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Acoustic and electrical activities during voluntary isometric contraction of biceps brachii muscles in patients with spastic cerebral palsy
Author(s) -
Akataki K.,
Mita K.,
Itoh K.,
Suzuki N.,
Watakabe M.
Publication year - 1996
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/(sici)1097-4598(199610)19:10<1252::aid-mus2>3.0.co;2-d
Subject(s) - isometric exercise , biceps , biceps brachii muscle , spastic , medicine , physical medicine and rehabilitation , cerebral palsy , anatomy , electromyography , muscle contraction , physical therapy
This study was designed to compare electromyogram (EMG) and acoustic myogram (AMG) recordings of biceps brachii muscles in patients with spastic cerebral palsy (CP). The maximal voluntary contraction (MVC) in the CP group was approximately one half of that of the normal group even after being normalized by the muscle cross‐sectional area (CSA) (18.6 ± 5.9 kNm/m 2 in CP, 37.3 ± 2.9 kNm/m 2 in normal). Both CP and normal groups demonstrated a progressive increase in the root mean squared values per unit muscle CSA in the EMG (RMS EMG /CSA) as well as in the AMG (RMS AMG /CSA) with increasing force up to 50% MVC. The increasing magnitude of the RMS EMG /CSAwith force was not significantly different between two subject groups. However, all the levels of force resulted in significantly smaller RMS AMG /CSA in the CP group compared to the normal group. The ratios of RMS AMG to RMS EMG in the CP group (0.75 ± 0.03 m/s 2 /mV) were significantly smaller than those in the normal group (1.37 ± 0.07 m/s 2 /mV) at force levels above 30% MVC. These results suggest that motor disabilities in CP patients are caused not only by primary neural impairment but also by secondary deterioration in muscular contractile properties, probably resulting from muscle fiber atrophy. This appears to be more selective in fast twitch fibers. © 1996 John Wiley & Sons, Inc.