The perception of effort: an inductive approach.

A theoretical model has been proposed relating physical effort to perceived exertion. The model has been applied to a comparative investigation of the perception of various forces exerted by the adductor pollicis muscle and the quadriceps in five male subjects. The increase in perception of effort with increasing applied force in both muscle groups has been shown to increase exponentially. A force constant, defined in the paper, as the applied force at which perception of effort approximates two-thirds of maximum seems to discriminate effectively between the muscle groups concerned. The description of psychophysical data in this concise quantifiable manner may offer better insight into physiological processes contributing to the appreciation of effort.