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Contractile properties and fatigue of quadriceps muscles in multiple sclerosis
Author(s) -
de Haan Arnold,
de Ruiter Cornelis J.,
van der Woude Luc H.V.,
Jongen Peter J.H.
Publication year - 2000
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 - 10.1002/1097-4598(200010)23:10<1534::aid-mus9>3.0.co;2-d
Subject(s) - isometric exercise , muscle fatigue , medicine , quadriceps muscle , multiple sclerosis , physical medicine and rehabilitation , cardiology , electromyography , muscle contraction , endocrinology , physical therapy , psychiatry
Functional characteristics of electrically stimulated quadriceps muscles of patients with multiple sclerosis (MS) were determined to investigate whether adaptations in muscle properties contribute to the higher fatigability of these patients. The estimated maximal isometric force generating capacity of MS patients was only 11.2% ( P < 0.05) lower than control subjects. However, the patients were only able to voluntarily exert 75 ± 22% ( n = 12) of their maximal capacity, against 94 ± 6% ( n = 7) for the control subjects. There were no differences in muscle speed, suggesting that muscle fiber distribution was not different in the MS patients due to reduced muscle usage. During a series of repeated contractions, greater decrements occurred in isometric force and in maximal rate of force rise in the MS patients (by 31.3 ± 10.3% and 50.1 ± 10.0%, respectively; n = 13) than control subjects (23.8 ± 6.6% and 39.0 ± 8.1%, n = 15), suggesting a lower oxidative capacity. The results indicate that increasing the mass of their muscles by training may help to reduce the excessive muscle fatigue of MS patients. © 2000 John Wiley & Sons, Inc. Muscle Nerve 23: 1534–1541, 2000