Morphological muscle characteristics in rowers.

Biopsies were taken from the vastus lateralis and deltoid muscle in twelve major senior rowers. Histochemical analyses showed a predominance of the oxidative type I fiber, a low content of the highly glycolytic type IIB fiber, large fiber areas, and a large number of capillaries surrounding the fibers. All these trends were more pronounced in the internationally competitive compared to the nationally competitive rowers. Exceptionally high aerobic capacities and muscular strengths, in competitive rowers, have been reported in previous papers as well as confirmed in the present study. The muscle morphology reported here is in line with the high aerobic demand in race rowing. However, strength has been shown to be more favoured by a high content of type II fibers which may appear contradictory to the present results. This question together with possible effects of physical training on the muscle morphology is discussed.