Activation pattern of Extensor digitorum brevis muscle during child walking

The purpose of the study was the assessment of the activation pattern of Extensor digitorum brevis (EDB) muscle in healthy children, during walking at self-selected speed and cadence. To this aim, the Statistical Gait Analysis was performed on surface electromyographic (sEMG) signals, in a large number (hundreds) of strides per subject. Results from eight healthy children showed a large variability in number of muscle activations, occurrence frequency, and onset-offset instants across strides analyzed. The assessment of the different modalities of activation allowed identifying a single activity pattern, common for all the modalities and able to characterize the behavior of EDB during normal gait. The pattern of muscle activity centered in two main regions of the gait cycle: the second half of the stance phase (detected in 100% of the subjects) and in final swing phase (50%). This ‘‘normality’’ pattern represents the first attempt to develop a reference for dynamic sEMG of EDB in healthy children that is able to include the physiological variability of the phenomenon. The present results could be useful for discriminating physiological and pathological behavior in children and for deepening the maturation of gait.