Twitch contractile properties of plantar flexor muscles in power and endurance trained athletes

This study compared twitch contractile properties of plantar flexor muscles among three groups of 12 subjects each: endurance and power trained athlet es and untrained subjects. The posterior tibial nerve was stimulated by sup ramaximal square wave pulses of 1-ms duration. Power trained athletes had h igher twitch maximal force, maximal rates of force development and relaxati on and also maximal voluntary contraction (MVC) force. The trained subjects had a smaller twitch maximal force: MVC force ratio and shorter twitch con traction and half-relaxation times than the untrained subjects with no sign ificant differences between the two groups. Thus, the short time for evoked twitches in the athletes compared to the untrained subjects would seem unr elated to the type of training. It is concluded that power training induces a more evident increase of muscle force-generating capacity and speed of c ontraction and relaxation than endurance training.