. Materson BJ. Isolated systolic blood pressure: new answers,
more questions. J Am Geriatr Soc. 1991;39(12):1237–1238.
83. Applegate WB, Davis BR, Black HR. Prevalence of pos­
tural hypotension at baseline in the systolic hypertension
in the elderly program (SHEP) cohort. J Am Geriatr Soc.
1991;39(11):1057–1064.
84. Naughton J. Exercise Testing: Physiological, Biomechanical, and
Clinical Principles. Mount Kisco, NY: Futura; 1988.
85. Crawford K, McNamara SB, Vogel W, et al. Pulmonary medica­
tions. In: Hillegass E, ed. Essentials of Cardiopulmonary Physical
Therapy. 3 rd ed. St. Louis: Elsevier Saunders; 2011:515–533.
86. Matsuda PN, Shumway-Cook A, Ciol MA. The effects of a
home-based exercise program on physical function in frail
older adults. J Geriatr Phys Ther. 2010;33(2):78–84.
87. Tse MMY, Wan VTC, Ho SSK. Physical exercise: does it help in
relieving pain and increasing mobility among older adults with
chronic pain? J Clin Nurs. 2011;20(5/6):635–644.
88. Hagberg JM, Allen WK, Seals DR. A hemodynamic compar­
ison of young and older endurance athletes during exercise.
J Appl Physiol. 1985;58(6):2041–2046.
89. Ekstrum JA, Black LL, Paschal KA. Effects of a thoracic mobil­
ity and respiratory exercise program on pulmonary func­
tion and functional capacity in older adults. Phys Occup Ther
Geriatr. 2009;27(4):310–327.
90. Steib S, Schoene D, Pfeifer K. Dose-response relationship of
resistance training in older adults: a meta-analysis. Med Sci
Sports Exerc. 2010;42(5):902–914.

Chapter 2  Aging and Activity Tolerance: Implications for Orthotic and Prosthetic Rehabilitation
33
91. Fleg JL, Morrell CH, Bos AG, et al. Accelerated longitudinal
decline of aerobic capacity in healthy older adults. Circulation.
2005;112(5):674–682.
92. Yarasheski KE. Managing sarcopenia with progressive resis­
tance exercise training. J Nutr Health Aging. 2002;6(5):349–356.
93. Casaburi R, Patessio A, Ioli F. Reductions in exercise lac­
tic acidosis and ventilation as a result of exercise training in
patients with obstructive lung disease. Am Rev Respir Dis.
1991;143(1):9–18.
94. Marcus RL, Westlen-Boyer K, LaStayo P. Impaired muscle per­
formance. In: Guccione AA, Avers D, Wong RA, eds. Geriatric
Physical Therapy. 3 rd ed. St. Louis: Mosby; 2012:263–271.
95. Borg G. Perceived exertion as an indicator of somatic stress.
Scand J Rehabil Med. 1970;2(3):92–97.
96. Borg G, Ottoson D. The Perception of Exertion in Physical
Work. London: Macmillan; 1986.
97. Fletcher GF, Mills WC, Taylor WC. Update on exercise stress
testing. Am Fam Physician. 2006;74(10):1749–1754.
98. Kline GM, Porcari JP, Hintermeister R, et  al. Estimation of
VO2max from a one-mile track walk, gender, age, and body
weight. Med Sci Sports Exerc. 1987;19(3):253–259.
99. Butland RJ, Pang J, Gross ER, et  al. Two-, six-, and
12-minute walking tests in respiratory disease. BMJ.
1982;284(6329):1607–1608.
100. Guyatt GH, Sullivan MJ, Thompson PJ, et al. The 6-minute
walk test: a new measure of exercise capacity in patients with
chronic heart failure. Can Med Assoc J. 1985;132(8):9919–9923.
101. Smith EL, Gilligan C. Physical activity perception for the older
adult. Phys Sports Med. 1993;11:91–101.
102. Prentice WE. Armheim's Principles of Athletic Training: a
Competency Based Approach. 14th ed. New York: McGraw-Hill;
2011.
103. Durstine JL, Moore GE, Painter PL, et  al. ACSM's Exercise
Management for Persons with Chronic Diseases and Disabilities.
3 rd ed. Champaign, IL: Human Kinetics; 2009.
104. Ehrman JK, deJong A, Sanderson B, et al., eds. ACSM's Resource
Manual for Guidelines for Exercise Testing and Prescription.
6th ed. Philadelphia: Lippincott Williams & Wilkins; 2010.
105. Cress ME, Buchner DM, Prohaska T, et  al. Best practices
statement: physical activity programs and behavior coun­
seling in older adult populations. Med Sci Sports Exerc.
2004;36(11):1997–2003.
106. Mandic S, Riess K, Haykowsky MJ. Exercise training for indi­
viduals with coronary artery disease or heart failure. Physiother
Can. 2006;58(1):21–29.
107. Seals DR, Hagberg JM, Hurley BF, et al. Effects of endurance
training on glucose tolerance and plasma lipid levels in older
men and women. JAMA. 1984;252(5):645–649.
108. Lewis CB, Kellems S. Musculoskeletal changes with age: clinical
implications. In: Lewis CB, ed. Aging the Health Care Challenge.
4th ed. Philadelphia: F.A. Davis; 2002:104–126.
109. Avers D, Brown M. Strength training for the older adult.
J Geriatr Phys Ther. 2009;32(4):148–152, 158.
110. Hunter GR, McCarthy JP, Bamman MM. Effects of resistance
training on older adults. Sports Med. 2004;34(5):329–348.
111. Palta AF. Neurobiomechanical bases for the control of human
movement. In: Bronstein A, Brandt T, Woollacott M, eds.
Clinical Disorders of Balance, Posture, and Gait. London:
Arnold; 1996:19–40.
112. Bianchi L, Angelini D, Orani GP, et  al. Kinematic coordi­
nation in human gait: relation to mechanical energy cost.
J Neurophysiol. 1998;79(4):2155–2170.
113. Perry J, Burnfield JM. Basic functions. In: Perry J, Burnfield
JM, eds. Gait Analysis: Normal and Pathological Function.
2nd ed. Thorofare, NJ: Slack; 2010:19–48.
114. Olney SJ, Eng J. Gait. In: Levangie PK, Norkin CC, eds. Joint
Structure and Function: A Comprehensive Analysis. 5th ed.
Philadelphia: F.A. Davis; 2011:524–567.
115. Winter DA, Quanbury AO, Reimer GD. Analysis of instanta­
neous energy of normal gait. J Biomech. 1976;9(4):252–257.
116. Rose J, Gamble JG. Human Walking. 3 rd ed. Philadelphia:
Lippincott Williams & Wilkins; 2005.
117. Waters RL. Energy expenditure. In: Perry J, Burnfield JM,
eds. Gait Analysis: Normal and Pathological Function. 2nd ed.
Thorofare, NJ: Slack; 2010:483–518.
118. Studenski S, Perera S, Kushang P, et al. Gait speed and survival
in older adults, JAMA. 2011;305(1):50–58.
119. Fritz S, Lusardi M. White paper: walking speed: the sixth vital
sign. J Geriatr Phys Ther. 2009;32(2):46–49.
120. Brach JS, VanSwearingen JM, Newman AB, et al. Identifying
early decline of physical function in community-dwelling older
women: performance-based and self-report measures. Phys
Ther. 2002;82(4):320–328.
121. Cesari M, Kritchevsky SB, Newman AB, et al. Added value of
physical performance measures in predicting adverse health-
related events: results from the Health, Aging and Body
Composition Study. J Am Geriatr Soc. 2009;57(2):251–259.
122. Cesari M, Kritchevsky SB, Penninx BW, et al. Prognostic value
of usual gait speed in well-functioning older people—results
from the health, aging and body composition study. J Am
Geriatr Soc. 2005;53(10):1675–1680.
123. Brach JS, VanSwearingen JM, FitzGerald SJ, et al. The relation­
ship among physical activity, obesity, and physical function in
community-dwelling older women. Prev Med. 2004;39(1):74–80.
124. Brach JS, FitzGerald S, Newman AB, et  al. Physical activ­
ity and functional status in community-dwelling older
women: a 14-year prospective study. AMA Arch Intern Med.
2003;163(21):2565–2571.
125. Cawthon PM, Fox KM, Gandra SR, et  al. Clustering of
strength, physical function, muscle, and adiposity character­
istics and risk of disability in older adults. J Am Geriatr Soc.
2011;59(5):781–787.
126. Purser JL, Weinberger M, Cohen HJ, et al. Walking speed pre­
dicts health status and hospital costs for frail elderly male vet­
erans. J Rehabil Res Dev. 2005;42(4):535–545.
127. Rabadi MH, Blau A. Admission ambulation velocity pre­
dicts length of stay and discharge disposition following
stroke in an acute hospital. Neurorehabil Neural Repair.
2005;19(1):20–26.
128. Studenski S, Perera S, Patel K, et al. Gait speed and survival in
older adults. JAMA. 2011;305(1):50–58.
129. Chui KK, Lusardi MM. Spatial and temporal parameters of self-
selected and fast walking speeds in healthy community-living
adults aged 72-98 years. J Geriatr Phys Ther. 2010;33(4):173–183.
130. Steffen TM, Hacker TA, Mollinger L. Age- and gender-related
test performance in community-dwelling elderly people: six-
minute walk test, berg balance scale, timed up & go test, and
gait speeds. Phys Ther. 2002;82(2):128–137.
131. Bohannon RW. Comfortable and maximum walking speed of
adults aged 20-79 years. Age Ageing. 1997;26(1):15–19.
132. Wert DM, Brach J, Perera S, et  al. Gait biomechanics, spa­
tial and temporal characteristics, and the energy cost of
walking in older adults with impaired mobility. Phys Ther.
2010;90(7):977–985.

34
Section I  Building Baseline Knowledge
133. Lusardi MM, Pellecchia GL, Schulman M. Functional perfor­
mance in community living older adults. J Geriatr Phys Ther.
2003;26(3):14–22.
134. Ko S, Hausdorff JM, Ferrucci L. Age-associated differences in
the gait pattern changes of older adults during fast-speed and
fatigue conditions: results from the Baltimore Longitudinal
Study of Ageing. Age Ageing. 2010;39(6):688–694.
135. Deathe AB, Miller WC. The L Test of Functional Mobility:
measurement properties of a modified version of the timed
“up & go” test designed for people with lower-limb amputa­
tions. Phys Ther. 2005;85(7):626–635.
136. Rossier P, Wade DT. Validity and reliability comparison of 4
mobility measures in patients presenting with neurologic
impairment. Arch Phys Med Rehabil. 2001;82(1):9–13.
137. van Hedel HJ, Wirz M, Dietz V. Assessing walking ability in
subjects with spinal cord injury: validity and reliability of 3
walking tests. Arch Phys Med Rehabil. 2005;86(2):190–196.
138. Studenski S, Perera S, Wallace D. Physical performance measures
in the clinical setting. J Am Geriatr Soc. 2003;51(3):314–322.
139. Ries JD, Echternach JL, Nof L, et al. Test-retest reliability and
minimal detectable change scores for the timed “up & go”
test, the six-minute walk test, and gait speed in people with
Alzheimer disease. Phys Ther. 2009;89(6):569–579.
140. Hollman JH, Beckman BA, Brandt RA, Merriwether EN,
Williams RT, Nordrum JT. Minimum detectable change in
gait velocity during acute rehabilitation following hip fracture.
J Geriatr Phys Ther. 2008;31(2):53–56.
141. Tilson JK, Sullivan KJ, Cen SY, et  al. Meaningful gait speed
improvement during the first 60 days poststroke: minimal clin­
ically important difference. Phys Ther. 2010;90(2):196–208.
142. Water RL, Mulroy SJ. Energy expenditure of walking in indi­
viduals with lower limb amputation. In: Smith DC, Michael
JW, Bowker JH, eds. Atlas of Amputations and Limb Deficiency:
Surgical, Prosthetics and Rehabilitation Principles. 3 rd ed.
Rosemont, IL: American Academy of Orthopedic Surgeons;
2004:395–408.
143. Perry J. Normal and pathological gait. In: Hsu JD, Michael
JW, Fisk JR, eds. AAOS Atlas of Orthoses and Assistive Devices.
4th ed. Philadelphia: Mosby Elsevier; 2008:61–82.
144. Thompson WR, Gordon NF, Pescatello LS, eds. ACSM's
Guidelines for Exercise Testing and Prescription. 8th
ed.Philadelphia: Lippincott Williams & Wilkins; 2010.
145. Kalapotharakos VI. Aerobic exercise in older adults: effects on
VO2max and functional performance. Crit Rev Phys Rehabil Med.
2007;19(3):213–225.
146. Sergi G, Coin A, Sarti S, et al. Resting VO2, maximal VO2 and
metabolic equivalents in free-living healthy elderly women.
Clin Nutr. 2010;29(1):84–88.
147. Leeuwenburgh C, Heinecke JW. Oxidative stress and antioxi­
dants in exercise. Curr Med Chem. 2001;8(7):829–838.
148. Fleg JL, Morrell CH, Bos AG, et al. Accelerated longitudinal
decline of aerobic capacity in healthy older adults. Circulation.
2005;112(5):674–682.
149. Saltin B, Blomquist G, Mitchell JH, et  al. Response to sub­
maximal and maximal exercise after bedrest and training.
Circulation. 1968;38(suppl 7):1–78.
150. Davis JA. Anaerobic threshold: review of the concept
and directions for future research. Med Sci Sports Exerc.
1985;17(1):6–8.
151. McArdle WD, Katch FI, Katch VL. Exercise Physiology: Energy,
Nutrition, and Human Performance. 6th ed. Philadelphia:
Lippincott Williams & Wilkins; 2006.
152. Rose J, Gamble JG, Medeiros J, et al. Energy cost of walking
in normal children and in those with cerebral palsy: com­
parison of heart rate and oxygen uptake. J Pediatr Orthop.
1989;9(3):276–279.
153. Rose GK. Clinical gait assessment. J Med Eng Technol.
1983;7(6):273–279.
154. Eston R, Connolly D. The use of ratings of perceived exertion
for exercise prescription in patients receiving beta-blocker
therapy. Sports Med. 1996;21(3):176–190.
155. Faulhaber M, Flatz M, Burtscher M. Beta-blockers may pro­
voke oxygen desaturation during submaximal exercise at
moderate altitudes in elderly persons. High Alt Med Biol.
2003;4(4):475–478.
156. Steven MM, Capell HA, Sturrock RD, et al. The physiological
cost of gait (PCG): a new technique for evaluating non-steroidal
anti-inflammatory drugs in rheumatoid arthritis. Br J Rheumatol.
1983;22(3):141–145.
157. Butler P, Engelbrecht M, Major RE, et al. Physiological cost index
of walking for normal children and its use as an indicator of
physical handicap. Dev Med Child Neurol. 1984;26(5):607–612.
158. Nene AV. Physiological cost index of walking in able-bodied
adolescents and adults. Clin Rehabil. 1993;7(4):319–326.
159. Peebles KC, Woodman-Aldridge AD, Skinner MA. The physi­
ological cost index in elderly subjects during treadmill and
floor walking. N Z J Physiother. 2003;3(1):11–16.
160. Hamzeh MA, Bowker P, Sayeqh A, et al. The energy cost of
ambulation using 2 types of walking frames. Clin Rehabil.
1988;2:119–123.
161. Johnson CA, Burridge JH, Strike PW, et al. The effect of com­
bined use of botulinum toxin type A and functional elec­
trical stimulation in the treatment of spastic foot drop after
stroke: a preliminary investigation. Arch Phys Med Rehabil.
2004;85(6):902–909.
162. Kottink AI, Oostendorp LJ, Buurke JH, et  al. The orthotic
effect of functional electrical stimulation on the improvement
of walking in stroke patients with dropped foot: a systematic
review. Artif Organs. 2004;28(6):577–586.
163. Burridge JH, Taylor PN, Hagan SA, et al. The effects of com­
mon peroneal nerve stimulation on the effort and speed of
walking: a randomized controlled clinical trial with chronic
hemiplegic patients. Clin Rehabil. 1997;11(3):201–210.
164. Burridge J, Taylor P, Hagan S, et  al. Experience of clinical
use of the Odstock dropped foot stimulator. Artif Organs.
1997;21(3):254–260.
165. Carmick J. Clinical use of neuromuscular electrical stimulation
for children with cerebral palsy: lower extremity. Phys Ther.
1993;73(8):505–513.
166. Nene AV, Evans GA, Patrick JH. Simultaneous multiple
operations for spastic diplegia: Outcome and functional
assessment of walking in 18 patients. J Bone Joint Surg Br.
1993;75(3):488–494.
167. Yang L, Condie DN, Granat MP, et al. Effects of joint motion
constraints on normal subjects and their implications on the
further development of hybrid FES orthosis for paraplegic per­
sons. J Biomech. 1996;29(2):217–226.
168. Nene AV, Jennings SJ. Physiological cost index of paraple­
gic locomotion using the ORLAU ParaWalker. Paraplegia.
1992;30(4):246–252.
169. Stallard J, Major RE. The influence of stiffness on paraple­
gic ambulation and its implications for functional elec­
trical stimulation walking systems. Prosthet Orthot Int.
1995;19(2):108–114.

Chapter 2  Aging and Activity Tolerance: Implications for Orthotic and Prosthetic Rehabilitation
35
170. Engsberg JR, Herbert LM, Grimston SK, et al. Relation among
indices of effort and oxygen uptake in below knee and able-bodied
children. Arch Phys Med Rehabil. 1994;75(12):1335–1341.
171. Chin T, Sawamura S, Fujita H, et al. The efficacy of physiologi­
cal cost index measurement of a subject walking with an intel­
ligent prosthesis. Prosthet Orthot Int. 1999;23(10):45–49.
172. Hachisuka K, Umezu Y, Ohmine S, et al. Subjective evaluations
and objective measurements of the ischial-ramal containment
prosthesis. J UOEH. 1999;21(2):107–118.
173. Herbert JS, Liggins AB. Gait evaluations of an automatic stance
control knee orthosis in a patient with post-poliomyelitis. Arch
Phys Med Rehabil. 2005;86(8):1676–1680.
174. Hagberg K, Tranberg R, Zügner R, Danielsson A.
Reproducibility of the Physiological Cost Index among indi­
viduals with a lower-limb amputation and healthy adults.
Physiother Res Int. 2011;16(2):92–100.
175. Danielsson A, Willen C, Sunnerhagen KS. Measurement of
energy cost by the physiological cost index in walking after
stroke. Arch Phys Med Rehabil. 2007;88(10):1298–1303.
176. Genin JJ, Bastien GJ, Lopez N, et al. Does the physiological
cost index reflect the cost of walking? Arch Physiol Biochem.
2004;112(suppl):73.
177. Morgan DW, Tseh W, Caputo JL, et al. Longitudinal stratifica­
tion of gait economy in young boys and girls: the locomotion
energy and growth study. Eur J Appl Physiol. 2004;91(1):30–34.
178. Waters RL, Hislop HJ, Thomas L, et al. Energy cost of walk­
ing in normal children and teenagers. Dev Med Child Neurol.
1983;25(2):184–188.
179. Waters RL, Lunsford BR, Perry J, et al. Energy-speed relationship
of walking: standard tables. J Orthop Res. 1988;6(2):215–222.
180. Waters RL, Hislop HJ, Perry J, et al. Comparative cost of walk­
ing in young and old adults. J Orthop Res. 1983;1(1):73–76.
181. Aoyagi Y, Togo F, Matsuki S, et al. Walking velocity measured
over 5 m as a basis of exercise prescription for the elderly: pre­
liminary data from the Nakanojo Study. Eur J Appl Physiol.
2004;93(1–2):217–223.
182. Malatesta D, Simar D, Dauvilliers Y, et  al. Aerobic determi­
nants of the decline in preferred walking speed in healthy,
active 65- and 80-year-olds. Eur J Physiol [Pflugers Arch].
2004;447(6):915–921.
183. Astrand A, Astrand I, Hallback I, et al. Reduction in maximal
oxygen uptake with age. J Appl Physiol. 1973;35(5):649–654.
184. Binder EF, Schechtman KB, Ehsani AA, et al. Effects of exer­
cise training on frailty in community-dwelling older adults:
results of a randomized, controlled trial. J Am Geriatr Soc.
2002;50(12):1921–1928.
185. Corcoran PJ, Gelmanan B. Oxygen reuptake in normal and hand­
icapped subjects in relation to the speed of walking beside a veloc­
ity controlled cart. Arch Phys Med Rehabil. 1970;51(2):78–87.
186. Holt KG, Hamill J, Andres RO. Predicting the mini­
mal energy cost of human walking. Med Sci Sports Exerc.
1991;23(4):491–498.
187. Duff Raffaele M, Kerrigan DC, Corcoran PJ, et al. The propor­
tional work of lifting the center of mass during walking. Am J
Phys Med. 1996;75(5):375–379.
188. Hanada E, Kerrigan DC. Energy consumption during level
walking with arm and knee immobilized. Arch Phys Med
Rehabil. 2001;82(9):1251–1254.
189. Bruinings AL, van den Berg-Emons HJ, Buffart LM, et  al.
Energy cost and physical strain of daily activities in adoles­
cents and young adults with myelomeningocele. Dev Med Child
Neurol. 2007;49(9):672–677.
190. Detrembleur C, Dierick F, Stoquart G, et  al. Energy cost,
mechanical work, and efficiency of hemiparetic walking. Gait
Posture. 2003;18(2):47–55.
191. Brophy LS. Gait in cerebral palsy. Orthop Phys Ther Clin North
Am. 2001;10(1):55–76.
192. Patrick JH. The case for gait analysis as part of the management of
incomplete spinal cord injury. Spinal Cord. 2003;41(9):479–482.
193. Jeans KA, Browne RH, Karol LA. Effect of amputation level
on energy expenditure during overground walking by chil­
dren with an amputation. J Bone Joint Surg. 2011;93(1):49–56.
194. Bell KL, Davies PS. Energy expenditure and physical activity of
ambulatory children with cerebral palsy and of typically devel­
oping children. Am J Clin Nutr. 2010;92(2):313–319.
195. Inman VT, Ralston HJ, Todd F. Human Walking. Baltimore:
Waverly; 1981.
196. Waters RL, Lunsford BR. Energy expenditure of normal and
pathological gait: application to orthotic prescription. In:
Bowker JH, Michael JW, eds. Atlas of Orthotics. St. Louis:
Mosby; 1985:151–159.
197. Buckon CE, Thomas SS, Jakobson-Huston S, et al. Comparison
of three ankle-foot orthosis configurations for children with
spastic diplegia. Dev Med Child Neurol. 2004;46(9):590–598.
198. Franceschini M, Massucci M, Ferrari L, et  al. Effects of an
ankle-foot orthosis on spatiotemporal parameters and energy
cost of hemiparetic gait. Clin Rehabil. 2003;17(4):368–372.
199. Kaufman KR, Irby SE, Mathewson JW, et al. Energy-efficient
knee-ankle-foot orthosis: a case study. J Prosthet Orthot.
1996;8(3):79–85.
200. Waters RL, Campbell J, Thomas L, et al. Energy costs of walk­
ing in lower-extremity plaster casts. J Bone Joint Surg Am.
1982;64(6):896–899.
201. Abudulhadi HM, Kerrigan DC, LaRaia PJ. Contralateral shoe-
lift: effect on oxygen cost of walking with an immobilized knee.
Arch Phys Med Rehabil. 1996;77(7):760–762.
202. Morganti B, Scivoletto G, Ditunno P, et  al. Walking index for
spinal cord injury (WISCI): criterion validation. Spinal Cord.
2005;43(1):27–33.
203. Hussey RW, Stauffer ES. Spinal cord injury: requirements for
ambulation. Arch Phys Med Rehabil. 1973;54(12):544–547.
204. Yakura JS, Waters RL, Adkins RH. Changes in ambulation
parameters in spinal cord injury individuals following rehabili­
tation. Paraplegia. 1990;28(6):364–370.
205. Waters RL, Yakura JS, Adkins RH. Gait performance after
spinal cord injury. Clin Ortop. 1993;228:87–96.
206. Johnston TE, Smith BT, Betz RR. Strengthening of partially
denervated knee extensors using percutaneous electric stimu­
lation in a young man with spinal cord injury. Arch Phys Med
Rehabil 2005;86(5):1037–1042.
207. Johnston TE, Finson RL, Smith BT, et al. Technical perspec­
tive Functional electrical stimulation for augmented walking
in adolescents with incomplete spinal cord injury. J Spinal Cord
Med. 2003;26(4):390–400.
208. Brissot R, Gallien P, Le Bot M, et al. Clinical experience with
functional electrical stimulation-assisted gait with parastep in
spinal cord-injured patients. Spine. 2000;25(4):501–508.
209. Solomonow M, Baratta R, D'Ambrosia R. Standing and walk­
ing after spinal cord injury: experience with the reciprocating
gait orthosis powered by electrical muscle stimulation. Top
Spinal Cord Inj Rehabil. 2000;5(4):29–53.
210. Lam T, Eng JJ, Wolfe DL, et al. A systematic review of the effi­
cacy of gait rehabilitation strategies for spinal cord injury. Top
Spinal Cord Inj Rehabil. 2007;13(1):32–57.

36
Section I  Building Baseline Knowledge
211. Atrice MB. Lower extremity orthotic management for the
spinal-cord-injured client. Top Spinal Cord Inj Rehabil.
2000;5(4):1–10.
212. Knutson J, Audu M, Triolo R. Interventions for mobility and
manipulation after spinal cord injury: a review of orthotic
and neuroprosthetic options. Top Spinal Cord Inj Rehabil.
2006;11(4):61–81.
213. Rasmussen AA, Smith KM, Damiano DL. Biomechanical
evaluation of the combination of bilateral stance-control
knee-ankle-foot orthoses and a reciprocating gait ortho­
sis in an adult with a spinal cord injury. J Prosthet Orthot.
2007;19(2):42–47.
214. Yang L, Granat MH, Paul JP, et  al. Further development of
hybrid functional electrical stimulation orthoses. Artif Organs.
1997;21(3):183–187.
215. Ryerson SD. Hemiplegia. In: Umphred DA, ed. Neurological
Rehabilitation. 5th ed. St. Louis: Mosby Elsevier; 2006:857–901.
216. da Cunha IT, Lim PA, Qureshy H, et al. Gait outcomes after
acute stroke rehabilitation with supported treadmill ambula­
tion training: a randomized controlled pilot study. Arch Phys
Med Rehabil. 2002;83(9):1258–1265.
217. Chen G, Patten C, Kothari DH, et al. Gait deviations associated
with post-stroke hemiparesis: improvement during treadmill
walking using weight support, speed, support stiffness, and
handrail hold. Gait Posture. 2005;22(1):57–62.
218. Courbon A, Calmels P, Roche F, et al. Relationship between
maximal exercise capacity and walking capacity in adult
hemiplegic stroke patients. Am J Phys Med Rehabil.
2006;85(5):436–442.
219. Mauritz KH, Hesse S. Neurological rehabilitation of gait and
balance disorders. In: Bronstein AM, Brandt T, Woollacott MH,
eds. Clinical Disorders of Balance, Posture and Gait. London:
Arnold; 1996:236–250.
220. Ward KH, Meyers MC. Exercise performance of lower extrem­
ity amputees. Sports Med. 1995;20(4):207–214.
221. Lin-Chan S, Nielsen DH, Shurr DG, et  al. Physiological
responses to multiple speed treadmill walking for Syme
vs. transtibial amputation—a case report. Disabil Rehabil.
2003;25(23):1333–1338.
222. Winter DA, Sienko SE. Biomechanics of below-knee amputee
gait. J Biomech. 1988;21(5):361–367.
223. Torburn L, Powers CM, Guiterrez R, et al. Energy expenditure
during ambulation in dysvascular and traumatic below-knee
amputees: a comparison of five prosthetic feet. J Rehabil Res
Dev. 1995;32(2):111–119.
224. Waters RL, Perry J, Antonelli D, et al. The energy cost of walk­
ing of amputees: influence of level of amputation. J Bone Joint
Surg. 1976;58(1):42–46.
225. Esqienazi A. Geriatric amputee rehabilitation. Clin Geriatr
Med. 1993;9(5):731–743.
226. Ganguli S, Datta SR, Chatterjee B. Performance evalua­
tion of amputee-prosthesis system in below knee amputees.
Ergonomics. 1973;16(6):797–810.
227. Gailey RS, Wenger MA, Raya M, et al. Energy expenditure of
transtibial amputees during ambulation at self-selected pace.
Prosthet Orthot Int. 1994;18(2):84–91.
228. Otis JC, Lane JM, Kroll MA. Energy cost during gait in
osteosarcoma patients after resection and knee replace­
ment and after above the knee amputation. J Bone Joint Surg.
1985;67A(4):606–611.
229. Fisher SV, Gullickson G. Energy cost of ambulation in health
and disability: a literature review. Arch Phys Med Rehabil.
1978;59(3):124–133.
230. Jaeger SM, Vos LD, Rispens P, et al. The relationship between
comfortable and most metabolically efficient walking speed
in persons with unilateral above knee amputations. Arch Phys
Med Rehabil. 1993;74(5):521–525.
231. Molen NH. Energy/speed relation of below knee amputees
walking on a motor driven treadmill. Int Z Angew Physiol.
1973;31(3):173–185.
232. Czerniecki JM. Rehabilitation of limb deficiency. 1: Gait and
motion analysis. Arch Phys Med Rehabil 1996;77(suppl 35):
S29–S37, S81–S82.
233. May BJ. Lower extremity prosthetic management. In:
Amputation and Prosthetics: A Case Study Approach. 2nd ed,
Philadelphia: F.A. Davis; 2002.
234. Andrews KL. Rehabilitation in limb deficiency. 3: The geriatric
amputee. Arch Phys Med Rehabil 1996;77(3):S14–S17.
235. Torburn L, Perry J, Ayyappa E, et al. Below knee amputee gait
with dynamic elastic response feet: a pilot study. J Rehabil Res
Dev. 1990;27(4):369–384.
236. Dubow LL, Witt PL, Kadaba MP, et  al. Oxygen consump­
tion of elderly persons with bilateral below knee amputation:
ambulation vs. wheelchair propulsion. Arch Phys Med Rehabil.
1983;64(6):255–259.
237. Wu YJ, Chen SY, Lin MC, et al. Energy expenditure of wheel­
ing and walking during prosthetic rehabilitation in a woman
with bilateral transfemoral amputation. Arch Phys Med Rehabil.
2001;82(2):265–269.
238. Nissen SJ, Newman WP. Factors influencing reintegration
to normal living after amputation. Arch Phys Med Rehabil.
1992;73(6):548–551.
239. Nitz JC. Rehabilitation outcomes after bilateral lower limb
amputation for vascular disease. Physiother Theory Pract.
1993;9(3):165–170.
240. Hofstad C, Van der Linde H, Van Limbeek J, et al. Prescription of
Prosthetic Ankle Foot Mechanisms After Lower Limb Amputation.
Washington, DC: Cochrane Library; 2004. 003978.
241. Zmitrewicz RJ, Neptune RR, Walden JG, et al. The effect of
foot and ankle prosthetic components on braking and propul­
sive impulses during transtibial amputee gait. Arch Phys Med
Rehabil. 2006;87(10):1334–1339.
242. Gitter A, Czerniecki JM, DeGroot DM. Biomechanical analysis
of the influence of prosthetic feet on below knee amputee walk­
ing. Am J Phys Med Rehabil. 1991;70(3):142–148.
243. Hsu MJ, Nielsen DH, Yack JH, et al. Physiological measure­
ments of walking and running in people with transtibial ampu­
tations with 3 different prostheses. J Orthop Sports Phys Ther.
1999;29(9):526–533.
244. Pomeranz B, Adler U, Shenoy N, et al. Prosthetics and orthotics
for the older adult with a physical disability. Clin Geriatr Med.
2006;22(2):377–394.
245. Barth DG, Shumacher L, Sienko-Thomas S. Gait analysis and
energy cost of below-knee amputees wearing six different pros­
thetic feet. J Prosthet Orthot. 1992;4(2):63–75.
246. McFarlane PA, Nielsen DH, Shurr DG, et al. Gait comparisons
for below-knee amputees using a FlexFoot versus a conven­
tional prosthetic foot. J Prosthet Orthot. 1991;3(4):150–161.
247. Wirta RW, Mason R, Calvo K, et  al. Effect on gait using
various prosthetic ankle foot devices. J Rehabil Res Dev.
1991;28(2):13–24.
248. Czerniecki JM, Gitter A. The impact of energy storing pros­
thetic feet on below knee amputation gait. Arch Phys Med
Rehabil. 1989;70(13):918.
249. Czerniecki JM, Gitter A, Murno C. Joint moment and mus­
cle power output characteristics of below knee amputees

Chapter 2  Aging and Activity Tolerance: Implications for Orthotic and Prosthetic Rehabilitation
37
during running: the influence of energy storing prosthetic feet.
J Biomech. 1991;24(1):63–75.
250. Casillas JM, Dulieu V, Cohen M, et al. Bioenergetic compari­
son of a new energy storing foot and SAHD foot in traumatic
below-knee vascular amputations. Arch Phys Med Rehabil.
1995;76(1):39–44.
251. Torburn L, Schweiger GP, Perry J, et al. Below knee amputee gait
in stair climbing: a comparison of stride characteristics using
five different prosthetic feet. Clin Ortop. 1994;303:185–192.
252. Perry J, Burnfield JM, Newsam CJ, et  al. Energy expendi­
tures and gait characteristics of a bilateral amputee walking
with C-leg prostheses compared with stubby and con­
ventional articulating prostheses. Arch Phys Med Rehabil.
2004;85(10):1711–1717.
253. Hafner BJ, Smith DG. Differences in function and safety
between Medicare Functional Classification Level-2 and -3
transfemoral amputees and influence of prosthetic knee joint
control. J Rehabil Res Dev. 2009;46(3):417–433.
254. Berry D, Olson MD, Larntz K. Perceived stability, function,
and satisfaction among transfemoral amputees using micro­
processor and nonmicroprocessor controlled prosthetic knees:
a ­multicenter survey. J Prosthet Orthot. 2009;21(1):32–42.

38
3
Motor Control, Motor Learning, and Neural Plasticity
in Orthotic and Prosthetic Rehabilitation
Michelle M. Lusardi and Donna M. Bowers
3
LEARNING OBJECTIVES
On completion of this chapter, the reader will be able to:
1. Discuss the strengths, limitations, and implementation for
practice of current models of motor control.
2. Compare and contrast the tenets of current motor learning
theories.
3. Discuss the role physical therapy interventions based on
knowledge of motor control and motor learning in aug­
menting neural plasticity after brain injury.
4. Apply principles of practice conditions in the design of
therapeutic interventions for individuals using orthoses or
prostheses.
5. Appropriately use augmented feedback in therapeutic sit­
uations with individuals using orthoses or prostheses.
6. Describe the role of mental practice and imagery on skill
acquisition for individuals using orthoses or prostheses.
WHY THINK ABOUT MOTOR CONTROL,
MOTOR LEARNING, OR NEUROPLASTCITY?
Physical therapists and colleagues in rehabilitation help indi­
viduals with movement dysfunction improve or adapt their
ways of moving so that they are safe, efficient, and satisfied
with their level of function in the activities they consider
important for their quality of life.1 Many different impair­
ments, across any of the physiological structures and systems
of the body, might lead to ineffective or abnormal patterns of
movement and interfere with an individual's ability to carry
out activities and participate effectively in their family and
social roles.2,3
Several underlying principles influence current thinking
about how people move.4 The first is that movement is goal
directed. Individuals move in order to accomplish a task or
activity that they want to do, during self-care or other activi­
ties of daily living (ADLs), as part of their work role, or during
leisure activities.5 The second is that there are many differ­
ent ways to accomplish any task: the central nervous system
(CNS) organizes muscles and bodies using available physio­
logical resources in the context of the environment to accom­
plish any given task; there is no single “best” way of moving.6–8
The  third is that each person develops preferential ways of
­moving: although there are many possible movement strat­
egies available, people tend to move in ways that are most
efficient for their own, individual physical characteristics.9
Preferential movement patterns, however, are not always opti­
mal ways of moving. Repetitive motion injuries, for example,
may be the result of preferential movement patterns that are
not biomechanically effective, stressing tissues until inflam­
mation or permanent deformation occurs.10 Finally, emerg­
ing evidence suggests that appropriate interventions have the
potential to drive neural plasticity and enhance recovery fol­
lowing insult to the CNS.
When there are impairments of musculoskeletal, neuro­
muscular, or cardiopulmonary systems, the resources that
an individual can bring to movement may be altered, lim­
ited, or constrained.11 Because movement is goal directed,
an individual with impairments will find a way to accom­
plish movement goals that “work,” often using a less effective
or abnormal movement strategy. These altered strategies are
recognized clinically as movement dysfunction.12 The use
of ineffective or abnormal movement patterns, over time,
can lead to inflammation, tissue remodeling, or even defor­
mity.13 In an individual recovering from stroke who is walk­
ing, for example, an “abnormal” extensor synergy of the
lower extremity may provide stance phase stability but will
impair swing limb advancement, leading to a compensatory
circumduction or vaulting step.14 Abnormal tone may con­
tribute to habitual plantar flexion and eventually an equinus
deformity.15 Someone with a painful knee or back will alter
the way he or she uses those joints, as well as the limbs or
trunk, when walking and moving between sitting and stand­
ing.16–20 Over time, the individual may develop secondary
musculoskeletal problems at distal or proximal joints or
become physically deconditioned, compounding his or her
movement dysfunction.21,22 An individual with pain, short­
ness of breath, or a sense of fatigue (whether due to disease
or deconditioning) may choose to be less active to “con­
serve” energy and, as a result, become even more decondi­
tioned, develop soft tissue tightness that impairs flexibility,
and lose muscle mass that limits functional strength.23–27
Individuals who are concerned about pain, falling, or injury

Chapter 3  Motor Control, Motor Learning, and Neural Plasticity in Orthotic and Prosthetic Rehabilitation
39
may also limit physical ­activity and have similar decrement
in physiological capacity and resources.28–30
Physical and occupational therapists use various types of
therapeutic exercise (e.g., strengthening, endurance programs,
flexibility, balance activities), as well as functional training
(often with assistive devices or ambulatory aids, orthoses,
and prostheses), in order to minimize movement dysfunction
and to remediate or accommodate the underlying impair­
ments.31 To be effective in these interventions, rehabilitation
professionals must understand the principles of exercise and
the effect that exercise has on the human body.32–34 They must
know both the purpose of an orthosis, prosthesis, or assistive
device and how the design of the device will enhance or con­
strain movement and function.35,36 If the goal of rehabilita­
tion professionals is to help those with movement dysfunction
learn more effective ways to accomplish what is important to
them, they must also be aware of the process of learning, both
on a cognitive and a motor level, and integrate this under­
standing into the interventions they plan and implement.37
This chapter provides an overview of recent thought on
motor control, using a dynamic systems perspective. The
chapter also reviews the tenets of motor learning and con­
siders practice, augmented feedback, and mental imagery
as tools to assist development of new or adapted movement
skills. The chapter also consider how physical therapy inter­
vention founded on knowledge of motor control and motor
learning can augment neural plasticity and recovery after
brain injury. The case studies at the end of the chapter are
designed to help readers integrate growing understanding of
the principles of motor control and of motor learning into the
planning of interventions for movement dysfunction.
THEORIES OF MOTOR CONTROL
Human movement has traditionally been examined from two
distinct fields of study: a neurophysiological control approach
and a motor behavioral approach.4,38–41 The traditional neu­
rophysiological approach explained movement within a hier­
archical system of control on the basis of the development of
neural mechanisms within the central and peripheral nervous
systems and the interaction of sensory and motor systems. The
motor behavioral approach examined movement performance
from the perspectives largely from the field of psychology. Only
in the past few decades have the two fields of study interfaced
to bring about newer theories regarding human movement that
more fully explain human movement and performance.4,41–43
Recently, there has been an increasing emphasis on the use of
therapeutic intervention as a means of driving neural plasticity
as a mechanism of recovery following brain injury.44–46
Dynamic Systems Perspectives
Rehabilitation professionals think about the human body as
a complex biological system with many interacting elements
and subsystems (Figure  3-1). These components have an
infinite number of ways to work together in accomplishing
a goal-directed motor act.47–49 Because the human body is a
dynamic, adaptive, and inherently complex set of subsystems,
motor behaviors and ways of moving become more efficient
with practice and experience: motor control systems can con­
sistently generate simple and well-organized movement from
a complex array of movement possibilities.50,51 The dynamic
systems perspective of motor control is founded on under­
standing of behaviors that physical systems of various types
have in common: the ability to change over time, the abil­
ity to be adaptive yet have preference for habitual tenden­
cies, and the context of interaction with the environment
in which movement occurs.43,52–54 In the human movement
system, there is great “motor abundance”; each person has a
wide variety of ways to accomplish an intended movement
goal (i.e., solve a functional movement problem) in whatever
environmental conditions or circumstances that function
occurs.55,56
According to Bernstein's model of motor control, individ­
uals have the capacity “to make a choice within a multitude
of accessible trajectories . . . of a most appropriate trajectory.”57
Dynamic systems theory suggests that there are both oppor­
tunities and challenges presented by interaction of the envi­
ronment and the individual's will to move.57 Unlike systems
that are purely physical, the human biological system is a
smart, special-purpose machine able to instantaneously and
efficiently work to meet the many parallel and serial func­
tional demands.58–60 In addition, biological systems such as
the human body are self-organizing59,61; the mutually depen­
dent and complex processes among the body's subsystems
allow this wonderfully dynamic structure to enact efficient
functional movement patterns. Even though it is an inher­
ently multidimensional biological system, the human body
prefers to be in a state of relative equilibrium.62,63 This is likely
to be the underlying reason that the gait cycle at self-selected
(comfortable) walking speed tends to center around one cycle
per second, and that most individuals transition from walk
to run, as gait speed increases, at nearly the same velocity.64
The human body, as a smart and dynamic biological system,
is also intentional; there is a purposeful, goal-directed, and
task-oriented nature in most motor behaviors.65 The dynamic
systems model defines an intention as a purposeful or desired
act that influences (attracts) the human system to organize
motor behavior toward the desired outcome, in the context
of the environment in which the movement is occurring.66
The organism and the environment are interdependent; each
is defined with respect to the other.58,65,66 Although the char­
acteristics of the physical environment are the focus on many
studies of goal-directed movement, the social-emotional envi­
ronment can also influence the emergence of goal-directed
movement.67 The combination of resources available to the
organism-environment interaction, in conjunction with the
individual's intention, shapes (constrains) how task-oriented
motor behavior is organized.
Motor control has been defined by Shumway-Cook and
Woollacott as “the ability to regulate or direct the mecha­
nisms essential to movement.”39 The interactive systems
that provide resources that an individual uses to initiate and
regulate goal-directed movement include the neurological,

40
Section I  Building Baseline Knowledge
musculoskeletal, sensory/perceptual, cardiorespiratory, and
cardiopulmonary, and the cognitive, learning, and memory
systems. Human movement, or motor control, is a product of
the interaction of the individual (with all of his or her subsys­
tems), the characteristics of the environment, and the nature
of the specific task or goal that the individual is involved in
(Figure 3-2). Movement, then, is goal directed and purpose­
ful; it makes use of the innate and learned resources avail­
able to the individual and is subject to the influences of the
environment in which it is performed. By considering each of
these essential contributors to functional movement, rehabili­
tation professionals can assess potential sources of movement
dysfunction, explore alternative movement strategies, and
adapt or alter the task or environment to improve ­movement
outcomes.68,69
Resources of the Individual
The first component to consider in this model of motor con­
trol is the individual, with his or her ability to think and rea­
son, to sense and perceive, and to actively respond or initiate
DATA
COLLECTION
Sensory
INTERPRETATION
Perception
INTEGRATION
COORDINATION
MEMORY
MOTIVATION
LEARNING
COGNITIVE
CONSCIOUSNESS
HOMEOSTATIC
VEGETATIVE
ENERGY
Cardiopulmonary
Cardiovascular
COMMUNICATION
Language
MOTOR PLANNING
MOTOR CONTROL
EFFECTOR
Neuromuscular
Musculoskeletal
GOAL-DIRECTED
MOVEMENT
FIGURE 3-1  The interactive physiological systems of the body that contribute to an individual's
ability to carry out during goal-directed (functional) movement. Sensory and perceptual systems
contribute by monitoring the environment as well as the position and condition of the body during
movement. Integrative, coordination, cognitive, memory, motivational, and planning systems work
together to determine how a goal-directed task might be best implemented, corrected, or adapted
for success. Homeostatic, vegetative, and energy systems anticipate physiological demand and insure
that oxygen and glucose supplies are sufficient to meet task demands. The neuromuscular system fine
tunes postural control, tone, and recruitment so that the musculoskeletal system can be used effec­
tively to accomplish the movement goal. Continuous communication and interaction among physi­
ological systems occurs before, during, and in response to movement so that both feed-forward and
feedback can instantaneously influence task performance.