Comparison of passive torque during shoulder internal rotation before and after a pitching in college baseball pitchers / 体力科学

Previous study reported that baseball pitchers had a decreased shoulder internal rotation (IR) range of motion after pitching. However, whether the decreased range of motion associated with pitching is caused by tightness of the posterior shoulder has not been clarified yet. The joint stiffness in the passive torque can be compared with posterior shoulder tightness before and after pitching. Hence, this study aimed to compare shoulder IR stiffness based on passive torque before and after pitching in baseball pitcher. Eleven health male collage baseball pitchers were recruited. Passive torque during IR (max IR, peak torque and stiffness) of dominant and non-dominant arms was measured using an isokinetic dynamometer. Measurements were taken before, after, and post 24 hours after pitching (105 pitches). It was observed that after pitching, max IR and peak torque were significantly decreased compared to those before pitching. However, there was no difference in the stiffness of passive torque among three measurements. In conclusion, healthy college baseball pitchers have a decreased IR range of motion after pitching. However, this result is not due to posterior shoulder tissue tightness, but because of altered stretch tolerance.

Scapulothoracic Bursitis in a Amateur Baseball Pitcher / 대한스포츠의학회지

Scapulothoracic bursitis refers to inflammation of the bursae secondary to trauma or overuse owing to sports activities or work. It usually causes persistent pain and scapulothoracic crepitus by irritation of bursa but can be presented as painless mass around chest wall. We report a case of scapulothoracic bursitis in a baseball pitcher presenting as rapidly growing chest wall mass confused with a soft tissue tumor. Computed tomography and magnetic resonance imaging revealed as a well-demarcated cystic mass situated between the scapula and chest wall. Incisional drainage resulted in complete resolution of the mass within a couple of weeks. Scapulothoracic bursitis may be presented as painless huge mass in overhead sports athlete and one of the differential diagnoses of soft tissue tumor of the chest wall.

The relationship between asymmetric characteristics of muscle thickness and ball speed in baseball pitchers / 体力科学

The primary purpose of this study was to investigate whether the baseball pitchers have asymmetric characteristics of muscle thickness (MT) in upper extremities, trunk, and lower extremities because of repetitive pitching. The secondary purpose of this study was to investigate the relationship between MT and ball speed. Twenty-six college baseball pitchers participated in this study. Twenty-six sites were selected to quantify the asymmetric characteristics of MT. The MT was measured by a B-mode ultrasound. The ball speed, measured by a radar gun, was used to quantify the pitching performance. The MT of forearm, subscapula, and chest in dominant side (pitching side) were significantly greater than those in nondominant side, and the MT of abdomen, lateral abdomen, and anterior thigh in nondominant side were significantly greater than those in dominant side. On the other hand, the MT of forearm in both sides and the MT of lateral abdomen in dominant side were significantly and positively correlated with ball speed. These results suggest that asymmetric muscle thickness in upper extremity, trunk, and lower extremity in baseball pitchers resulted from repetitive pitching, and the MT of forearm and lateral abdomen are related to the ball speed.

MUSCLE VOLUME AND STRENGTH CHARATERISTICS OF THE ROTATOR CUFF AND DELTOID MUSCLES IN ASYMPTOMATIC BASEBALL PITCHERS / 体力科学

The purpose of this study was to investigate muscle volume (MV) and strength characteristics of the rotator cuff (supraspinatus, infraspinatus, teres minor, and subscapularis) and deltoid muscles in each shoulder of asymptomatic baseball pitchers. Twelve collegiate baseball pitchers (PG) and ten male students (CG) who never played an overhand sports volunteered to participate in this study. Magnetic resonance imaging (Straits II, Hitachi Medico, 1.5 T) was used to measure the MV of rotator cuff and deltoid muscles in both shoulders of each subject. Since the individual muscles were difficult to identify on MRI scans, the infraspinatus and teres minor were analyzed as one infraspinatus muscle. Shoulder abduction (ABD), external rotation (ER), and internal rotation (IR) strengths were measured each side using a hand-held dynamometer (Power Track II, Jtech Medical Industry) . The MV of deltoid muscle was significantly larger value on the dominant side (DOM) than on the non-dominant side (NDOM) in both the PG and CG groups (p<0.05) . However, no significant differences in the MV of the rotator cuff muscles and the measured shoulder strength (ABD, ER, and IR) were observed between both sides in either group. Similarly, no significant differences in the DOM/NDOM ratio of the muscle volume and the measured shoulder strength were observed between the two groups. These results suggest that the rotator cuff muscle volume and strength does not differ in both sides of the PG, and DOM/NDOM ratios of the rotator cuff muscle volume and strength of the PG does not differ in those of the CG.

Hyperextension Overload Syndrome of the Elbow in Baseball Pichers / 대한정형외과학회잡지

Some baseball pichers have the symptom-complex of the elbow joint due to repetitive throwing. The Hyperextension overload syndrome is symptom-complex caused by impingement between olecranon tip and fossa during hyperextension of the elbow. The patients of hyperextension overload syndrome is have some pathology of his elbow such as bony spur on olecranon tip, intra-articular loose body or degenerative arthritis. And they complaint of pain or limitation of extension. The authors diagnosed and treated five cases of hyperextension overload syndrome. All of them had flexion contracture. Three cases of them had cubitus valgus. But no had medial instability of the elbow. Three cases of them had tenderness on the olecranon tip. Four patients treated by excision of osteophyte or loose body with arthroscopic or open operative technique.