Reliability of an air-braked ergometer to record peak power during a maximal cycling test

Purpose: To assess the reliability of the KingcycleTM ergometer, this study compared peak power recorded using a Kingcycle and SRMTM power meters during Kingcycle maximal aerobic power tests.
Methods: The study was completed in two parts: for part 1, nine subjects completed three maximal tests with a stabilizing kit attached to the Kingcycle rig and calibration of the Kingcycle checked against SRM (MAPC); and for part 2, nine subjects completed two maximal tests without the stabilizing kit and the Kingcycle calibrated using the standard procedure (MAPS). Each MAPC test was separated by 1 wk; however, MAPS tests were separated by 54 ± 32 d, (mean ± SD). Testing procedure was repeated for each MAP and peak power output was calculated as the highest average power output recorded during any 60-s period of the MAP test using the Kingcycle (KingPPO) and SRM (SRMPPO).
Results: Coefficient of variations (CVs) for KingPPO were larger than those of SRMPPO; 2.0% (95%CI = 1.5–3.0) versus 1.3% (95%CI = 1.0–2.0) and 4.6% (95%CI = 2.7–7.6) versus 3.6% (95%CI = 2.1–6.0) for MAPC and MAPS, respectively. During all tests, KingPPO was higher than SRMPPO by an average of ∼10% (P < 0.001).
Conclusions: Investigators should be aware of the discrepancy between the two systems when assessing peak power and that SRM cranks provide a more reproducible measure of peak power than the Kingcycle ergometer.