著者

中村 真里 中村 康雄 林 豊彦 福田 登 駒井 正彦 橋本 淳 信原 克哉 Chao Edmund Y.

出版者

バイオメカニズム学会

雑誌

バイオメカニズム (ISSN:13487116)

巻号頁・発行日

no.16, pp.13-25, 2002-06-25

被引用文献数

9 4

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Baseball pitching involves a complicated and rapid movement that has been investigated to prevent injuries and to improve the pitching performance. It is difficult to assess the pitching motion with high accuracy and a high sampling rate, due to the limitations of preexistent camera systems. The current camera system, however, has enough capacity to measure pitching motions with high accuracy and a high sampling rate. We have been diagnosing shoulder joint injuries caused by pitching. The patients (N=939) felt pain during the pitching sequence as follows: top position (32.5%), maximum external rotation (27.2%), and ball release (14.5%). Hence the top position is one of the most important postures to investigate the mechanisms of shoulder joint injury in pitchers. There have been no studies that focused on the top position, however. The main purpose of this study was to develop a system to assess the pitching motion accurately. Another purpose was to estimate the instant of the top position and evaluate the kinematics of the shoulder and elbow joints. Pitching movement was assessed using a motion capture system (ProReflex MCU500, Qualisys Inc., Sweden) in a studio that has an official pitcher's mound and home base. This system can record the positions of reflective markers at 500 Hz using seven CCD cameras. Thirty-two markers were mounted on the joints and body landmarks of each subject. Two markers were mounted on the ball. The pitching motions of eleven subjects were assessed, after a period for warm up. Kinematics parameters were calculated using three-axis gyroscopic Euler angle. The instant of the top position was observed for all subjects before the lead foot touched the ground. The interval from the top position to ball release was 0.242±0.0438 [s] (n=11). The subjects were divided into two groups by the type of posture at the instant of the top position, as follows: internal rotation group (n=5), 11.8±6.08 degrees, and external rotation group (n=6), 38.1±19.97. Other kinematics parameters at the top position were adduction of the shoulder at 74.2±19.84 degrees, horizontal adduction of the shoulder at 37.3±14.10 degrees, and extension of the elbow at 92.1±21.63 degrees. The timing and posture of the estimated top position were almost the same as those of the conventional top position. From the top position to lead foot contact on the pitching sequence, there were three patterns of elbow leading. The three patterns did not depend upon experience. We interpreted them as individual variations.

著者

建道 寿教 橋本 淳 橋本 卓 駒井 正彦 中村 真里 信原 克哉 中村 康雄

出版者

Japan Shoulder Society

雑誌

肩関節 (ISSN:09104461)

巻号頁・発行日

vol.28, no.3, pp.427-431, 2004

被引用文献数

2

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The Purpose of this study was to analyze the articular contact pattern of the normal glenohumeral joint. There are few previous papers concerning the dynamic contact patterns, although the studies of using the cadaver or the tracking device have been reported. The subjects consisted of 10 normal volunteers. The subjects were fixed on a tilted stand with free motion around the scapula.3D MRI images were extracted at the scapular plane at every 30° between 30° and 150° in the supine position. The images obtained at each position were transmitted to a personal computer and the description of the bony frame by digitizing methods using the analyzing software were developed. Three dimensional reconstruction of the glenohumeral joint were performed. The items of measurement were the following (1)The contact area; the distances between the humeral head and the glenoid surface were calculated and the distribution set at the distances were considered to be the contact area. The shortest distance was regarded as the proximity of the joint. The change of the center of the distribution was investigated. (2)The center of the humeral head (3) Kinematics of the humerus; (from the aspect of the scapula) Results: (1)In the contact area; the minimum contact area had shifted superiorly up to 90 or 120° elevation, but after 120° it shifted inferiorly. Concerning the antero-posterior direction of the glenoid, it shifted antero-inferiorly at the elevated position compared to that of the 30Thlevation. (2)In the center of the humeral head; it shifted superiorly at 120° or 150° compaired to the 30° elevation. Its change was within 3mm. (3)In the Kinematics of the humerus; although the glenohumeral movement was totally 66°, it was only 17' after 90° elevation. We conclude that although the contact area shifted superior until 90°, it shifted to the central part of the glenoid over 120°, because the centripetal force might have worked at the elevated position. The distribution of the contact area was assumed to be reflected as a result of seeking a good congruity of the humeral head and the glenoid.

著者

瀧澤 哲也 中村 康雄 林 豊彦 駒井 正彦 信原 克哉

出版者

一般社団法人電子情報通信学会

雑誌

電子情報通信学会技術研究報告. MBE, MEとバイオサイバネティックス (ISSN:09135685)

巻号頁・発行日

vol.106, no.592, pp.1-4, 2007-03-09

参考文献数

6

被引用文献数

3

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子供,大人を問わず野球投手は,肩・肘に障害を起こしやすい.一般的に,子供の投球障害は,身体が未発達である成長期におけるオーバーユースが主な原因と考えられている.これまでに臨床報告は数多くされてきたが,子供の投球動作を定量的に評価した報告は少ない.そのため,子供への指導や障害の予防は,経験や感覚に基づくものだった.したがって,子供の投球動作の定量的な評価が求められている.そこで本研究は,子供と大人の投球動作を定量評価して,比較・検討することを目的とする.子供45名,大人22名の投球動作を測定し,動力学的・運動学的に解析した.その結果,子供は上半身が前方へ先行する.規格化したモーメントの値は子供と大人でほぼ同等であることが示された.結果から,子供の投球障害を軽減するには,1)体幹・下半身を鍛える,2)球種や投球数を制限する,の2点が重要であると考えられる.