Statistical Analysis of EMG Signal Acquired from Tibialis Anterior during Gait

Aim of the present study was to identify the different modalities of activation of tibialis anterior (TA) during gait at self-selected speed, by a statistical analysis of surface electromyographic signal from a large number (hundreds) of strides per subject. The analysis on ten healthy adults showed that TA is characterized by different activation modalities within different strides of the same walk. The most recurrent modality consists of three activations observed in 37.4±1.9% of total strides: at the beginning of gait cycle, around stance-to swing-transition and in the terminal swing. Further two modalities differ from the most recurrent one because of 1) the continuous activation during swing; 2) a further activity in the late mid-stance. The study of these different modalities of activation suggested that TA acts as pure ankle dorsi-flexor only in a small percentage (~20%) of total strides, where TA activity occurs in the simpler modality. The increase in the complexity of the recruitment of the muscle introduces an uncommon activity during mid-stance, which does not occur for the flexion of the ankle but is related to the activity of the TA as a foot invertor muscle.