The Live Long Walk Strong Rehabilitation Program: What Features Improve Mobility Skills?
Phase: NA
Conditions: Mobility Limitation
Sponsor: VA Office of Research and Development

Title of Study: The Live Long Walk Strong Rehabilitation Program: What Features 
Improve Mobility Skills? 
NCT 04026503 
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Primary Outcome: The primary outcome for all aims of this study is usual Gait Speed,.53,54 Gait 
speed is recorded by stopwatch over a 4-meter walking course beginning from a standing start. 
The fastest of 2 trials is recorded in meters/seconds. Declining gait speed is associated with 
heightened risk for adverse health outcomes (hospitalization, disability, death) over 1-4 years of 
subsequent follow up. 53,54 Changes in gait speed of .05 and 1.0m/s are characterized as small 
and large clinically meaningful differences respectively. 24,55 For Aims 2 & 3, we will identify 
factors that mediate changes in gait speed. Our experience with LLWS and related clinical trials 
identifies that the majority of participants (> 70%) exceed a .09 m/s change after treatment.]  
 
 
Timing and coordination of gait 
Smoothness of walking is our primary measure of timing and coordination and is an integrated 
measure of motor control of walking. 37,56 It is assessed during usual over ground walking. 
Linear acceleration of the body is measured along three axes (vertical, anterior-posterior and 
medial-lateral) using a tri-axial accelerometer attached to the skin over the lumbar spine (L3 
segment). Trunk accelerations are sampled at 200 Hz and used to calculate the harmonic ratio 
following the methodology of Menz. 37,56 The harmonic ratio is derived in the vertical, medial-
lateral and anterior-posterior directions. Higher harmonic ratios indicate greater levels of 
functioning. Our prior work reports mean changes of 25-30% in smoothness of walking occur 
with training. 18 
Gait variability will be a secondary outcome and is defined as fluctuations in gait characteristics 
from one step to the next.57 It is an indicator of impaired mobility in older adults40 and will serve 
as a secondary indicator of timing and coordination. Gait variability is quantified using 
established measures of temporal and spatial gait characteristics including stance time, step 
length, and step width. Variability will be calculated as the standard deviation of the set of steps 
recorded over 4 passes on the ZenoMat, an instrumented walkway. Approximately 32 steps will 
be collected from 4 passes on the ZenoMat which will be more than adequate to achieve a 
stable measure of gait variability. Our prior work has shown that 20 steps are sufficient to 
achieve a reliability of 0.75 and 30 are sufficient for 0.80.40,58 In general, lower variability is 
better. 
 Leg Power, Leg strength and Leg Velocity will be measured separately for each leg by 
determining a 1 repetition maximum (1RM) from 6 to 12 trials on a leg press machine (Keiser 
Pneumatic Leg Press; Fresno, CA).    Leg muscle power is measured separately on each leg 
using the same equipment.  Five repetitions will be performed at 40% and 70% 1RM. The 
highest value of the repetitions will be recorded. Peak leg velocity is derived from power 
recorded at 40% of the 1RM, by the formula Velocity=power/0.4(1RM). The test-retest reliability 
of these measures is excellent (r >.85).42,59,60 Leg power will be our primary outcome measure 
whereas leg strength and leg velocity will be secondary outcomes. A 9-10% change in leg 
power is clinically meaningful and our proposed treatment approach can exceed that threshold 
(see study 3, preliminary work). 61 
Trunk Extensor Muscle Endurance is measured using a technique that is reliable and valid 
among community dwelling older adults. 31 This is measured while the participant is lying prone 
on a specialized plinth positioned 45 degrees from vertical.  Subject’s feet are supported on a 
footplate and fixed in position. A portion of the table that is hinged and positioned at waist level 
is lowered to the horizontal plane and subject is asked to maintain their position as long as 
possible with their arms across his chest. The test is terminated when the subject can no longer 
maintain the unsupported position or after 150 seconds. Time is recorded in seconds and only 
one trial is performed. Reliability for the trunk measure is excellent (r=.88-91).31 We have 
observed mean changes of 48% with LLWS (see study 3, preliminary work). 

Self-Efficacy Scale for Exercise is an established, reliable and valid scale measuring an 
individual’s confidence to engage in exercise. 45,62 It is sensitive to change and successfully 
utilized within studies of older adults with mobility problems, including our previous RCT among 
hip fracture patients.45,62  
Secondary Outcome Measures: [The SPPB total score will be a secondary outcome for each 
aim. The SPPB is a well-established, valid and reliable physical performance measure used 
extensively in aging research. It is a composite measure of three functional tasks: usual gait 
speed over 4 meters from a standing start, 5 times repeated chair stand, and progressive 
standing balance. Each task is scored between 0-4 (higher score corresponds to better 
performance), with a maximum summary score of 12. Each increment decline in SPPB total 
score is associated with heightened risk for adverse health outcomes.53,54 Changes in SPPB of 
0.5 units and 1.0 units are characterized as a small and large clinically meaningful differences 
respectively. 24,55The Late Life Function and Disability Instrument (LLFDI) will also be a 
secondary mobility outcome. The LLFDI is a reliable patient-reported (by interview or phone) 
measure of functional mobility validated in a wide range of older adult populations, having been 
used in over 70 clinical trials worldwide.63 We have previously reported that LLFDI-Function and 
its sub domains are very sensitive to change. 35 Scores for all domains are scaled between 0-
100 and clinically important differences are defined.] 64  
Covariates & potential confounding variables: Clinical characteristics including age, gender, 
educational attainment, race, and marital status will be recorded. Height and weight will be 
measured using standardized methods and body mass index (BMI) will be calculated as weight 
(kg) divided by height in squared meters..65 Comorbidity will be measured using a valid and 
reliable questionnaire that allows for the characterization of whether these conditions require 
treatment or impact physical function. 66  Depression will be measured by the 10-item Center for 
Epidemiologic Studies-Depression Scale (CES-D), 67,68 a widely used screening tool for 
symptoms of depression that discriminates well between general population samples. The Brief 
Pain Inventory questionnaire will measure pain.69,70 Falls, fall related injuries and illnesses will 
be recorded via monthly calendars.71 Also, we will administer the Activities-specific Balance 
Confidence (ABC) Scale, which is a well-established and validated scale measuring confidence 
with balance and mobility.62,72 Given the strong association between mobility skills and 
cognition, participants will also undergo the NIH toolbox cognition battery. 73 Knee and ankle 
range of motion will be measured using a goniometer. Maximal knee flexion and extension are 
measured in degrees, while the ankle range of motion is measured as a binary measure for both 
dorsiflexion (ability or inability to dorsiflex to 90 degrees) and plantarflexion (ability or inability to 
plantarflex 20 degrees). Reliability for this measure is excellent (r=.82-.98).74 [Every 4 weeks of 
study participation, we will assess physical activity and exercise engagement among all 
participants. Physical activity will be measured via the Phone-Fitt, 9 a measure ascertainable by 
phone or in person that is validated against actigraphy measures. Exercise engagement will be 
measured by self-report as specified in section 3.G.vi.]