PHYSICAL PERFORMANCE IN RELATION TO BODY SIZE AND COMPOSITION

Abstract

Physical performance was determined on a homogeneous group of 65 men between 27 and 44 years of age with a simplified procedure for estimating aerobic capacity. Fatfree weight was derived by densitometry. Total body water, total potassium, total hemoglobin, and blood volume were measured as potential indices of metabolizing tissue involved in exercise. Statistical analysis of the data was performed using stepwise linear regression with ratio of variance tests to select factors most highly correlated with aerobic capacity. A regression equation for predicting aerobic capacity from the knowledge of fatfree weight and potassium is given. Deviations of measured from predicted values are attributed to individual differences in cardiovascular and respiratory competence under stress. Evidence is presented that the magnitude of maximal oxygen consumption relative to fatfree weight is associated with the potassium concentration in the latter. This probably reflects differences in the proportion of muscle present in the fatfree body.