Electromyographic analysis of exercise resulting in symptoms of muscle damage
Deutscher übersetzter Titel: | Elektromyographische Analyse von muskelkatererzeugender Muskelarbeit |
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Autor: | McHugh, M.P.; Connolly, D.A.J.; Eston, R.G.; Gleim, G.W. |
Erschienen in: | Journal of sports sciences |
Veröffentlicht: | 18 (2000), 3, S. 163-172, Lit. |
Format: | Literatur (SPOLIT) |
Publikationstyp: | Zeitschriftenartikel |
Medienart: | Gedruckte Ressource |
Sprache: | Englisch |
ISSN: | 0264-0414, 1466-447X |
Schlagworte: | |
Online Zugang: | |
Erfassungsnummer: | PU199912404977 |
Quelle: | BISp |
Abstract des Autors
Surface electromyographic (EMG) signals were recorded from the hamstring muscles during six sets of submaximal isokinetic (2.6 rad/s) eccentric (11 men, 9 women) or concentric (6 men, 4 women) contractions. The EMG per unit torque increased during eccentric (P<0.0 1) but not during concentric exercise. Similarly, the median frequency increased during eccentric (P<0.0 1) but not during concentric exercise. The EMG per unit torque was lower for submaximal eccentric than maximum isometric contractions (P<0.001), and lower for submaximal concentric than maximum isometric contractions (P<0.01). The EMG per unit torque was lower for eccentric than concentric contractions (P<0.05). The median frequency was higher for submaximal eccentric than maximum isometric contractions (P<0.001); it was similar, however, between submaximal concentric and maximum isometric contractions (P=0.07). Eccentric exercise resulted in significant isometric strength loss (P<0.01), pain (P<0.01) and muscle tenderness (P<0.05). The greatest strength loss was seen 1 day after eccentric exercise, while the most severe pain and muscle tenderness occurred 2 days after eccentric exercise. A lower EMG per unit torque is consistent with the selective recruitment of a small number of motor units during eccentric exercise. A higher median frequency during eccentric contractions may be explained by selective recruitment of fast-twitch motor units. The present results are consistent with the theory that muscle damage results from excessive stress on a small number of active fibres during eccentric contractions. Verf.-Referat