Pre‐heel‐strike peroneal muscle activity during walking and running with and without an external ankle support

The electromyographic activity of the peroneus longus and brevis muscles was recorded during 100 strides of walking and running on a treadmill in 9 experienced runners with and without an inversion restricting external ankle support. The duration of peroneal activity in the stance phase increased from median 61% of this stage when jogging to 88% when running fast. Pre-heel-strike activity was present in median 10% of all strides when walking, in 28% when jogging, in 40% when running at a medium pace and in 45% when running fast. Application of an external ankle support reduced pre-heel-strike activity by 50% for jogging and medium-pace running. Our results suggest that an unacceptable degree of inversion of the ankle/foot complex in late swing phase produces a stimulus for peroneal muscle contraction before the foot is loaded at heel-strike.