Author ORCID Identifier

0000-0003-4741-5513

Document Type

Dissertation

Date of Award

8-31-2022

Degree Name

Doctor of Philosophy in Biomedical Engineering - (Ph.D.)

Department

Biomedical Engineering

First Advisor

Saikat Pal

Second Advisor

Bryan J. Pfister

Third Advisor

Catherine Mazzola

Fourth Advisor

Joseph A. Zeni

Fifth Advisor

Jean-Francois Daneault

Abstract

The ability to walk or move independently plays a decisive role in one's quality of life. This human ability requires complex coordination with several systems, such as the nervous, muscular, skeletal, and sensory organs, to execute movement tasks. Hence, any disorder of these systems from injury, disease, or aging severely affects the ability to walk or move independently. Disabilities that impair movement severely affect the quality of life. Therefore, studying the changes affecting human movement is necessary to improve the lives of individuals with impaired movement. Since human movement is complex and many systems interact in non-intuitive ways, the overarching objective of this study is to use a combination of motion capture experiments and musculoskeletal simulation to decode human movement.

Muscle co-contraction provides information on motor control. Muscle co-contraction at the ankle and knee during walking, stair use, and walking over uneven surface conditions are assessed in young and healthy older adults. Older adults show greater co-contraction at the knee for stair use, greater co-contraction at the ankle for walking over uneven surfaces, and older women need greater co-contraction for walking over uneven surfaces than older men. These findings suggest that older adults require more effort to employ hip and ankle strategies to adapt movement and maintain balance during ambulation.

In functional electrical stimulation (FES) rowing rehabilitation after spinal cord injury (SCI), knowledge of tibiofemoral (TF) forces are necessary to increase the efficacy of the exercise-based intervention. Since direct measurements are not feasible, a combination of motion capture experiments and musculoskeletal simulations are used to estimate TF force during FES rowing. Peak magnitudes of TF forces for five participants with SCI are estimated. A positive association is found between TF forces and external forces at the feet and ergometer handle. This work may provide the ability to personalize rehabilitation to ensure that an SCI patient receives the minimum mechanical stimulus necessary to maintain bone health.

Exoskeletons have been increasingly used to rehabilitate individuals with SCI and other neurological conditions. A virtual simulator of exoskeletal-assisted locomotion (EAL) is built using controlled experiments and computational modeling. A minimum empirical dataset during exoskeletal-assisted and unassisted locomotion from an able-bodied participant is established. In addition, the dynamics of normal gait and dynamics of exoskeleton-assisted locomotion in an able-bodied adult are compared. The novel virtual simulator provides a foundation for future parametric studies to characterize the effects of human and robot design variables and predictive modeling to optimize human-robot interaction during EAL.

This work investigates the prevalence of muscle co-contractions in older adults, knee joint reaction forces during FES rowing rehabilitation in individuals with SCI, and EAL using a virtual simulator.

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