Researcher(s)
- Benjamin Wisniewski, Mechanical Engineering, University of Delaware
Faculty Mentor(s)
- Jill Higginson, Mechanical Engineering, University of Delaware
Abstract
Stroke is a leading cause of disability in the United States. Post-stroke individuals typically generate reduced propulsion force from the paretic limb during walking, while contralateral propulsion remains largely unaffected. Visual biofeedback, which provides real-time information about muscle activity, has become a possible rehabilitation tool, but determining its effects on contralateral muscle activation during gait requires further research. This pilot study investigated how visual biofeedback targeting the soleus muscles of the paretic limb influences muscle activation in the contralateral limb.
Four healthy individuals participated in the pilot study. Surface electromyography (sEMG) sensors were placed over both soleus muscles while participants walked on a dual-belt force-plate instrumented treadmill at a self-selected speed. Following a baseline walking trial, participants received real-time soleus EMG biofeedback to decrease muscle activation by 20-30% below the baseline (low target) and increase muscle activation by 20-30% above baseline (high target). The order of the target conditions was randomized. Following each training condition, a 30-second post-training walking trial was recorded to see any changes in EMG and anterior-posterior ground reaction force (APGRF).
Analysis was completed with custom MATLAB code and demonstrated that participants had varied responses to the visual biofeedback. During the high biofeedback condition, paretic soleus EMG and APGRF increased relative to baseline and maintained higher values through post-trial conditions, whereas both measures decreased during the low biofeedback and the post-trial conditions. The contralateral limb showed reductions in average EMG activity and APGRF during the high condition, but the low condition produced smaller and less consistent changes.
Although individual responses varied, these preliminary findings suggest that modifying paretic limb activation through visual biofeedback may influence muscle activation and propulsion in both limbs. Additional research with a larger sample size would be needed to determine the significance of contralateral muscle activation, especially for the low target.