Influence of eccentric actions on skeletal muscle adaptations to resistance training
Article first published online: 8 DEC 2008
© 1991 Scandinavian Physiological Society
Acta Physiologica Scandinavica
Volume 143, Issue 2, pages 177–185, October 1991
How to Cite
HATHER, B. M., TESCH, P. A., BUCHANAN, P. and DUDLEY, G. A. (1991), Influence of eccentric actions on skeletal muscle adaptations to resistance training. Acta Physiologica Scandinavica, 143: 177–185. doi: 10.1111/j.1748-1716.1991.tb09219.x
- Issue published online: 8 DEC 2008
- Article first published online: 8 DEC 2008
- Received 11 March 1991, accepted 17 May 1991.
- capillary suppl;
- concentric and eccentric muscle actions;
- fibre types and size;
- strength training
Three different training regimens were performed to study the influence of eccentric muscle actions on skeletal muscle adaptive responses to heavy resistance exercise. Middle-aged males performed the leg press and leg extension exercises two days each week. The resistance was selected to induce failure within six to twelve repetitions of each set. Group CON/ECC (n= 8) performed coupled concentric and eccentric actions while group CON (n= 8) used concentric actions only. They did four or five sets of each exercise. Group CON/CON (n= 10) performed twice as many sets with only concentric actions. Eight subjects did not train and served as controls. Tissue samples were obtained from m. vastus lateralis using the biopsy technique before and after 19 weeks of training, and after four weeks of detraining. Histochemical analyses were performed to assess fibre type composition, fibre area and capillarization. Training increased (P < 0.05) Type IIA and decreased (P < 0.05) Type IIB fibre percentage. Only group CON/ECC increased Type I area (14%, P < 0.05). Type II area increased (P < 0.05) 32 and 27%, respectively, in groups CON/ECC and CON/CON, but not in group CON. Mean fibre area increased (P < 0.05) 25 and 20% in groups CON/ECC and CON/CON, respectively. Capillaries per fibre increased (P < 0.05) equally for Type I and Type II fibres. Capillaries per fibre area for both fibre types, however, increased (P <0.05) only in groups CON and CON/CON. The changes in fibre type composition and capillary frequency were manifest after detraining. At this time only group CON/ECC showed mean fibre hypertrophy, while capillary density was elevated in groups CON/CON and CON. This study suggests that optimal muscle hypertrophy in response to resistance exercise is not attained unless eccentric muscle actions are performed. The data also show that heavy resistance exercise may produce muscle fibre transformation and capillary neoformation.