Recording of medial gastrocnemius monopolar signals. Recording of non-propagating monopolar EMG signals. (a) Schematic representation showing subject position. The ankle axis of rotation (i.e., the lateral malleolus) was aligned to the transversal axis of the force-plate. The plantar flexion torque (My) with respect to the force-plate transversal axis was computed as My = (Fz
)/4 and was displayed as a feedback to the subject. (b) The electrode matrix (8 rows and 16 columns) was positioned on skin regions covering exclusively the medial gastrocnemius muscle. The position was confirmed by ultrasound scanning. (courtesy of Dr. Taian Vieira, reproduced with permission ).