Graduation Year


Date of Submission


Document Type

Open Access Senior Thesis

Degree Name

Bachelor of Arts



Reader 1

Jenna Monroy

Reader 2

Tessa Solomon-Lane

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© 2024 Mark Tankersley


This study was conducted to observe the effects of changed activity levels due to a major lower extremity injury on ankle function in the uninjured leg. Neuromuscular activation in the Gastric Medialis (GAS) and Tibialis Anterior (TA), the muscles primarily responsible for movement at the ankle, was assessed in 8 athletes at the Claremont Colleges while walking on a flat surface, stepping up a 15º incline, and stepping up a 27º incline. Athletes were split into two groups based on injury condition: a “recovered” group (n=4) who had suffered a major lower extremity injury in the last two years in which the healthy limb was studied and a “healthy” group (n=4) in which either limb was selected. Electromyography (EMG) was used to measure neuromuscular activation and LabChart 8.0 was used to calculate the maximum activation level and integrated area of total activation for each respective step. Data was standardized between subjects by dividing the peak and integrated area from the 15º incline and 27º incline by the flat walking peak and integrated area for each subject. The new standardized values were plotted, and a two-way ANOVA was conducted to test for significant effects from injury condition, ramp height, or their interaction. Significance was found for the impact of ramp height (p=0.0175), subject health condition (p=0.0236), and their interaction (p=0.0472) on the integrated area of GAS activation. No significance was found for the impact of ramp height, health condition, or their interaction for GAS peak activation, TA peak activation, or TA integrated area of activation. There appears to be a trend towards decreased neuromuscular activation in the healthy limb of a recovered athlete compared to the limb of a healthy athlete especially during more demanding tasks. This suggests a reduced ability to recruit muscles to control an uninjured ankle following a major lower extremity injury even after a full recovery. More research should be conducted to explore what implications this may have on optimal physical therapy and recovery protocols.