Evidence of discrepancy in resistive force transmission during a friction loaded high intensity cycle ergometer calibration procedure

The purpose of this preliminary study was to examine a standard calibration procedure used for high intensity cycle ergometry using a Monark 864 cycle ergometer. Results indicated that resistive force transmission to the ergometer flywheel is attenuated at loads above 3 kg and is represented by a departure from linearity. Measurements of cycle ergometer head displacement indicate large deflections during a static calibration test. Differences were observed in load application between static and dynamic conditions, with dynamic tension being underestimated. Significant differences (p < 0.0001) in voltage measurements recorded at the rope tension sites were observed between static and dynamic conditions. During static conditions, values of 182 ± 94.9 mV were recorded compared with 104.9 ± 56.8 mV recorded during dynamic conditions. Results indicate that a dynamic calibration procedure overestimates the resistive force transmitted to the flywheel of the ergometer. The results may also have implications in the assessment of aerobic ability using cycle ergometers. Also, the design of the ergometer appears to be questionable in the assessment of high intensity exercise physiology and performance.