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

Purpose: To assess the reliability of the Kingcycle(TM) ergometer, this study compared peak power recorded using a Kingcycle and SRM(TM) 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 (MAP(C)); and for part 2, nine subjects completed two maximal tests without the stabilizing kit and the Kingcycle calibrated using the standard procedure (MAP(S)). Each MAP(C) test was separated by 1 wk; however, MAP(S) 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 (King(PPO)) and SRM (SRMPPO). Results: Coefficient of variations (CVs) for King(PPO) 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 MAP(C) and MAP(S), respectively. During all tests, King(PPO) was higher than SRMPPO by an average of similar to 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 Kingsycle ergometer.