The effect of muscle contraction on kinaesthesia

Abstract

Kinaesthesia is our conscious awareness of body position and movement. Experiments are described examining kinaesthetic acuity in human subjects. The results showed a reduced ability to detect limb movement and match limb position during co-contraction of elbow extensors and flexors compared to when these muscles were relaxed. We also report results from animal experiments showing a reduction in muscle spindle stretch sensitivity during fusimotor and skeletomotor activation, a factor that might contribute to the decreased kinaesthetic acuity observed during muscle contraction.