Fig. 2. Plantar flexion moment–time history during a maximum voluntary contraction (MVC) from one participant with superimposed twitches. A superimposed twitch was evoked through a triplet electrostimulation (three 500 µs square-wave pulses separated by 5 ms) at the plateau of the MVC. Three more twitches were evoked after the MVC, when the triceps surae muscles were relaxed. The vertical lines indicate the instant of the electrostimulation.