Peroneus longus and the midfoot in children: EMG normative data
hamstrings (HA) and were compared between lower limbs according to the degree of induce equinus. The data were divided into nine intervals in relation to the phases of the motion as described by Perry. Results.– On the lower limb with the orthosis, the activation of the SOL was earlier from 73–100% and 0–50% of the cycle (coactivation SOL-TA) and the amplitude increase from 108 of dorsiflexion (P < 0.01). From 0 to 10% of cycle, the TA amplitude decreases from 208 (P < 0.01). From 108 of dorsiflexion, the HA activation significantly increase from 0 to 10% of the cycle. The DA activation decrease from 0–10% cycle (P < 0.05) and like the VL, a muscular activation appear in the middle of stance phase 208 (VL 20–30%: P < 0.05). The contralateral limb, SOL activated earlier from 87–100% and 0– 10% at MP (P < 0.01). Discussion.– Equinus gait secondary to the orthosis induced changes in muscle activation both in terms of timing and in terms of signal amplitude. The premature activity of SOL, the TA-SOL coactivation and the reduce TA amplitude are frequently observed during cerebral palsy gait. These findings in healthy children show that a foot deformation without neurological disturbance induce primary changes in muscle activation, which must be taken into account during interpretation in motion analysis.