THE INFLUENCE OF TIBIALIS ANTERIOR MUSCLE-ACTIVITY ON REARFOOT MOTIONDURING WALKING

The purpose of this study was to determine whether tibialis anterior m uscle activity influences the rate of rear-foot motion during walking. Two-dimensional rearfoot motion was recorded from 23 feet. The feet w ere assigned to one of two experimental groups. Muscle activity was re corded from the tibialis anterior muscle using surface electrodes. The early pronators (N = 12) reached maximal pronation within the first 2 0% of the stance phase. The late pronators (N = 11) reached maximal pr onation only after 40% of the stance phase. The results of a t-test sh owed that there was a significant difference (P < .05) in the time to minimal tibialis anterior muscle activity between the two groups. Thes e results indicate that tibialis anterior muscle activity can influenc e rearfoot motion during the stance phase of walking. A clinician shou ld consider the muscular system when evaluating and designing a treatm ent program for patients with foot-related problems. The results of th is study also indicate that static nonweightbearing evaluations alone may not provide an accurate picture of the foot during walking.