Background and aims: The validity of five brands of cycle ergometers was evaluated by the comparison of the VO2 requirements at different displayed power.
Methods and results: Five physically active males performed a continuous incremental exercise test on five ergometers (Ergomeca, Lifecycle, Monark, Polar S710 and Computrainer). The latter was also compared with a standard dynamometer in order to associate VO2 values with the real power. Every test started by 5-min warm up on the same cycle-ergometer (Ergomeca) at 100 W to make sure that the VO2 differences do not come from VO2 measurement error. Only last minute steady state VO2 values of each 2-min stage were used for the VO2/Watt curve. Large differences (5 to 10 ml kg-1 min-1) at the same displayed power indicate inaccuracy of displayed power output (PO). Using corrected power values from the dynamometer revealed that for the same VO2 the Computrainer underestimates PO by ~30 W between 100 and 300 W while the Lifecycle overestimate it by 3 to 53 W from 100 to 300 W. The Monark and Polar S710 underestimate PO by 15 W and the Ergomeca by ~5 W.
Conclusion: Inaccuracies between -10 to 18% in displayed PO of various cycle ergometers, question their interchangeability.