Fig. 3

Normalized displacement over time with the different computed phases. 1 The “elongation phase” of the upper-limb (extension of the elbow), 2 The “plateau-1”: phase of maintenance in a position of maximum upper-limb elongation, 3 the “retraction phase”, return to the initial position, 4 the “plateau-2” phase in the initial retracted position, elbow bent, before initiating a new extension-flexion cycle