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Abnormal use of remaining motor units during locomotion in peroneal palsy
Author(s) -
Grimby Lennart,
Holm Kerstin,
Sjöuström Lars
Publication year - 1984
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880070411
Subject(s) - gait cycle , physical medicine and rehabilitation , medicine , stride , leg muscle , gait , electromyography , physical therapy , physics , kinematics , classical mechanics
Abstract The firing properties of single anterior tibial motor units were studied (during walking) with electromyogram (EMG) techniques in five normal subjects and in 10 patients who had footdrop due to an acute lesion of the common peroneal nerve. In the normal subjects, high threshold units did not fire in the ordinary step cycle and low threshold units fired at 10–25 Hz. In half of the paralyzed subjects, all motor units fired at 40–50 Hz for more than 200 msec in each step cycle, which could be sufficient for maximal force. In the other half of the paralyzed subjects, high threshold units were not reruited in each step cycle and low threshold units fired at 15–35 Hz, indicating that there were force reserves which were not used to prevent footdrop in each stride.