Relationship between oxygen consumption and body mass during treadmill and cycle ergometry respectively

Abstract

In order to study how oxygen uptake can best be scaled to body mass during exercise tests, according to a linear and allometric model, thirteen young male soccer players randomly performed a maximal incremental exercise on both a cycle and treadmill ergometer. The anaerobic threshold (AT) and Threshold of Respiratory Compensated Acidosis (TRCA) were determined from respiratory gas exchange (RGE) parameters. During cycle ergometry, at AT, TRCA and at maximal oxygen consumption (VO2 max), the allometric model normalizes oxygen consumption (VO2) to body weight by dividing the measured value of O2 uptake by body mass raised to the power 0.75. For treadmill running, the suitable body mass exponents were 1.22, 0.94 and 0.75, at AT, TRCA and VO2 max, respectively. For both ergometers, a linear allometric model divides the measured physiological variable values by total body mass. Results show that the allometric function defined above differs between the two ergometers at the AT and TRCA while the difference was negligible at VO2 max. When expressing VO2 to body mass raised to the appropriate mass exponent, at the AT and TRCA respectively, the oxygen uptake was larger for cycling than for running. At VO2 max, the difference between ergometers was not significant. However, when VO2 measures were expressed by the linear model (ml • min−1 · kg−1), the reverse was observed for submaximal exercise: VO2 was greater in value for submaximal treadmill running but no difference was found at VO2 max.