Purpose: Allometry is a method of expressing the relationship between physiological and anatomical variables, which can be used in order to measure the vital capacity through mathematical equations. This study aiming at evaluating lung function indices in order to estimate the maximal aerobic power by respiratory gas analysis device and the allometric equation.

Methods: This study is a descriptive from correlation type, 80 subjects were chosen by convenience sampling. Anthropometric characteristics and dimensions of chest circumference (diameter and depth of the chest) were measured, and Bruce Test was used in order to measure maximal aerobic power. Pearson correlation coefficient and multivariate regression analysis were performed using SPSS version 16.

Results: There is a positive significant relationship between vital capacity and maximal aerobic power (r=0.229 and P=0.041) and between the amounts of the device vital capacity and formula vital capacity(r=1.00 and P=0.00). Accordingly, the following model was developed (chest circumference × 0.284) + (age × 0.319) + (vital capacity × 1.761) + incline = Maximal Oxygen Consumption.

Conclusion: According to the results of this study, there is a significant correlation between device vital capacity and formula vital capacity. Thus, it can be concluded that in order to gain predict of the maximal oxygen consumption, in the absence of accessibility to other experimental methods, allometric equation can be used.