Subjects and methods. The investigators studied 18 ambulatory children with dynamic equinus foot deformity (mean age 6.1 years). The gastrocnemius muscle on the affected side was injected with BoNT-A (Dysport, range from 8.9-19.4 U/kg). As the primary neurophysiological outcome measure, compound muscle action potential (CMAP) areas were assessed in the lateral gastrocnemius (LG) and tibialis anterior(TA) muscles on the treated and untreated side before BoNT-A injections (T0), and on days 10 (T10), and 30 (T30) after injections. Clinical scales were assessed and video gait was analyzed at all three time points.