Movement restriction does not modulate sensory and perceptual effects of exercise-induced arm pain.

Abstract

Movement restriction has been proposed as an important modulator of changes in sensory and perceptual function and motor imagery performance that are observed in musculoskeletal pain syndromes. There are no empirical data to support this view. The primary objective of this experiment was to determine the effects of movement restriction on local and widespread sensory, perceptual and motor imagery changes after exercise-induced muscular pain. Further objectives were to investigate whether changes in sensory perception are correlated with pain intensity and tactile acuity or motor imagery performance. In forty healthy volunteers, delayed onset muscle soreness (DOMS) of the non-dominant elbow flexors was induced using eccentric contractions until exhaustion. Participants were then randomised into two groups: a movement restriction group (wearing a sling) or a control group (not wearing a sling). Sensory and perceptual functions were measured using a range of sensory tests and a motor imagery performance task (left/right limb judgements). Movement restriction did not modulate any of the measures. We found concurrent mechanical hypoesthesia (p < 0.01), reduced tactile acuity (p = 0.02) and pressure hyperalgesia (p < 0.01) at the painful side. We found evidence of widespread pressure hyperalgesia. Impaired tactile acuity was associated with a decrease in pain threshold to pressure (r = -0.34, p = 0.03). Motor imagery performance was unchanged (p > 0.35) by pain or movement restriction. Short-term movement restriction did not influence local and widespread sensory changes induced by experimentally induced muscular pain.