Effort in isometric muscular contractions related to force level and duration

Abstract

The degree of perceived force involved in squeezing a handgrip dynamometer is shown to grow as a power function of the force of isometric contraction and also as a power function of the duration of the squeeze. The exponent for force turns out to be more than twice that for duration. These two power functions are able to predict measurements of muscle endurance, i.e., of the maximum length of time that contraction of any constant level of force can be sustained. © 1970 Psychonomic Society, Inc.