This thesis examined the validity of allometric models (Y = aXbg) in scaling physiological and human performance data (Y) for differences in body size (X). 1) Anaerobic performance. External peak power output (PPO) derived from supramaximalleg ergometry was compared in young adult males and females, using a multivariate allometric model. Estimated fat free mass (FFM) and thigh muscle-and-bone cross-sectional area served as indicators of involved musculature. Male PPO was greater than female (P < 0.05), after allometric adjustment for body size differences. This finding is questionable, however, as the within-gender goodness-of-fit values for the regression models were very poor. 2) Cardiac dimensions. The proper relationships between echocardiographic dimensions [left ventricular (LV) mass, and LV internal dimensions] and various indicators of overall body size [height, body mass (BM), FFM, and body surface area (BSA)] were examined in young, apparently healthy, adult males and females. Scaling by FFM was associated with the least residual error in these samples. The obtained relationships were generally dimensionally consistent, that is, LV mass proportional to FFM to the first power, and LV internal dimensions related to the 1/3 power ofFFM. 3) Methodological issues. The multivariate allometric scaling of peak oxygen uptake by height and BM was investigated. Regression diagnostics revealed that the obtained exponents were unstable, and potentially numerically inaccurate, due to severe collinearity between height and BM in the sample. For elite weightlifting performance, detailed examination of the allometric regression residuals revealed that the model was poorly specified. Re-specification of the model using secondorder polynomials provided the optimal scaling of this data set.