Date of Award
Fall 11-25-2025
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Physical Therapy
First Advisor
Allison Hyngstrom
Second Advisor
Alexander Ng
Third Advisor
Brian Schmit
Abstract
The purpose of this dissertation was to quantify the benefits of ischemic conditioning on reactive balance responses and gait adaptation during treadmill walking in chronic stroke survivors. Reactive balance and gait adaptations are believed to be limited in this population. Ischemic conditioning is an emerging adjunct to physical therapy that improves motor function post-stroke via improvements in strength, voluntary muscle activation, walking speed, and fatigability. Here, we quantified how ischemic conditioning could impact performance of a more complex task: altering gait to meet various perturbing conditions. Specifically, we quantified mediolateral margin of stability in response to lateral cable pulls (both random, in Aim 1, and repetitive, in Aim 2) at the waist and the number of steps taken to adapt the gait cycle to a split-belt treadmill paradigm (Aim 3). We hypothesized that ischemic conditioning would improve stroke survivors’ ability to alter their gait to meet environmental demands due to increases in voluntary muscle activation. In this series of studies, we observed that stroke survivors who were treated with ischemic conditioning were able to increase their margin of stability to a greater degree in response to both random and repetitive perturbations as compared to a group of individuals treated with a Sham treatment. This increase in margin of stability was accompanied by ischemic conditioning-induced increases in hip abductor muscle activity during perturbation responses. Additionally, we found increased voluntary activation of the knee extensors during maximal voluntary contractions. Finally, we found that IC decreased the number of steps an individual required to adapt their paretic stance time to a split-belt treadmill paradigm. Clinically, the results presented in this dissertation could have significant implications for physical rehabilitation paradigms for stroke survivors. Currently, standard of care paradigms do not effectively address the stroke-induced decrease in the ability to fully activate muscles of the extremities and ability to adapt a motor task, despite evidence that these contribute to overall disability status, muscle weakness, and independence. Ischemic conditioning can be used to address decreased muscle activation and rate of adaptation, ideally increasing functional gains made in a physical rehabilitation program.
Comments
Doctor of Philosophy (PhD)