Fig. 7. The influence of stretch velocity on the enhancement of twitch force induced by indirect stimulation. (A) A quick (4 ms) or slow (8 s) lengthening step of 6.6% l₀ was applied to a muscle (top trace) and the twitch forces were compared before and after the stretch (lower trace). (B) The slow-time recordings of the same data as in A. Twitch stimuli were applied every 12 s. (C) Comparison of the enhanced forces obtained by fast and slow stretch. The recordings obtained by fast and slow stretches are shown together in each panel (the second, sixth and tenth records after stretch) but the two recordings are almost superimposed.