Measurement of the power output during the acceleration phase of all-out arm cranking exercise.

The purpose of this study was to develop an original friction loaded ergometer allowing measurement of the resisting torque (Mb) and the angular velocity (omega) by means of a force transducer and an optical pick-up during all-out arm cranking exercises. Taking into account the kinetic energy variations of the flywheel, the peak power developed at the crank (P(c)peak) and the peak angular velocity (omegapeak) were determined in 6 male and 6 female able-bodied subjects during 6-8 bouts of 3 s duration, performed at maximal velocity, with Mb varying from 0.07 to 0.87 Nm x kg(-1). In each subject, the Mb increase was related to a decrease of omegapeak. This relationship was expressed through a negative linear regression (0.92 < R2 < 0.99) for omegapeak between 13 and 28 rad x s(-1) for the males and 10 and 24 rad x s(-1) for the females. The relationship between P(c)peak and Mb did not fit well for all subjects (0.01 < R2 < 0.93) with a parabolic equation, indicating that for upper limb testing, the maximal power should be defined as the highest power measured during several bouts performed with appropriate resisting torque. The present study also demonstrated the importance of taking into account the inertia of the moving flywheel during the acceleration phase of an all-out arm crank exercise, when determining the peak power output.