Utility of a new lower limb and trunk functional evaluation for pitchers with focus on the physical characteristics of players with a throwing disorder

Objectives A pitching motion involves three-dimensional whole body movement. Proper pelvic and trunk rotation movement are important for the prevention of throwing injuries. Given that throwing is not a simple rotation movement, the evaluation of proper motion should reflect muscle strength as well as coordination and pitching motion characteristics. We have devised a throwing rotational assessment (TRA) as a new evaluation of the total rotation angle required for throwing. The purpose of this study was to examine the characteristics of players with throwing disorders compared to a pain-free group using TRA. Materials and methods The subjects consisted of 164 high school baseball pitchers who participated in a medical check. Pain-induced tests included an elbow hyperextension test and an intra-articular shoulder impingement test. Pitchers who felt pain in either test were classified into a disorder group (n=61). With the subjects in a position similar to the foot contact phase of throwing, the rotation angles of the pelvis and trunk were measured. All tests were performed in the throwing and opposite directions. Results The disorder group had significantly lower average rotation angles of the pelvis and trunk in the throwing direction and the rotation angle of the trunk in the opposite direction compared to the healthy group. Conclusion TRA reflects the complex whole body rotation movement. Reductions in rotational angles as assessed in TRA may be associated with throwing disorders. TRA is a simple method that may be useful in the early detection of a throwing disorder and could be used in the systematic evaluation during a medical check, as well as during self-check in the sports field.