A Pilot Clinical Trial to Assess the Effect of Transfemoral Socket Design on Hip Muscle Function
Phase: NA
Conditions: Amputation
Sponsor: University of Illinois at Chicago

 
 
 
Title: Transfemoral Socket Design and Muscle Function 
 
 
NCT #: 04212299 
 
 
Document Date: August 8, 2019 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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Hip Muscle Function in Lower Limb Prosthesis Users 
Principal Investigator: 
Andrew Sawers, PhD 
Department of Kinesiology and Nutrition, College of Applied Health Sciences 
Department of Bioengineering, College of Engineering 
1919 W. Taylor Street 
Applied Health Science Building Room 502 
Phone: 312-996-1427 
 
Co-Investigators: 
Stefania Fatone PhD 
Northwestern University 
Department of Physical Medicine and Rehabilitation 
680 N Lake Shore Drive 
Chicago IL, 60611 
Phone: 312-503-5717 
 
Sponsor: Department of Defense 
 
Version: 1.1 
 
 
Date: July 22, 2019 
 
 
 

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TABLE OF CONTENTS 
Page 
Table of Contents ............................................................................................................. 3 
List of Abbreviations ......................................................................................................... 4 
1.0 Project Summary/Abstract ....................................................................................... 5 
2.0 Background/Scientific Rationale ............................................................................... 6 
3.0 Objectives/Aims ...................................................................................................... 7 
4.0 Eligibility .................................................................................................................. 7 
4.1 Inclusion Criteria .............................................................................................. 8 
4.2 Exclusion Criteria ............................................................................................. 8 
4.3 Excluded or Vulnerable Populations .............................................................. 8 
5.0 Subject Enrollment ................................................................................................. 8 
6.0 Study Design and Procedures .............................................................................. 9 
7.0 Expected Risks/Benefits ...................................................................................... 11 
8.0 Data Collection and Management Procedures .................................................. 13 
9.0 Data Analysis ........................................................................................................ 13 
10.0 Quality Control and Quality Assurance .............................................................. 14 
11.0 Data and Safety Monitoring ................................................................................. 14 
12.0 Statistical Considerations ................................................................................... 14 
13.0 Regulatory Requirements .................................................................................... 15 
13.1 
Informed Consent ........................................................................................ 15 
13.2 
Subject Confidentiality ................................................................................. 16 
13.3 
Unanticipated Problems ............................................................................... 16 
14.0 References ............................................................................................................ 18 
Appendices ..................................................................................................................... 20 
 

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LIST OF ABBREVIATIONS  
 
COI 
 
 
Conflict of Interest 
 
EMG  
 
Electromyography 
 
IRB 
 
 
Institutional Review Board 
 
PI 
 
 
Principal Investigator 
 
PLUS-M 
 
Prosthetic Limb Users Survey – Mobility  
 
PROMIS 
 
Patient-Reported Outcomes Measurement Information System 
 
REDCap 
 
Research Electronic Data Capture 
 
SENIAM 
 
Surface Electromyography for the Non-Invasive Assessment of Muscles  

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1.0 
Project Summary/Abstract 
The objective of this research project is to evaluate hip muscle function among lower limb 
prosthesis users, its contribution to balance and mobility, and the effect of prosthetic socket 
design on amputated limb hip muscle strength and endurance. Traditional socket designs can 
provide pelvic support that interferes with hip motion. They may also reduce the effort required 
from amputated limb hip muscles to stabilize the hip and amputated limb, risking further loss of 
muscle mass and strength beyond that due to amputation. Long-standing use of sockets with 
pelvic support may therefore intensify amputated limb muscle loss and weakness, leading to 
challenges with walking and balance, increasing the effort required to walk, and contributing to 
degenerative changes in the hips and knees. 

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2.0 
Background/Scientific Rationale  
Residual limb hip muscle weakness is a pronounced, consequential, and modifiable deficit 
among prosthesis users that is not adequately understood. After amputation residual limb hip 
muscles undergo structural changes, such as atrophy1,2,3 and fatty infiltration4,3, causing 
pronounced muscle weakness2,5-7. These changes are not observed with the same frequency or 
magnitude in the intact leg5, suggesting they are due to amputation13 and/or socket design9 
rather than general deconditioning5. Assessments of residual limb strength have, to date, 
however been limited to non-fatiguing conditions, and measures of maximum voluntary 
strength2,5,6. Important functional aspects of strength including the rate of force development, 
which is essential to balance10-11, and muscular endurance, which is crucial to mobility12,31 and 
strenuous tasks like load carriage12, have been overlooked. Additionally, a number of major 
residual limb hip muscles and relevant covariates (e.g., etiology) remain untested. As a result, 
we do not have a full understanding of the force generating capacity of residual limb hip 
muscles in transfemoral prosthesis users that is required to assess the effect of socket design 
on residual limb hip muscle function. To address this gap a comprehensive evaluation of 
residual limb hip muscle strength and endurance is needed. 
 
Preliminary evidence suggests residual limb hip muscle weakness is a consequential deficit 
among transfemoral prosthesis users. Muscle weakness has been associated with gait 
abnormalities1,13, secondary degenerative disorders (e.g., joint degeneration)14, increased 
metabolic cost of gait15,16, as well as reduced mobility17,18 and balance confidence19. Causal 
links however between residual limb hip muscle function and balance or mobility remain poorly 
understood among transfemoral prosthesis users21. Preliminary statistical modeling of causal 
relationships between residual limb hip muscle function and walking and balance performance 
is needed to address this gap.  
 
Fortunately, residual limb hip muscle weakness appears to be a modifiable, and thus a 
treatable deficit in transfemoral prosthesis users. Gains in residual limb hip muscle strength 
have been observed in lower limb prosthesis users after only moderate strength training (8-12 
weeks; 2/week)15,19,21. Whether socket design has a similar modifying effect on residual limb hip 
muscle strength is unknown, but presents an appealing opportunity. The prospect of increasing 
residual limb hip muscle strength and endurance simply by walking with a different socket 
design is attractive because it could be accomplished in a patient’s own home, community, and 
workplace, without additional equipment (i.e., environment and activity specific strength 
training). Our prior results and anecdotal reports support a study to quantify changes in residual 
limb hip muscle function in lower limb prosthesis users wearing different sockets. 
 
 
 
 
 
 

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3.0 
Objectives/Aims 
 
The objective of this study is to assess residual limb hip muscle function in lower limb prosthesis 
users, understand its role in balance and mobility, and the effect of socket design on residual 
limb hip muscle function. Our central hypothesis is that the residual limb is weaker than the 
intact limb as well as controls, and that socket design alters hip muscle function. To address this 
objective and central hypothesis, we will assess the following specific aims: 
 
Aim 1: Evaluate hip muscle function and its contribution to balance and mobility among 
unilateral lower limb prosthesis users. We hypothesize that: i) the strength and endurance of hip 
muscles on the residual limb will be lower than on the intact limb, and of age- and sex-matched 
able-bodied persons, and ii) muscular strength and endurance will not differ between the intact 
limb and age- and sex-matched able-bodied persons. To test these hypotheses hip muscle 
strength and endurance will be measured using a motor-driven dynamometer. Lower peak 
torque and rates of torque development will be taken as evidence of reduced strength, while a 
larger decrease in average work at the end of an isokinetic fatigue protocol will be taken as 
evidence of reduced endurance. Secondarily, we will also collect balance and mobility outcomes 
data (e.g., Four Square Step Test, PLUS-M, step counts, and fall history), and use regression 
methods to explore the contributions of hip muscle strength and endurance to balance and 
mobility in lower limb prosthesis users. 
 
Aim 2: Test whether socket design alters hip muscle function among lower limb prosthesis 
users. We hypothesize that walking with different socket designs will: i) require different residual 
limb hip muscle activity, as evidenced by greater peak muscle activity, as well as altered onset 
and offset times, and ii) result in short- and long-term gains in residual limb hip muscle strength 
and endurance, as evidenced by an increase in average peak torque, rate of torque 
development, and resistance to fatigue. To test these hypotheses electromyographic signals will 
be recorded from hip muscles on the residual limb of unilateral lower limb prosthesis users 
walking at a range of speeds. Hip muscle strength and endurance will be measured using a 
motor-driven dynamometer. Assessments will be made at baseline in established wearers of an 
ischial containment socket, and then again at eight and 42-weeks after being fit with a sub-
ischial socket. Step count activity data will be collected to determine the extent to which gains in 
residual limb hip muscle strength and endurance are due to changes in hip muscle activation 
versus an increase in physical activity. 
 
 
4.0 
Eligibility 
 
The target population for the proposed study is adult unilateral lower limb prosthesis users 
whose amputation is due to traumatic, dysvascular, or oncologic reasons. We will not exclude 
participants based on age, race, sex, or ethnicity. In an effort to recruit and include under-
represented minorities will we monitor participant demographics during the study and adjust our 
efforts as necessary to improve the inclusion of under-represented groups.  
 

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We will recruit lower limb prosthesis users in Chicago from Scheck and Siress Prosthetics and 
Orthotics. Scheck and Siress have over a dozen clinics in the Chicagoland area. Their offices 
regularly treat more than 2000 lower limb prosthesis users a year. Clinicians at Scheck and 
Siress will only participate in passive recruitment, sharing information about current research 
participation opportunities with patients. We may recruit from other clinics in the Chicagoland 
area if recruitment proves to be challenging. 
 
Participant eligibility will be evaluated and determined by the investigators or research staff 
using specific inclusion and exclusion criteria via in-person or phone interviews. In person 
interview will occur in any of three locations: 
 
1. Disability, Health, and Social Policy Building, Room 198 1640 W. Roosevelt Road, Chicago 
IL, 60608 
2. Applied Health Science Building, 1919 W. Taylor Street, 646; Chicago, IL 60612 
 
4.1 Inclusion Criteria 
Inclusion criteria for lower limb prosthesis users will be: 1) worn prosthesis for ≥ 2 years, 2) able 
to walk short distances (10 meters), 3) ability to read, write, and speak English, and for Aim 2 
only, ≥ 2 years using a liner-based suspension, and a residual limb length ≥ 5”. Inclusion criteria 
for unimpaired controls will be: 1) ability to read, write, and speak English, 2) between the ages 
of 18-85 years of age, and 3) able to walk short distances (10 meters). 
 
4.2 Exclusion Criteria 
Exclusion criteria will be: 1) amputation of a second leg, 2) contralateral complications (e.g., hip 
replacement), or 3) other major neuromusculoskeletal or cardiovascular conditions (e.g., heart 
failure). Age- and sex-matched able-bodied persons will be recruited from the community for 
Aim 1 with non-amputation related criteria applicable (e.g., major neuromusculoskeletal or 
cardiovascular conditions). 
 
4.3 Excluded or Vulnerable Populations 
Subjects younger than 18 and older than 85 years of age will be excluded, as their inclusion 
would introduce confounding factors of sensorimotor changes due to motor development and 
aging.  
 
Subjects for whom English is a second language will also be excluded because there are 
extensive verbal instructions that must be provided to the participants. Translation services are 
not readily available to assist laboratory personnel. Participants will also be expected to provide 
information via self-report survey instruments that have not been translated and/or validated in 
other languages. 
 
Individuals with bilateral lower limb loss and any upper extremity limb loss will be excluded, as 
their biomechanics are not comparable to individuals with unilateral lower limb loss.  
 
5.0 
Subject Enrollment 

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Lower limb prosthesis users will be recruited from prosthetics clinics in Chicago via flyers or 
information about the study provided to them by clinic staff during clinic visits. Age- and sex-
matched able-bodied persons will be recruited from the community via flyers placed on the UIC 
campus. 
 
To minimize coercion or undue influence over the patient population of interest, lower limb 
prosthesis users, it will be communicated to them that their clinical care does not depend in any 
way on whether they elect to participate or not in this research study. 
 
If an individual shows interest in participation in the study, we will obtain general health 
information from them to confirm that they are eligible for study participation. General health 
information will include age, weight, and self-reported medical history, including if they have any 
vision impairments, balance impairments, cognitive impairments, progressive neurological 
conditions, or any other major motor or sensory dysfunction or medical condition. This screening 
process could talk place via a telephone interview or in person. Regardless of the method, 
screening will be done in a private room to protect participant’s confidentiality. After participants 
review and sign consent forms on the day of the assessment, we will obtain more detailed 
health information during an interview using several surveys and questionnaires. 
 
Any data that is collected from participants who are not eligible or interested in participating in 
the study will be deleted from our records. Electronic data will be permanently erased from the 
stand alone PC on which it is collected. Any hard copies will be shredded.  
 
6.0 
Study Design and Procedures 
 
Consented individuals will participate in 1 or 3 test sessions. Each session will require 
approximately 3 hour. For Aim 1, we will conduct a cross-sectional study to evaluate residual 
and intact limb hip muscle function in lower limb prosthesis users compared to able-bodied 
persons. All participants will be administered characterization measures, balance and mobility 
tests, as well as a series of procedures to evaluate hip muscle strength, endurance, and 
coordination. This will require a single 3-hour test session. Able-bodied controls and lower limb 
prosthesis users will perform the same activities in Aim 1. 
 
For Aim 2, we will conduct a pilot within-subjects study to assess if walking with a different 
socket alters residual limb hip muscle function. In Aim 2, a sub-set of lower limb prosthesis 
users from Aim 1 will walk with a different socket. These participants will be selected on the 
basis of meeting the inclusion and exclusion criteria specified above for Aim 2. The same 
measures, tests, and procedures from Aim 1 will be administered in Aim 2 at two time points, 
eight and 42-weeks after baseline testing. Outcomes at these two time points will be compared 
to baseline (Aim 1) to evaluate differences in hip muscle function associated with walking in a 
different socket. Three total test visits will be required of participants in Aim 2.  
 
The tasks listed below will be performed at each visit.  
 

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Characterization Measures: Sociodemographic, health, falls history (all subjects), and 
prosthetic-related information (prosthesis users only) will be collected using psychometrically 
robust self-report outcomes to characterize study participants. This will include age, general 
health (PROMIS 29), residual limb length, cause and time since amputation, mobility (Prosthetic 
Limb Users Survey-Mobility), socket comfort (Socket Comfort Score), and balance confidence 
(Activities-specific Balance Confidence Scale). Falls history will be obtained by asking 
participants “in the past year have you inadvertently lost your balance and landed on the ground 
or lower level?”. Amputation surgical techniques (e.g., muscle fixation) may vary across 
participants, and confound assessments of residual limb hip muscle function. In an effort to 
obtain this data we will create a permission form to be signed by the participant and sent, along 
with a short survey, to their surgeon requesting basic information about the amputation 
procedure (e.g., myoplasty versus myodesis). 
 
Hip Muscle Strength and Endurance: Hip flexor, extensor, adductor and abductor muscle 
strength and endurance will be measured in lower limb prosthesis users and able-bodied 
persons using a motor-driven isokinetic dynamometer (Biodex System 4 Pro, NY). Participants 
will be secured in standardized positions that maximize stability and minimize compensatory 
movements, providing the most valid and reliable measurements (i.e., side-lying for 
adduction/abduction, supine for flexion/extension). The axis of the dynamometer will be aligned 
to the hip joint, and the arm of the dynamometer will be adjusted to the greatest length that is 
comfortable and allows for firm attachment of custom-made shells to the test limb. The mass of 
the tested limb will be measured in a relaxed position by the dynamometer to correct for gravity. 
Three submaximal repetitions will be performed in each test position to familiarize participants 
with the test procedure. Fifteen consecutive maximal voluntary isometric contractions will then 
be performed in each test position. Isometric concentric testing was chosen because of its 
validity and reliability, and its relationship to walking capacity. Mandatory 5-minute rest periods 
will be enforced between testing in each position. Muscular strength will be assessed via 
average peak torque (i.e., highest torque) and rate of torque development (i.e., slope of the 
torque/time curve from onset to peak) across the first three repetitions. Torque onset will be 
defined as the instant torque exceeds 2% of peak torque. Lower values will be taken as 
evidence of reduced muscular strength. Muscular endurance will be assessed via a fatigue 
index, calculated as a percentage of the difference between total work performed during the first 
and last 5 repetitions divided by total work over the first 5 repetitions. A higher fatigue index will 
be taken as evidence of reduced muscular endurance. All values will be normalized to body 
weight, and the order of test positions will be randomized.  
 
Hip Muscle Activity: Surface electromyography (EMG) data will be recorded at 1200Hz (Motion 
Labs, Baton Rouge, LA) from six muscles (adductor magnus, rectus femoris, tensor fascia latae, 
gluteus medius, biceps femoris long head, and gluteus maximus) on the residual limb of 
prosthesis users walking at preferred, slow (-25%), and fast (-25%) speeds on a force-sensing 
treadmill (Treadmetrix, Salt Lake City, UT). Speeds will be maintained across test sessions 
(baseline, 8-, and 42-weeks). Ground reaction forces will be recorded simultaneously at 1200Hz 
to identify gait cycle events. Neonatal electrodes, placed according to the Surface 
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used to accommodate the collection of in-socket EMG signals. Raw EMG signals will be: i) 
band-passed filtered (10-500Hz) to remove non-muscle frequencies, ii) high-pass filtered (50Hz) 
to remove motion artifact, iii) notch-filtered (59.5-60.5Hz) to remove ambient power line noise, 
iv) amplitude normalized to the peak of the subject’s ensemble average during fast walking on 
visit 1, and v) time normalized to 100% gait cycle (i.e., initial contact to initial contact). Activity of 
residual limb hip muscles will be characterized by onset and offset times, as well as the 
integrated area and peak activity. Onset and offset times will be identified from processed EMG 
signals using a Teager-Kaiser energy operator signal-conditioning algorithm, and referenced to 
initial contact. This procedure detects EMG burst boundaries with greater accuracy than other 
methods. The integrated area and peak activity of EMG bursts will be calculated by applying 
trapezoidal integration and thresholding techniques to linear EMG envelopes generated from full 
wave rectification and low-pass filtering (10Hz cut-off) of processed EMG signals. Muscle 
activity metrics will be averaged over a minimum of 10 strides per participant. EMG processing 
and analyses will be performed using custom Matlab™ (MathWorks Inc., Natick, MA) routines.  
 
Balance and Mobility Tests: To assess balance and mobility, prosthesis users will be 
administered six standardized and psychometrically robust performance-based clinical tests: 
Four Square Step Test (dynamic balance), One Leg Stance Test (static balance), 10-Meter 
Walk Test (walking speed), 2-Minute Walk Test (walking endurance), 5-Times Sit to Stand 
(muscular strength), 30-second Sit to Stand (muscular endurance), or Functional Reach Test 
(postural balance). Tests will be administered in a randomized order, and according to the 
developer’s instructions. Mandatory 5-minute rest periods will be enforced between each test.  
 
Step Count Activity: To assess physical activity, lower limb prosthesis users will wear a 
StepWatch4 activity monitor (Modus Health, Edmonds, WA) for three 2-week periods. First, 
immediately after baseline testing, and then for two weeks prior to both the eight and 42-week 
tests. StepWatch has a step count accuracy above 98%. Activity bouts, or periods of time in 
which steps occur in successive 10-second intervals, will be derived from step count data. 
Physical activity will be quantified by its volume (i.e., mean number of steps per day), frequency 
(i.e., mean number of activity bouts per day), and duration (i.e., mean length of activity bouts per 
day). Higher values will be taken as evidence of greater physical activity.  
 
Video images: During the study, video records will be collected of the assessments. Video files 
will be stored on a computer as a visual record of the events that occur during the trials and may 
be kept indefinitely for analysis by the researchers in a secured and locked location. The video 
will only be accessible by research personnel, unless the participant gives permission otherwise 
on the consent form. 
 
7.0 
Expected Risks/Benefits 
 
Foreseeable, potential risks for prosthesis users and able-bodied controls participating in this 
study include: a) fatigue resulting from long periods of standing or walking, b) injury from 
mechanical failure of the equipment (e.g., treadmill, motorized dynamometer), c) falling during 
administration of the study protocol, d) electrical shock associated with recordings of 

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electromyograms (EMG), e) irritation to the skin from medical grade tape used to attach sensors 
to the body, or f) embarrassment. The risk associated with these events is expected to be low. 
We have attempted to reduce known potential risks. We do not know of alternative procedures 
that can reduce these risks and provide the same information. The safety precautions 
associated with the potential risks are as follows: 
 
a) Loss of balance and falls: All study personnel will undergo falls training led by the PI. 
This training will familiarize them with appropriate spotting techniques to catch a 
participant if they begin to fall. 
 
b) Fatigue: The test sessions may last up 3 hours, however, only 90 minutes are dedicated 
to study procedures. This duration may nonetheless be fatiguing to some participants. 
The majority of the time is devoted to participant preparation and instrumentation, a 
large part of which is done while the participant is either sitting or lying down. We will 
enforce sitting breaks of at least 5 minutes every 20 minutes of experimentation. The 
breaks will only end with the participant’s consent and participants will be continually 
monitored during testing by the evaluator and trained assistants for fatigue and 
instability. 
 
c) Mechanical injury: The treadmill and motorized dynamometer are physically limited by 
the motor torque and cannot deliver excessively large, injury-causing perturbations. 
They are equipped with limit switches that shut down power if they reach near the end 
range of their capabilities. Software limits further limit uncontrollable movements of the 
treadmill and dynamometer. There is an emergency stop button next to the experimenter 
and on the treadmill as well as the dynamometer for participants. Additionally, all 
equipment will be inspected for safety as part of the set up routine for each data 
collection session. 
 
d) Electrical shock: The risk of electrical shock is extremely low and limited to non-injurious 
levels of current and voltage. Our electromyography equipment is a telemetered unit 
powered by a standard 9-volt battery. Therefore if a malfunction were to occur, any 
electrical shock produced would be extremely mild. Our equipment is available 
commercially (Motion Lab Systems) and no participants have experienced any electric 
shock or tingling sensations due to current flow. 
 
e) Skin irritation: Some participants are sensitive to the adhesive used in medical grade 
tape. This can result in temporary irritation such as redness or itchiness in areas where 
tape has contacted the skin. We will ask participants if they have known tape sensitivity 
before the experiment begins. The supply of tapes and adhesives we use are 
hypoallergenic medical grade that are commonly used in hospitals. In the PI’s 
experience in and around the testing of hundreds of human participants with similar 
supplies, only one case of tape allergy has occurred. This one incident left no permanent 
injury to the participant. 
 
f) Discomfort/embarrassment: To reduce potential discomfort or embarrassment in 
answering health related questions all questionnaires will be completed in a private 
room. If participants do not want to answer particular questions they do not have to. To 
reduce embarrassment of being videotaped all recordings will be taken from behind. 
Faces will not be recorded. Any identifiable marks will be blurred if videos are ever used 

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in a presentation. Video recording is optional. To minimize any potential embarrassment 
due to loss of confidentiality all records of participation that included information about 
participants will be coded. Names and unique subject IDs do not appear on the same 
documents. The data from this study cannot be traced directly back to participants. 
Additionally, all documents from this research will be kept in a locked file cabinet by the 
study team. We are the only ones with access to these documents. 
 
We do not anticipate that participants will receive any direct benefit from participating in the 
study. The study is not being conducted to improve their health condition. It is hoped that 
knowledge gained from this research may benefit other lower limb prosthesis users in the future 
by providing an approach to increase and/or prevent the loss of residual limb hip muscle 
strength.  
 
8.0 
Data Collection and Management Procedures 
 
Muscle activity data, as well as isometric strength data will be collected on a stand-alone 
desktop computer and stored electronically on that PC as well as a backup hard drive. Access 
to this data on the PC and the external hard drive will be protected via a password that only the 
PI and his students will have access to. Both the PC and external hard drive are located in our 
lab, which is locked.  
 
Data collected using performance-based balance and mobility tests will be recorded on paper 
data collection forms. Collected data will be stored in subject-specific folders, located in a locked 
filing cabinet (separate from consent form cabinet). Keys for this cabinet will be kept in a 
lockbox with a 4-digit passcode that only the PI and his students will know. 
 
Survey responses collected during experiments will be entered and stored in a secured 
REDCap database. REDCap will only be assessable to study personnel including the PI, Co-I, 
and other research staff via password protection. This ensures that de-identified data will be 
secure yet available to all investigators involved in the study. 
 
A master code sheet linking subject names to study ID # will be kept in the PI’s or site PI’s 
offices in a locked cabinet. This location is separate from where the data is collected and stored. 
Only the PI or site PI will have access to this master list. The master list is necessary for the 
multiple visit portion of the study. When subjects return for their 2nd  and 3rd visit we will have to 
assign them the same ID# as in previous visits.  
 
9.0 
Data Analysis 
Data will initially be processed in the lab on the stand-alone PC and then backed up to the 
external hard drive. The PI and his students will perform additional analyses on computers in 
their office space that are password protected. Data analysis may include the use of such 
computer programs as Matlab, SPSS, and Excel. 

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At no point will any data on the lab stand-alone PC, the PI’s computer, or those of his students 
contain any private health information or data that could be linked to specific subjects via 
personnel identifiers. 
 
10.0 Quality Control and Quality Assurance 
After every assessment, the PI and/or one of his students will review that all inclusion and 
exclusion criteria for screening were met. They will also review that all data was collected in a 
manner that is consistent with what is outlined in the protocol and consent form. Any departure 
from the protocol or failure to meet inclusion/exclusion criteria will be reported to the IRB and 
the data will be deleted.  
Collected data will be regularly entered into entered into REDCap and reviewed by the site PIs. 
This will provide regular review of the data quality.  
 
11.0 Data and Safety Monitoring 
To ensure the safety of subjects and keep personal information private the following 
procedures will be followed. In the event of an injury or adverse event we will call 911 if 
necessary, and report any adverse event to the IRB in a timely manner (within 3 business 
days). Subjects requesting medical treatment will be directed to the appropriate source of 
treatment. These adverse events could be physical injury or a breach in confidentiality. We 
will maintain a safety log of adverse events (falls, skin irritation, breach of confidentiality etc) 
for each session that is kept in a locked drawer in the lab. A brief summary of the 
experiment, whether any adverse events occurred, when they were reported, and what 
actions will be taken to prevent them in the future will be recorded after. An example of this 
log is attached to this application (“Research Safety Log”). 
 
12.0 Statistical Considerations 
Descriptive statistics: Measures of central tendency and variation will be used to describe 
participant characteristics, and all study variables (e.g., balance and mobility tests, muscle 
strength). Normality, homogeneity of variance, and multicollinearity will be evaluated using the 
Shapiro-Wilk test, Levene’s test, and, Pearson’s r (r<.90) respectively. If assumptions are met 
data will be analyzed with parametric tests, otherwise non-parametric tests will be used. 
Statistical analyses will be performed using SPSS 25 (Chicago, IL). 
 
 
Aim 1: A 2-way mixed-MANCOVA (multiple analysis of covariance), or non-parametric 
equivalent, will be used to test for statistically significant differences in strength and endurance 
between legs (prosthetic, intact, and control) as well as across muscle groups while controlling 
for potential covariates (e.g., residual limb length, etiology). Multiple linear regression will be 
used to determine how much variation (i.e., difference) in balance and mobility outcomes (e.g., 
Four Square Step Test; physical activity) among transfemoral prosthesis users can be explained 
by differences in hip muscle strength and endurance.  
 
Aim 2: As a pilot study, descriptive analyses including measures of central tendency (mean) and 
dispersion (95% confidence intervals), along with effect sizes (e.g., Cohen’s d, common 

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language effect size), will be used to evaluate changes in residual limb hip muscle activity, 
strength, between test sessions while controlling for covariates. Correlation analyses will be 
used to determine if any observed changes in hip muscle strength can be attributed to changes 
in hip muscle activity (i.e., EMG) or physical activity (i.e., step count). 
 
Power Analysis: Choosing a power of 0.80 and a type I error rate (a) of 0.05, pilot data from 
lower prosthesis users (n=2) and able-bodied persons (n=2) estimate that a sample of 20 
people per group will be sufficient to identify differences (p<0.05) in hip muscle strength and 
endurance between the residual limb, intact limb, and able-bodied persons using a mixed 
analysis of variance (ANOVA) (Aim 1). As a pilot study, enrollment in Aim 2 will be limited to 10 
unilateral lower limb prosthesis users. 
 
13.0 Regulatory Requirements 
13.1 Informed Consent  
When participants arrive in the lab, they will meet study staff and review the informed consent 
form with him and/or other research personnel. The PI and/or other research personnel will 
review all of the key points in each section and allow the participant to read the consent form 
and ask any questions. Participants will participate in the experiment only after granting full 
informed consent. Consent capacity will be assessed by a discussion of the proposed research 
project. During the consent process, a series of questions can be asked to assess 
understanding of key issues. Such questions will relate to the purpose of the research and the 
foreseeable risks and anticipated benefits of study participation or understanding of the 
voluntary nature of research and the elements of consent, including the right to be informed 
about appropriate alternative procedures or courses of treatment that may be available. 
 
All participants will be told that if they choose not to consent, at this time or anytime during the 
study, they will be allowed to stop and leave. They will also be told that by consenting at the 
start of the study they are not required to finish the study. They are free to end their participation 
at any time without having to give an explanation. They can then decide whether they want their 
data deleted or if it can still be included in our analyses. This will be documented in a revocation 
form. Participants will also be told that will still be compensated for their time spent in the study 
prior to terminating their participation. 
 
During the consent process all participants will be given the opportunity to consent to having 
video taken during their experiment. They will be asked to check yes or no and initial beside 
their selection. Options for the use of the video will include reviewing the video to make sure all 
protocols were performed appropriately, as well as use in presentations at conferences. 
Participants will be told that their selection to consent to video will not affect their eligibility to 
participate in the current study. 
 
Participants will also be asked if they would like to be entered into a participant pool and be 
called if future studies may be of interest. This participant pool will be separate from any 
collected data during the study. Participants will be informed that their decision of whether to 
agree to be added to a participant pool will not affect their eligibility to participate in the current 
study. 
 

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Prior to being delegated any informed consent responsibilities, all lab personnel will complete 
the institutional requisite IRB training, observe 2-3 consent processes, and then perform 2-3 
consent processes with the PI or other study investigator present. 
 
All informed consent documents will be stored in a locked file cabinet, in the lab that is also 
locked. All lab personnel will have lab keys (currently just PI, grad students in future). Keys to 
the file cabinet will be kept in a key lockbox, in the lab, that has a 4-digit numerical code that 
only the principal investigator and lab personnel will know. 
13.2 Subject Confidentiality  
Records will be coded by alphanumeric study ID numbers that are linked to participant’s name, 
email and phone number via a master list. This master list will be kept in a separate office from 
data records in a locked file. Participant names will only appear on the research consent form 
and this master list. They will not appear on any data sheets or in any data files kept in the 
laboratory. Names or other information that could be used to identify individuals will not appear 
when results of the study are presented or published. Video records maintained will be altered 
to disguise participant appearance (i.e. no faces or identifiable marks such as tattoos will be 
shown). The video files will be used to quantify movement patterns of subjects during the 
balance tests, as well as a visual record of the experiment. They are filmed from behind the 
participants, so that facial images are not recorded. All research records, including video 
records, are kept on computers accessible only to study staff or in locked archives. 
 
If any subject chooses to withdraw from the study at any point they will be given the choice as to 
whether they want their data or video deleted or if it can still be included in our analyses. This 
will be documented in a revocation form. 
 
Subject confidentiality during identification and recruitment will be protected in the following 
ways. Lower limb prosthesis users that are recruited during clinical visits will be approached by 
their prosthetist in a private clinic room without any other patients present.  
 
Data collections will occur with a single subject at a time and take place in our lab space in the 
UIC Biomechanics Lab (Room 198), with only the necessary research personnel present.    
 
The principal investigator, and properly trained research personnel will be the only individuals 
who will have access to the data. All data will be coded, with the master list linking subjects 
names, emails, and addresses linked to study ID # kept in a locked file in the PI’s office, 
separate from the location of data storage.  This master list is being kept to aid in scheduling 
multiple study visits. No private health information is being collected.  
13.3 Unanticipated Problems 
Unanticipated events will be reported to IRB in a timely manner. 
 
 
 
 
 
 
 

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14.0 
References 
 
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knee amputation. Clin Orthop Relat Res. 1995;319:276-84. 
2. Burger H, Valencic V, Marincek C, Kogovsek N. Properties of gluteus maximus in above-knee 
amputees. Clin Biomech. 1996;11(1): 35–8. 
3. Sherk VD, Bemben MG, Bemben DA. Interlimb muscle and fat comparisons in persons with 
lower-limb amputation. Arch Phys Med Rehabil. 2010;91(7):1077-1081. 
4. Putz C, Block J, Gantz S, et al. Structural changes in the thigh muscles following trans-
femoral amputation. Eur J Orthop Surg Traumatol. 2017;27(6):829-835. 
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amputees, with special regard to the hip joint. Scand J Rehabil Med. 1973;5(2):55-66. 
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and muscle torque in patients after unilateral transfemoral amputation. Appl Bionics Biomech. 
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8. Ranz EC, Wilken JM, Gajewski DA, Neptune RR. The influence of limb alignment and 
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9. Leijendekkers RA, Marra MA, Ploegmakers MJM, et al. Magnetic-resonance-imaging-based 
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11. Allet L, Kim H, Ashton-Miller J, De Mott T, Richardson JK. Frontal plane hip and ankle 
sensorimotor function, not age, predicts unipedal stance time. Muscle Nerve. 2012;45(4):578-
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12. Moirenfeld I, Ayalon M, Ben-Sira D, Isakov E. Isokinetic strength and endurance of the knee 
extensors and flexors in trans-tibial amputees. Prosthet Orthot Int. 2000;24(3):221-225. 
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Rehabil Med.1973;5(1):35-50. 
14. Friel K, Domholdt E, Smith DG. Physical and functional measures related to low back pain in 
individuals with lower-limb amputation: An exploratory pilot study. JRRD. 2005;42(2):155. 
15. Nolan L. A training programme to improve hip strength in persons with lower limb 
amputation. J Rehabil Med. 2012;44(3):241-248. 
16. Russell Esposito E, Miller RH. Maintenance of muscle strength retains a normal metabolic 
cost in simulated walking after transtibial limb loss. PLoS ONE. 2018;13(1). 
17. Raya MA, Gailey RS, Fiebert IM, Roach KE. Impairment Variables Predicting Activity 
Limitation in Individuals with Lower Limb Amputation. Prosthet Orthot Int. 2010;34(1):73-84. 
18. Pauley T, Devlin M, Heslin K. Falls sustained during inpatient rehabilitation after lower limb 
amputation: prevalence and predictors. Am J Phys Med Rehabil. 2006;85(6):521-532. 
 

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19. Pauley T, Devlin M, Madan-Sharma P. A single-blind, cross-over trial of hip abductor 
strength training to improve Timed Up & Go performance in patients with unilateral, transfemoral 
amputation. J Rehabil Med. 2014;46(3):264-270. 
20. van Velzen JM, van Bennekom CA, Polomski W, Slootman JR, van der Woude LH, Houdijk 
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J Rehabil Med. 1973;5(2):88-101. 
 
 
 

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APPENDICES 
 
[Add appendices to your protocol here.  Delete any appendices that are not applicable 
to your research.] 
 
Eligibility Checklist 
Case Report Forms (CRFs)  
Data Collection Tables/Forms 
Questionnaires