Optimization of Hip-exoskeleton Weight Attributes

Study Overview
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Brief Summary
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The investigators are examining how weight distribution affects the way people walk, in terms of joint kinematics, kinetics, and muscle activity. The investigators are measuring these quantities while people walk while wearing a weighted belt. The investigators distribute the weights and walk for specified periods. They hypothesize that greater weight will have a greater effect on walking.

Detailed Description
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The purpose of this study is to examine how the amount and distribution of weight on the pelvis affects how people walk. The investigators two factors, weight and placement. They are examining how these factors affect muscle activation, joint motions and foot forces. The investigators plan to recruit 40 healthy adult individuals. Each of the 20 experimental conditions (3x3 factorial and one control condition with no weight) will be recorded immediately in a single session. The investigators hypothesize that weight amount, gait speed and weight distribution will all affect how people walk, which will lead towards optimized design of hip exoskeletons.

Official Title
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Evaluating Optimal Weight Design Parameters of a Hip Exoskeleton Designed for Rehabilitation.

Conditions
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Healthy, Gait, Frontal

Intervention / Treatment
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* Other: Weight belt


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Willing to commit to the full experimental session Exclusion Criteria: Functionally relevant lower limb musculoskeletal injury Functionally relevant osteoarthritis and weight bearing restrictions Severe respiratory problems that restrict the wearer from using a metabolic rate apparatus Patients with cardiac issues may be included, but the cardiac issue will be noted in the health history questionnaire

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Weight distribution and placement<br>Changing where weight is distributed on belt around pelvis, specifically, bilaterally, 4th lumbar area, unilaterally on the left side. Also changing amount of weight at 0, 4, 6 and 8 kg. | Other: Weight belt<br>* Wearing belt around waist with various weights attached.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pelvic Obliquity | Amount of pelvic obliquity in response to weighted belt measured using optical motion capture | One day | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Knee Flexion Angle During Swing Phase | Knee flexion angle range of motion measured using optical motion capture | One Day | 
| Integrated Gastrocnemius Muscle Activity During Preswing Phase of Walking | EMG signals were normalized via the mean-dynamic method (Burden and Bartlett, 1999), centering the EMG signal around 1. For data analysis, the EMG signal was integrated along each gait phase to calculate the integrated EMG (iEMG) values. For the gastrocnemius, we extrated the iEMG during the pre-swing phase only. The iEMG was normalized to average during walking, resulting in arbitrary units. | One day |