Establishing Equivalence of Exercise Intensities

Introduction: Research trials that involve testing of physiological response to exercise and that include tests from more than one institution, or tests across long time periods, may be required to include tests from different ergometer types, mainly treadmill or leg cycle ergometer. The purpose of this study was to establish equivalence of metabolic demand when comparing treadmill to cycle ergometer protocols. Methods: Published equations were used to derive external power output performed on a cycle ergometer and treadmill to match external power output performance across the range of typical body weights for subjects. Results: When comparing a submaximal walking versus 10-watt incremental cycling protocol, the percent difference in metabolic demand ranged from -35% to 39% across the range of body weights from 50 kg to 150 kg. For the modified Bruce treadmill protocol, watts on the cycle had to be increased to match metabolic demand as body weight of the subject increases. Conclusion: To match estimated external power output performed on a treadmill, external power output on a leg cycle ergometer must be increased as body weight increases.