Biceps brachii: concentric and eccentric contraction

A grid if 8x8 electrodes (diameter = 3mm, interelectrode distance = 10 mm), assembled on an elastic sleeve, is applied to the biceps brachii. The video shows the original (non-interpolated) map of the the RMS value of the longitudinal single differential signal computed on epochs of 0.25 s duration (4 maps/s). Observe the map during the concentric phase (slow elbow flexion, weight lifted up) and the eccentric phase (slow elbow extension, weight dropped down). The activations of the short and long head of the biceps can be distinguished. Compare with video N. 10.