Force sensation in isometric contractions: a relative force effect.

A contralateral limb matching paradigm was employed to investigate the perception of isometric forces. Both force and brachial biceps and triceps EMG were recorded from each arm as subjects matched isometric contractions on the basis of equal sensation. It was found that smaller forces were consistently overestimated in magnitude and that the most accurate estimation of force occurred around the middle of the force domain. It is proposed that these results reflect the properties of the biceps muscle which is predominantly involved in gross motor activity.