Abstract
Muscle fatigue is a complex phenomenon that can alter afferent feedback from muscles. It is unclear how proximal muscle fatigue can affect proprioceptive acuity of the distal limb. The goal of the present study was to assess the effects of shoulder muscle fatigue on participants' ability to judge the location of their hand using only proprioceptive cues. Participants' (N = 16) limbs were passively moved outwards by a robot manipulandum and they were instructed to estimate the position of their limb relative to one of four visual targets (two near targets at 10 cm, and two far targets at 20 cm). This estimation task was completed before and after a repetitive pointing task to fatigue (mean performance time: 6 minutes). To assess central and peripheral effects of fatigue, the right arm was fatigued and proprioceptive biases of the left and right hands were determined on different days. Proprioceptive biases and the variability of participants' responses did not change following the fatiguing protocol for either the right or left hand. Similar to previous research (Jones et al, 2010), the results showed that proprioceptive biases differed between hands but not with changes in target distance. Thus, results suggest that proximal muscle fatigue does not affect hand proprioceptive acuity.
