The effectiveness of needling of myofascial trigger points on internal- external muscle peak torque and total work ratios of the shoulder rotator myoatatic unit in overhead throwing athletes suffering from myofascial pain and dysfunction syndrome

Abstract

The purpose of this study was to determine whether dry needling of myofascial trigger points (TrP's), found in the shoulder rotator myotatic unit, had an effect on the peak torque and total work parameters of the shoulder myotatic unit and by inference, the relative external rotation strength deficit in over-head throwing athletes. Athletes who perform overhead throwing sports such as: baseball, javelin, swimming/waterpolo and tennis, are susceptible to sustaining a micro-traumatic injury of the rotator myotatic unit of the shoulder, owing to repetitive high velocity mechanical stress placed on the shoulder at the extreme ranges of motion. The inherent structure of the shoulder, with three external rotators and five internal rotators, causes a muscle imbalance before an activity, such as throwing occurs, and this can predispose an athlete to Repetitive Stress Injuries (RSI) as a result of overuse or overload. The incidence and activation of TrP's in shoulder muscles can be accounted for on the basis of mechanical stress such as overuse / overload and thus could change muscle fiber co-ordination (muscle activity) and precipitate a painful lesion. It can be seen in current literature that TrP's produce a number of signs and symptoms such as: spasm of other muscles, weakness of involved muscle function, loss of co-ordination and decreased work tolerance of the involved muscle . Therefore the TrP's present in the shoulder rotator unit could contribute to changes in internal/external rotation ratios in over head athletes, and thus by deactivating or eliminating these TrP's, it is possible that these ratios may be