Vector representations of human strength in whole body exertion.

This paper summarises a number of studies of human strength in tasks of static whole body exertion. Measurements were made using a transducer bar which allowed the simultaneous recording of the vertical and horizontal components of any force applied to it by the subject. In each experimental condition, each subject exerted his or herself in all directions in the sagittal plane (ie, that plane which bisects an individual in the antero-posterior direction). Thirty conditions were investigated. Five heights of the bar above the ground, ranging from 1.75 m to 0.25 m, were tested. Various constraints were imposed upon the placement of the subjects' feet. In some conditions a 'ceiling' or 'wall' confined the subject. The results are presented in the form of diagrams which show the magnitude and direction of all possible force vectors in the sagittal plane.