Comparison of Shoulder Neuromuscular Control in Overhead Athletes with and without Shoulder Hypermobility

Abstract

PURPOSE: A wider range of motion of shoulder joint is necessary for explosive throwing performance and the increase of the range of motion by repetitive throwing is inevitable. The wide range of motion is related with the instability of the joint. Neuromuscular control plays an essential role in stabilizing the joint. However, when the joint becomes hypermobile, how neuromuscular control was affected was not clear. The purpose of this study was to compare shoulder neuromuscular control of overhead shoulder athletes and identify the influence of hypermobility on it.METHODS: Total 24 subjects (hypermobility group (HMG); 12 athletes, normal range group (CON); 12 athletes) were recruited in this research. To assess shoulder neuromuscular functions, joint position sense (JPS), the threshold of detection to passive motion (TTDPM), and force reproduction (FR) were measured.RESULTS: In active JPS at HMG was greater than CON at the 90% target angle, (p<.05). In passive JPS, HMG showed lower JPS compared to CON at the 50% target angle (p<.05). In FR, HMG was lower than CON in internal rotation (p<.05). In relationship test, hypermobility was negatively correlated with active JPS (p<.05).CONCLUSIONS: It was found that the hypermobile shoulder has greater neuromuscular control compared normal range shoulder to compensate for the hypermobility and active sub-system plays a crucial role in the neuromuscular control of the shoulder joint. Thus, it is recommended that neuromuscular training should be considered in training program for overhead athletes with hypermobile shoulder.