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