The pitching motion requires neck, trunk and hip rotations. The purpose of this study was to investigate the relationship between pitching injuries and dominant versus non-dominant differences of the ranges of these motions. The subjects were 66 high school baseball pitchers who received medical checkup during baseball classes in Kyoto prefecture. During medical checkup, physical therapists measured the ranges of neck/trunk rotations, and internal rotation of the bilateral hips. Then orthopaedic doctors did special tests such as shoulder internal impingement test, subacromial impingement test, elbow valgus stress test and elbow hyper extension test. Fourteen pitchers (21.2%) who were positive in one or more special tests were judged to require second screening (injured group). In normal group, average neck/trunk rotations toward the non-dominant side were significantly wider than rotations toward the dominant side. Average hip internal rotation was significantly wider on the non-dominant side than on the dominant side. In injured group, a larger number of pitchers had wider neck and trunk rotation ranges toward the dominant side than toward the non-dominant side, and had wide hip internal rotation range on the dominant side compared to the non-dominant side. Comparing the ranges of the neck/trunk rotations and hip internal rotation between dominant and non-dominant sides might be useful for the prediction of pitching injuries of the shoulder and the elbow.

Background: Massive rotator cuff tears (MRCTs) with subscapularis (SSC) tears cause severe shoulder dysfunction. In the present study, the influence of SSC tears on three-dimensional (3D) shoulder kinematics during scapular plane abduction in patients with MRCTs was examined. Methods: This study included 15 patients who were divided into two groups: supraspinatus (SSP) and infraspinatus (ISP) tears with SSC tear (torn SSC group: 10 shoulders) or without SSC tear (intact SSC group: 5 shoulders). Single-plane fluoroscopic images during scapular plane elevation and computed tomography (CT)-derived 3D bone models were matched to the fluoroscopic images using two-dimensional (2D)/3D registration techniques. Changes in 3D kinematic results were compared. Results: The humeral head center at the beginning of arm elevation was significantly higher in the torn SSC group than in the intact SSC group (1.8±3.4 mm vs. −1.1±1.6 mm, p<0.05). In the torn SSC group, the center of the humeral head migrated superiorly, then significantly downward at 60° arm elevation (p<0.05). In the intact SSC group, significant difference was not observed in the superior-inferior translation of the humeral head between the elevation angles. Conclusions In cases of MRCTs with a torn SSC, the center of the humeral head showed a superior translation at the initial phase of scapular plane abduction followed by inferior translation. These findings indicate the SSC muscle plays an important role in determining the dynamic stability of the glenohumeral joint in a superior-inferior direction in patients with MRCTs.

Pitching motion is made up by three-dimensional whole body movement. Pelvic and trunk rotation movement is important for the prevention of throwing injuries. Throwing is not a simple rotation movement. Evaluation should reflect muscle strength, coordination, and pitching motion characteristics. We have devised throwing rotational assessment (TRA) similar to throwing as the new evaluation of total rotation angle required for throwing. The purpose of this study was to introduce the new method and to examine the characteristics of players with throwing disorders. The subjects were 76 high school baseball pitchers who participated in the medical check. Pain-induced tests were elbow hyperextension test and intra-articular shoulder impingement test. Pitchers who felt pain in either test were classified as disorder group. TRA evaluation was performed as follows. In the positions similar to the foot contact phase, rotation angles of the pelvis and trunk were measured. In the position similar to follow through phase, the distance between the middle finger and the second toe was measured. All tests were performed in the throwing and opposite direction. Twenty five pitchers were classified as disorder group. All TRA tests in healthy group were significantly higher in the throwing direction than in the opposite direction, but there was no significant difference in the disorder group. Disorder group had significantly lower average rotation angles of the pelvis and trunk in the throwing direction and rotation angle of trunk in the opposite direction than the healthy group. Restrictions on TRA reflecting the complex whole body rotation movement may be related to the throwing disorder. This evaluation is a simple method. It would be useful early detection of throwing disorder and systematic evaluation in medical check, as well as self-check in the sports field.

Abdominal draw-in is a functional transversus abdominal muscle exercise to acquire the contraction. However, it is difficult for even healthy subjects to selectively contract the deep transversus abdominal and internal oblique muscles without over-contraction of the superficial rectus abdominis and the external oblique muscles. This study examined whether the transversus abdominal muscle is selectively contracted by our taping method. The subjects were 20 healthy males. Using ultrasound, we compared the thickness of external oblique, internal oblique, and transversus abdominal muscle among no taping, kinesio taping and abdominal muscle activation taping in the standing position. The thickness of transversus abdominal muscle significantly increased in the activation taping more than the other methods. This study showed that abdominal musculature activation taping made it possible to contract the transversus abdominal muscle selectively.