Role of central and peripheral signals in force sensation during fatigue.

Five subjects matched the force of a sustained isometric contraction with a contraction of the contralateral muscle. Estimates of the sustained constant forces increased with time despite the direction to disregard the increased effort associated with the fatiguing contraction. These instructions did not produce a noticeable dissociation between effort and achieved force during fatigue as had previously been reported during paresis and tendon vibration.