Effect of pressure stimulation of Chize (LU5) during pinch action of 50% maximal voluntary contraction on spinal motor neuron function excitability

Abstract

This study examined the effect of pressure stimulation of acupuncture point “Chize (LU5)” during pinch action of 50% maximal voluntary contraction on the excitability of the spinal motor neuron function using F-waves. Fourteen healthy subjects (average age 25.5 ± 2.3 years) were recruited. The subjects were requested to perform a pinch action of 50% maximal voluntary contraction for 1 min (Task 1), and then the same task with an examiner simultaneously performing pressure stimulation to Chize (LU5) for 1 min (Task 2). F-waves were recorded at rest and after the tasks. After Task 1, the F-wave persistence and F/M amplitude ratio increased compared to at rest. After Task 2, the F-wave persistence and F/M amplitude ratio showed no significant difference from at rest. Additionally, the relative values of F-wave persistence and F/M amplitude ratio were significantly higher after Task 1 than after Task 2. These results suggest that pressure stimulation of Chize (LU5) may suppress the excitability of the spinal motor neuron function.