RELATIONSHIP OF MUSCLE-FIBER DISTRIBUTION TO BODY-COMPOSITION IN PHYSICALLY TRAINED AND NORMALLY ACTIVE HUMAN MALES

This study was designed primarily to identify relationships among indi ces of muscle tissue structure (m. vastus lateralis) and of somatic qu alities (anthropometric parameters) in 44 untrained men and 105 well-t rained athletes. The ratio of glycolytic to oxidative muscle fibres wa s significantly less (P<0.05) in endurance athletes as opposed to both the controls and the power athletes. Correlations between anthropomet ric factors and indices of muscle morphology were stronger in trained men, particularly in power athletes. Relationships between body fat an d muscle fibre distribution were low in trained and untrained subjects . Documented muscle plasticity may enhance relationships between somat ic and muscle tissue indices. Our results suggest that the response of the three major muscle fibre types to prolonged training may be relat ively high. Finally, it was proposed that enhanced oxidative capacity of skeletal muscle might be characteristic of those resistant to heart disease.