Influence of induced muscular tension on a time-estimation motor task

Right-handed female volunteers (N=28) participated in a study examining the inverted-U relationship between activation, as altered by various levels of induced muscular tension, and behavioral efficiency. Heart rate and skin resistance were used as measures of activation. A time-estimation task required moving a handle with the right hand across a 60-cm. track in 2 sec. while exerting tension (either 0, 25, 50, or 75% of maximum grip strength) with the left hand on stabilized hand dynamometer. There was no statistical support for the inverted U theory, but the mean performance scores indicated a trend toward the inverted U, with the most accurate mean performance occurring at the 50% induced tension level.