Date of Award
Fall 11-16-2023
Embargo Period
12-11-2025
Document Type
Dissertation - MUSC Only
Degree Name
Doctor of Philosophy (PhD) in Health & Rehabilitation Science
Department
Health Sciences and Research
College
College of Health Professions
First Advisor
Aiko Thompson
Second Advisor
Thomas Sinkjær
Third Advisor
Mark Bowden
Fourth Advisor
Daniel Brinton
Abstract
Propulsive force generation by ankle plantarflexors is important for human locomotion. The production of muscle force involves the coordination of inputs from the tripartite system of locomotion: the central pattern generator-like network, supraspinal descending centers, and peripheral sensory afferents acting on motoneurons. Previous work suggests that during stance phase, sensory afferents contribute significantly to generating and reinforcing plantarflexor activity. Therefore, this project includes three separate studies which aim to investigate muscle afferent contributions to plantarflexor activity towards generating propulsive force during walking at various speeds, additional weight loading, and with restricted knee joint motion. To do this, indirect approximations of each muscle afferents’ firing was examined using ankle joint rotation and ground reaction forces during and prior to peak propulsive force to examine the length- and velocity-sensitive afferents (Ia and II) and load-sensitive afferents (Ib), respectively. In all studies, speed was a factor for each study design as a way of encouraging additional propulsion. Across all studies, as walking speed increased, ankle joint rotation generally decreased its amount and maintained its rate of rotation during mid-late stance. Conversely, ground reaction forces increased in both amount and rate during the same phase. Taken together, these findings may suggest a significant role of the load sensitive Ib pathway in the generation and/or enhancement of plantarflexor activity across various submaximal speeds and during a variety of locomotor tasks. The functional implications of these studies could suggest that enhanced loading of the plantarflexors may be an important strategy for rehabilitation protocols.
Recommended Citation
Damewood, Bridgette Ann Pouliot, "Afferent Contribution to Plantarflexor Muscle Activity Towards Propulsive Force Generation During Walking" (2023). MUSC Theses and Dissertations. 827.
https://medica-musc.researchcommons.org/theses/827
Rights
Copyright is held by Bridgette A. P. Damewood. All rights reserved.