Effects of crank length and seat position on arm cranked ergometry performance

A preliminary series of tests has been conducted to study the influence of shoulder-to-crank-center distance and crank length on maximum power output of healthy adults. It was clear from the trials that the arm trajectories of the subjects changed substantially for different ergometer configurations, although detailed position and orientation information was not gathered. Biomechanically, the shoulder/arm/crank system is underconstrained, i.e. the elbow is free to take on a wide range of positions relative to the shoulder and wrist and still complete the cranking task. Three-dimensional plots of maximum power vs. crank length and horizontal position for each subject showed a bimodal peak, which was still pronounced when all trials for all subjects were combined and averaged.<>