Purpose: The purposes of this study were 1) derive allometric scaling models of isometric biceps muscle strength using pretraining body mass (BM) and muscle cross-sectional area (CSA) as scaling variables in adult males, 2) test model appropriateness using regression diagnostics, and 3) cross-validate the models before and after 12 wk of resistance training.
Methods: A subset of FAMuSS (Functional SNP Associated with Muscle Size and Strength) study data (N = 136) were randomly split into two groups (A and B). Allometric scaling models using pretraining BM and CSA were derived and tested for group A. The scaling exponents determined from these models were then applied to and tested on group B pretraining data. Finally, these scaling exponents were applied to and tested on group A and B posttraining data.
Results: BM and CSA models produced scaling exponents of 0.64 and 0.71, respectively. Regression diagnostics determined both models to be appropriate. Cross-validation of the models to group B showed that the BM model, but not the CSA model, was appropriate. Removal of the largest six subjects (CSA > 30 cm2) from group B resulted in an appropriate fit for the CSA model. Application of the models to group A posttraining data showed that both models were appropriate, but only the body mass model was successful for group B.
Conclusion: These data suggest that the application of scaling exponents of 0.64 and 0.71, using BM and CSA, respectively, are appropriate for scaling isometric biceps strength in adult males. However, the scaling exponent using CSA may not be appropriate for individuals with biceps CSA > 30 cm2. Finally, 12 wk of resistance training does not alter the relationship between BM, CSA, and muscular strength as assessed by allometric scaling.
1Department of Exercise Science and Health Promotion, Florida Atlantic University, Davie, FL; 2Department of Health and Exercise Science, University of Oklahoma, Norman, OK; 3Research Center for Genetic Medicine, Children's National Medical Center, Washington, DC; 4Division of Cardiology, Hartford Hospital, Hartford, CT; 5Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT; 6Center for Lifestyle Medicine and Department of Health Professions, University of Central Florida, Orlando, FL; 7Department of Sport Science and Health, Dublin City University, Dublin, IRELAND; and 8Division of Exercise Physiology, West Virginia University, Morgantown, WV
Address for correspondence: Robert F. Zoeller, Ph.D., Florida Atlantic University, Dept. of Exercise Science and Health Promotion, 2912 College Ave., Davie, FL 33314; E-mail: firstname.lastname@example.org.
Submitted for publication August 2006.
Accepted for publication January 2007.