title: Inertial-load method determines maximal cycling power in a single exercise bout.
abstract: A cycle ergometer was modified to measure power (P) with resistance provided solely by the moment of inertia (I) of the flywheel. P was calculated as the product of I, angular velocity (omega), and angular acceleration (alpha). Flywheel omega and alpha were determined by means of an optical sensor and a micro-controller based computer interface which measured time (+/- 1 microsecond) and allowed P to be calculated instantaneously (PI) every 3 degrees of pedal crank rotation or averaged over one complete revolution of the pedal cranks (PREV). Values for maximum P were identified from each bout (PI max and PREV max). Mechanical calibration of torque via a resistive strap proved this method to be both valid and accurate. Thirteen active male subjects performed four bouts of maximal acceleration lasting approximately 3-4 s with 2 min resting recovery. The mean coefficient of variation for PREV max was 3.3 +/- 0.6% and the intraclass correlation was 0.99. PREV max averaged 1317 +/- 66 W at 122 +/- 2 rpm, and PI max averaged 2137 +/- 101 W at 131 +/- 2 rpm. PREV max and PI max were highly correlated (r = 0.86 and r = 0.80 respectively, P < 0.002) with estimated lean thigh volume. Therefore, the inertial-load method provides a valid and reliable determination of cycling power in one short exercise bout.
authors.affiliation: Department of Kinesiology and Health Education, University of Texas at Austin 78712, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Martin
authors.forename: B M
authors.initials: BM
authors.lastname: Wagner
authors.forename: E F
authors.initials: EF
authors.lastname: Coyle
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D006804:Ergonomics; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000295:instrumentation*; D006801:Humans; D008297:Male; D010807:Physical Endurance; D055585:Physical Phenomena; D010825:Physics; D015203:Reproducibility of Results