Modeling the influence of body size on vo2 peak: the effects of model choice and body composition. Batterham, Alan M., Paul M. Vanderburgh, Matthew T. Mahar and Andrew S. Jackson. 1School of Social Sciences, University of Teesside, Middlesbrough, TS1 3BA, UK; 2Department of Health and Sport Science, University of Dayton, Dayton, OH 45469-1210; 3Department of Exercise and Sport Science, East Carolina University, Greenville, NC 27858; and 4Department of Health and Human Performance, University of Houston, Houston, TX 77204-5331.
APStracts 6:0264A, 1999.
This study examined the bivariate relationship between peak oxygen uptake (VO2 peak, L.min-1) and body size in adult men (n = 1314, age 17 to 66 yr.), using both _simple_ and _full_ iterative nonlinear allometric models. The simple model was described by VO2 peak = Mb (or FFMb) exp (c SR-PA) exp (a + d Age) _ (where M is body mass in kg; FFM is fat-free mass in kg; SR-PA is self-reported physical activity; _ is a multiplicative error term; and _exp_ indicates natural antilogarithms). The full model was described by VO2 peak = Mb (or FFMb) exp (c SR-PA) exp (a + d Age) + e (_) (where e is a permitted Y-intercept term). The M exponent obtained from simple allometry was 0.65 (95% CI, 0.59 to 0.71), suggestive of a curvilinear relationship constrained to pass through the origin. This _zero Y-intercept_ assumption was examined via the full allometric model, which revealed a M exponent of 1.00 (95% CI, 0.7 to 1.31), together with a positive Y-intercept term (e) of 1.13 (95% CI, 0.54 to 1.73). The FFM exponents were not significantly different from unity in either the simple or full allometric models. It appears that the curvilinearity of the simple allometric model (using total body mass) is fictitious, and is due to the inappropriate forcing of the regression line through the origin. Utilizing FFM as the body size variable revealed a linear relationship between body size and VO2 peak, irrespective of model choice. We conclude that the population mass exponent for VO2 peak is close to unity.

Received 14 September 1998; accepted in final form 2 June 1999.
APS Manuscript Number A815-8.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1999 The American Physiological Society.
Published in APStracts on 22 June 1999