著者

山口 幸之助 杉田 英樹 中溝 寛之

出版者

中国・四国整形外科学会

雑誌

中国・四国整形外科学会雑誌 (ISSN:09152695)

巻号頁・発行日

vol.23, no.2, pp.323-326, 2011

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This study was conducted to verify the clinical outcomes after treatment of fracture of the hamate hook in baseball players. Nine male baseball players, who underwent resection of the hamate hook with a J-shaped skin incision from the ulnar midlateral area of the palm to the palmar side of the wrist, were included in this study. In one patient, palmaris longus tenden grafting was added because of a partial tear of the flexor digitorum profundus of the little finger. The mean patient age at the time of surgery was 19.2 years (range: 14 to 56 years), and the mean follow-up period was 3.6 months (range: 1 to 7 months). Except for the one patient with tendon grafting, eight patients made a full return to baseball in mean about 5.3 weeks. As a postoperative complication, there was numbness of the ulnar nerve area in one patient for only a short period. None of the patients had any pain in the treated hand at the time of the final examination. In cases of hamate hook fracture in baseball players, excision of the hook is useful for early return to the sport.

著者

中溝 寛之 橋本 淳 中村 真里 金谷 整亮 信原 克哉 中村 康雄

出版者

日本肩関節学会

雑誌

肩関節 (ISSN:09104461)

巻号頁・発行日

vol.28, no.2, pp.355-358, 2004-08-30 (Released:2012-11-20)

参考文献数

5

被引用文献数

1

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The purpose of this study was to investigate the characteristics of baseball pitching motion in young pitchers. Sixty-five asymptomatic pitchers were analyzed with a motion capture system. The subjects were classified into two groups according to their age: A: 34cases (10-15 years old), B: 3lcases (19-34 years old). Kinematic and kinetic parameters were used to compare the differences between the two groups. Abduction and horizontal adduction angles of the upper arm were smaller in group A at ball release. The trunk was less flexed and twisted, but was bent much more toward the non-throwing side in the group A. There were no significant differences between the two groups with regard to the elbow angles, the wrist angles and the interval from arm-cocking phase to ball release. Our results showed that the young pitchers tend to put their pitch arm behind their trunk at ball release. That position is not close to “Zero Position”. It causes stretching the anterior structure of the shoulder. Furthermore, the shoulder is overloaded by the rotational stress from the end of armcocking phase to ball release. Repetition of this stress might cause epiphyseal damage for young pitchers. The young pitchers should be taught proper pitching mechanics. Limitation on pitches might be able to reduce the risk of epiphyseal damage in young pitchers.

著者

中村 康雄 林 豊彦 中村 真理 中溝 寛之 信原 克哉 加藤 直 飯塚 大輔

出版者

バイオメカニズム学会

雑誌

バイオメカニズム

巻号頁・発行日

vol.17, pp.123-132, 2004-08-25

参考文献数

21

被引用文献数

4

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The shoulder and elbow joint of a baseball pitcher are frequently overused by the repetition of throwing. The overuse causes throwing injuries of the shoulder or the elbow joint. To prevent the injuries or find them as soon as possible at an early stage, it is important to understand and evaluate each individual's baseball pitching motion exactly. Therefore, we are developing an analysis system of the baseball pitching motion for clinical use. The pitching motion is classified into four major pitch styles, as follows: overhand, three-quarter, sidearm, and underhand. In the long-term clinical experience in Nobuhara Hospital, we have expected that one of the causes of throwing injuries is related to the pitch styles. A previous paper reported that different pitch styles produced different kinematic and kinetic results of pitching motion analysis (Matsuo, 2000). The difference of pitch styles will influence analysis results of the pitching motion. The classification, however, was performed qualitatively by a person having baseball experience. There is no standard method to classify the pitch styles quantitatively. The pitch styles also have to be classified quantitatively in order to investigate various factors of injuries. The aim of this study was to classify baseball pitchers of various levels into four pitch styles quantitatively and compare the kinematic and kinetic parameters. We measured the pitching motions of the baseball pitchers, using a motion-capture system at 500 Hz. Ages of the 104 subjects of this experiment ranged from 10 to 38 years. We suggested four kinematic parameters in order to classify the pitch styles. The measured pitching motions were then classified into four pitch styles, using multivariate discriminant analysis. The correct answer rate was 89.4%. ANOVA revealed significant differences of the antero-posterior direction of resultant force at the time of ball release among four classified pitch styles. The A-P force vector had high correlation (r=0.82) with horizontal adduction angle of the upper arm. The shear force on the shoulder is one of causes of injury during pitching. To reduce the risk of shoulder injuries, we believe it is necessary to reduce shear forces on the pitcher's shoulder. Our results showed that the sidearm group had 50% lower shear force than the other groups. In conclusion, we suggested four kinematic parameters in order to classify the pitch styles. This result shows that these parameters are appropriate for classifying the pitch styles without relation to age or skill differences. The results of kinematic and kinetic parameters showed the significant differences between four pitch styles. Our next task is to increase the number of subjects, especially sidearm and underhand pitchers.