Allometric scaling models of isometric biceps strength and the effects of resistance training

The purpose of this study was to (1) derive gender-specific allometric scaling models using pre-training muscle cross-sectional area (CSA) and body mass (BM) as scaling variables, (2) test model appropriateness using regression diagnostics, and (3) cross-validate the models before and after training. A subset of FAMuSS study data (n = 319, females = 183, males = 136) was randomly split into two groups (A & B). Group A pre-training data for female BM, female CSA, male BM, and male CSA models produced scaling exponents of 1.08, 0.44, 0.63, and 0.68, respectively. The female BM model was deemed inappropriate due to non-normal distribution of residuals. All other models met statistical criteria including normal distribution of residuals. Cross-validation to Group B pre-training data revealed that the models were appropriate, with the possible exception of male CSA model. Twelve weeks of resistance training did not alter the relation between BM, CSA, and muscular strength assessed by allometric scaling.