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 men 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 with a 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– 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, whereas the Lifecycle overestimate it by 3–53 W from 100 to 300 W. The Monark and Polar S710 underestimate PO by 15 W and the Ergomeca by ~5 W.
Inaccuracies between –10% and 18% in displayed PO of various cycle ergometers question their interchangeability.