Output plantarflexion force, M
and F-waves generated at rest and during periods of 20 Hz electrical stimulation before and after the delivery of a vibratory burst. A) Schematic representation of a stimulation pattern showing the time course of two trains of 2 s of 20 Hz electrical stimulation separated by a single 2 s burst of vibration (100 Hz sinusoidal waves). B) Average torque as a function of time (n = 8, thick line) with SD shown in light shade. The arrows indicate the times (rest, Time 1, Time 3 and Time 5) when the Mmax and F-waves responses shown in (C) were obtained. C) Mmax -waves and F - waves recorded from the soleus muscle (10 superimposed repetitions are shown) at the times indicated by the arrows in B. Calibration bars for the Mmax are expressed in mV, while calibration bars for the F-waves are adjusted as a fraction of the corresponding Mmax (i.e. F-waves are normalized to the % of Mmax). Data are from one representative subject.