Intrinsic Foot Muscle Morphology in Active Runners With and Without a History of Exercise-Related Lower Leg Pain

Abstract

Our objective was to quantify the functional and morphological characteristics of the plantar intrinsic muscles in those with and without a history of exercise-related lower leg pain (ERLLP). Thirty-two active runners—24 with a history of ERLLP—volunteered. Strength of the flexor hallucis brevis and flexor digitorum brevis, postural control, and navicular drop were recorded. Morphology of the abductor hallucis, flexor digitorum brevis, and flexor hallucis brevis muscles were captured using ultrasonography. Those with ERLLP had smaller flexor hallucis brevis morphology measures (p ≤ .015) and a greater reliance on visual information while balancing (p = .05). ERLLP appears to alter intrinsic muscle function and morphology.