Effects of strength training and immobilization on human muscle fibres

Autor: MacDougall, J. D., Elder, G. C. B., Sale, D. G., Moroz, J. R., Sutton, J. R.
Zdroj: European Journal of Applied Physiology; February 1980, Vol. 43 Issue: 1 p25-34, 10p
Abstrakt: Seven healthy male subjects were studied under control conditions and following 5–6 months of heavy resistance training and 5–6 weeks of immobilization in elbow casts. Cross-sectional fibre areas and nuclei-to-fibre ratios were calculated from cryostat sections of needle biopsies taken from triceps brachii. Training resulted in a 98% increase in maximal elbow extension strength as measured by a Cybex dynamometer, while immobilization resulted in a 41% decrease in strength. Both fast twitch (FT) and slow twitch (ST) fibre areas increased significantly with training by 39% and 31%, respectively. Immobilization resulted in significant decreases in fibre area by 33% for FT and 25% for ST fibres. The observed nuclei-to-fibre ratio was 10% greater following the training programme. However, this change was non-significant. There was also a nonsignificant correlation between the magnitude of the changes in fibre size and the changes in maximal strength following either training or immobilization.
Databáze: Supplemental Index
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