Mechanical responses of human hypothenar and calf muscles in normal and pathological states

Abstract

made the first direct approach succeeding in stimulating single motor units by threshold stimulation in the extensor digitorum brevis muscle, recording their twitches by electronic averaging; thus they could demonstrate the existance of two populations of units, fast and slow, within the muscle.Recently we have studied the human hypothenar and calf muscles characte ristics in normal subjects and in some pathological conditions. The results are reported here. MATERIAL AND METHODSSubjects -The hypothenar muscles were investigated in 32 normal subjects aged between 14 and 60 years old; 16 were females and 16 were males. In 16 subjects the examination was performed on both hands and in 28 the number of active motor units in the hypothenar muscles was estimated following a technique described elsewhere 21.