EFFECT OF D-TUBOCURARINE ON THE SCALING OF EFFORT OF ISOMETRIC MUSCLE CONTRACTIONS.

The purpose of this study was to determine whether the alteration in voluntary strength produced by d-tubocurarine, and the consequent reduction in feedback from the muscles, would distort a subjects normal reference for judging the effortfulness of a task, and change the slope of the effort function. The effort function obtained with d-tubocurarine was not significantly different from those secured in the normal and placebo conditions. Thus, it was concluded that the motor units remaining functional after the administration of d-tubocurarine fatigue normally, and that the slope of the effort function is determined by the relative rather than the absolute number of motor units required to maintain the contraction. Author