The effects of induced muscle tension during tracking on level of activation and on performance.

Abstract

Induced muscle tension has been demonstrated to have significant effects in relation to a wide range of behavioral phenomena. From the behavioral evidence, it appeared reasonable to consider that induced tension was only one of the many ways in which activation level can be varied. It followed that if induced tension were a reliable means of varying activation level, then in addition to the behavioral effects which have already been demonstrated, induced tension should also produce regular and consistent changes in the various physiological indicants of activation. The purpose of this experiment was to investigate such physiological changes. Thirty-eight male college students were trained in an auditory tracking task. Physiological indicants of activation included heart rate, respiration rate, palmar conductance, frontal and occipital EEG, and EMGs from active and passive limbs. Following learning trials, Ss were required to track while squeezing a hand dynamometer in order to maintain one of five predetermined levels of muscle tension. Results clearly showed close agreement between amount of tension induced and the level of activity in all physiological measures. These results were considered in support of a theory that the proprioceptive return from the induced muscle tension produces generalized behavioral and physiological effects indirectly by increasing activity in the reticular activating system.