Fast and slow twitch muscles in man

1.(1) An investigation has been made of the twitch responses of 4 different human muscles.2.(2) The first dorsal interosseus muscle of the hand and the extensor digitorum brevis muscle of the foot had twitches which were significantly faster than that of the gastrocnemius and significantly slower than that of the frontalis muscle.3.(3) The results are interpreted as providing suggestive evidence for the existence of fast and slow muscles in man.