PURPOSE: The purpose of this study was to 1) derive allometric scaling models of isometric biceps strength 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. METHODS: A subset of FAMuSS* study data (n = 183, age = 24.4 +/− 6.0 yrs) was randomly split into two groups (A & B). Allometric scaling models were derived for Group A and cross-vaildated on Group B. RESULTS: Group A pre-training data for BM and CSA models produced scaling exponents of 1.08 and 0.44 respectively. The allometric scaling model using CSA, but not BM, met all statistical criteria. To further investigate the relation between BM and isometric strength, Group A was subdivided into 2 groups based on BMI (<25 vs. >/=25), yielding a scaling coefficient of 1.48 for the BMI <25 group that met statistical criteria. No significant relation between BM and strength was found for the BMi>/+25 group. Cross-validation to Group B pre-training data revealed that the CSA model and BM model (for BMI <25 group) were appropriate. CONCLUSIONS: These data suggest that the relation between BM and strength in females may be influenced by adiposity. Twelve weeks of resistance training did not alter the relation between BM, CSA, and isometric biceps strength as assessed by allometric scaling. *Functional SNP's (single nucleotide polymorphisms) Associated with Muscle Size and Strength