The silent period was measured from the stimulus artefact (vertical arrow) to the resumption of voluntary EMG activity (panel A). The end of the silent period was determined when rectified EMG activity reached the mean value extended by 2 standard deviations of the rectified EMG signal recorded during ∼1 s when subject was at rest before the contraction (Resting EMG). The relations between the duration of the silent period following transcranial magnetic stimulation and stimulus intensity for the soleus (SOL) (panel C) and medial gastrocnemius (MG) (panel D) during isometric (circles), shortening (squares) and lengthening (triangles) maximal voluntary contractions (MVCs) are illustrated for the group (means ± SEM). The duration of the silent period, recorded for the greatest stimulus intensity, is compared for lengthening (hatched bars), isometric (open bars) and shortening (filled bars) MVCs (panel B). For each contraction type, data represent means ± SEM for 12 subjects. ***Significant difference at P < 0.001: lengthening vs. isometric and shortening.