著者

上田 泰之 田中 洋 亀田 淳 立花 孝 信原 克哉

出版者

公益社団法人 日本理学療法士協会

雑誌

理学療法学Supplement

巻号頁・発行日

vol.2014, 2015

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【はじめに,目的】投球障害肩の治療・予防を考える上で,投球動作中の肩関節に加わる力学的ストレスを3次元的に求め,それに関連する運動学的・動力学的因子を検討することが重要である。これまで投球動作中の肩関節に加わる圧縮力については検討されているが,それ以外の前後方向・上下方向への力学的ストレスついてもそれらに関連する因子を検討する必要がある。本研究の目的は,投球動作中の肩関節に加わる圧縮力,前後方向および上下方向の力学的ストレスに影響を与える運動学的・動力学的因子について明らかにすることである。【方法】対象は次の条件を満たす中学・高校生の野球投手81名とした(年齢15.0±1.4歳,身長172.0±9.8 cm,体重63.2±9.8 kg,右63名・左18名)。1)投球動作の測定時に疼痛がない,2)肩・肘関節の手術経験がない,3)測定より6カ月以内に肩・肘関節の疼痛や障害のために投球動作を禁止された期間がない。投球動作の測定にはモーションキャプチャ・システムを用いた。解剖学的骨特徴点の皮膚上に36個の赤外光反射マーカーを貼付し,投球マウンド周辺に設置した7台の高速CCDカメラ(ProReflex MCU-500+,Qualisys Inc., Sweden)と2台のハイスピードビデオカメラ(HSV500C³,nac Image Technology,Japan)を用いて測定を行った。運動学的・動力学的パラメータを算出するために,胸部,上腕及び前腕座標系を設定し,胸部に対する上腕座標系の回転,上腕に対する前腕座標系の回転をオイラー角で示し,それぞれを肩関節,肘関節角度とした。また,水平面上での両肩峰を結ぶベクトルV_s,両上前腸骨棘を結ぶベクトルV_pそれぞれとマウンドプレートとの成す角度を肩甲帯回旋角度,骨盤回旋角度とした。さらにV_sとV_pとの成す角度を体幹回旋角度とした。肩関節,肘関節に加わる関節間力ならびにトルクはニュートン・オイラー法を用いて推定した。統計学的解析には,SPSS 12.0J(エス・ピー・エス・エス社,日本)を使用し,ステップワイズ法による重回帰分析を行った。投球動作時の肩関節に加わる最大圧縮力,最大前方関節間力および最大上方関節間力を従属変数とした。独立変数はトップ・ポジション(TOP),非投球側足部接地(FP),肩関節最大外旋位(MER),ボール・リリース(BR)時の肩関節および肘関節の関節角度,肩甲帯回旋角度,骨盤回旋角度,体幹回旋角度,肩関節および肘関節へ加わるトルクの最大値とした。【結果】最大肩関節圧縮力を従属変数とした場合,p<0.01でありR²=0.67であった。標準偏回帰係数はBRでの肩関節水平内転角度が0.60,BRでの体幹回旋角度が-0.51,MERでの骨盤回旋角度が-0.40,最大肩関節外旋トルクが-0.33,最大肘関節外反トルクが0.31,TOPでの肩関節水平内転角度が-0.23,最大肩関節内転トルクが-0.22,BRでの肘関節屈曲角度が-0.20,FPでの体幹回旋角度が0.17であった。肩関節最大前方関節間力を従属変数とした場合,p<0.01でありR²=0.63であった。標準偏回帰係数はFPでの肩関節水平内転角度が-0.84,最大肩関節水平内転トルクが0.41,FPでの肘屈曲角度が0.25,最大肩関節外旋トルクが-0.18,最大肩関節内転トルクが-0.16であった。肩関節最大上方関節間力を従属変数とした場合,p<0.01であり,R²=0.69であった。標準偏回帰係数は最大肩関節外転トルクが0.59,FPでの肩関節内転角度が0.55,FPでの肩関節外旋角度が-0.51,TOPでの肩関節内転角度が-0.36,BRでの肩関節内転角度が0.32,FPでの肘関節屈曲角度が0.32,FPでの骨盤回旋角度が-0.20,最大肩関節外旋トルクが-0.19,BRでの肩関節外旋角度が0.14であった。【考察】投球動作時に加わる力学的ストレスに影響する因子は,そのストレスの加わる方向により異なることが示された。肩関節の圧縮力にはBRでの肩関節水平内転やBRでの体幹回旋角度,肩関節最大前方関節間力にはFPでの肩関節水平外転や最大肩関節水平内転トルク,肩関節上方関節間力には,最大肩関節外転トルクやFPでの肩関節内転角度が影響を与える因子であった。また,それぞれの肩関節に加わるストレスに影響する因子として,FPでの肩・肘関節の関節角度が挙げられることから,この時点での投球動作に着目することは肩関節に加わる力学的ストレスを軽減させるために重要であることが定量的に確認された。【理学療法学研究としての意義】本研究の結果は,投球障害肩の疼痛部位や病態に応じた理学療法の一助となると考える。また,投球動作を詳細に分析することで,今後起こりうる投球障害肩を予測し,予防するためにも有用である。

著者

宇田 宙照 福島 充也 後藤 康夫 池田 均 塚西 茂昭 信原 克哉

出版者

日本肩関節学会

雑誌

肩関節 (ISSN:09104461)

巻号頁・発行日

vol.13, no.1, pp.11-15, 1989-11-01 (Released:2012-11-20)

参考文献数

3

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The clavicular movement during active elevation of the upper limb was analyzed in this study. Sixty right shoulders in normal sugjects were investigated by using “ Chneradiography” and the “ personal image analysis system”. The lateral lower margin and the conoid tubercle of the clavicle were measured as the points which demonstrate clavicular movement.During elevation of the upper limb in the scapular plane, the elevated ang l e s of the clavicle were calculated with the scapular movement in the following stages; “ setting phase”, the “ hanging joint” prase, “ transit zone”, and the “ joint needing support” phase.The results were as follows:1. The elevated angles of the clavicle increased gradually during elevation of the upper limb. Finally the average of maximum elevated angles of the clavicle was 41.5 degrees at 150degrees of the arm-trunk angle. We noticed the clavicular movement for every 10 degrees was uneven in this study.2. No remarkab l e elevation was noted in the “ setting phase”. The elevated angles of the clavicle reached 4.22 degrees during the setting phase. Clavicular movement is similar to scapular movement, however, it was slightly irregular and unstable.3. In the “ hanging joint” phase, the elevated angle of the clavicle was 3.69 degrees forevery 10 degrees.4. In “ transit zone”, the elevated angle of the clavicle was 4.02 degrees for every 10degrees. The ratio of clavicular movement was closest to the scapular movement in this phase. And this movement was the most characteristic.5. In the final stage, in the “ joint needing support” phase, the elevated angle of the clavicle increased 4.22 degrees of the elevation of the upper limb.6. The absolute relationship between scapular and clavicu l a r movements were obtained from these results.

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

上田 泰之 田中 洋 亀田 淳 立花 孝 乾 浩明 信原 克哉

出版者

公益社団法人日本理学療法士協会

雑誌

理学療法学 (ISSN:02893770)

巻号頁・発行日

vol.44, no.2, pp.101-108, 2017 (Released:2017-04-20)

参考文献数

28

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【目的】投球動作中の肩関節離開力,前後および上下方向の力学的ストレスに影響を与える因子を明らかにすること。【方法】対象は野球選手81 名。肩関節最大離開力・前方・上方関節間力を従属変数とし,肩関節,体幹,骨盤に関する因子27 個を独立変数とした重回帰分析を行った。【結果】肩関節離開力を従属変数とした場合,ボール・リリースでの肩関節水平内転角度,体幹回旋角度など6 個の因子が選択された。肩関節前方関節間力を従属変数とした場合,非投球側足部接地での肩関節水平外転角度と肩関節水平外転トルクの因子が選ばれた。肩関節上方関節間力を従属変数とした場合,肩関節最大外旋位での肩関節外旋トルク,ボール・リリースでの肩関節外転トルクなど7 個の因子が選択された。【結論】肩関節離開力に影響する因子は報告されていたが,本研究では肩関節前方・上方関節間力についても検討した。その結果各々の力学的ストレスに対し影響する因子は異なることが示された。

著者

橋本 卓 金谷 整亮 池田 均 塚西 茂昭 信原 克哉 田中 道夫

出版者

日本肩関節学会

雑誌

肩関節 (ISSN:09104461)

巻号頁・発行日

vol.14, no.2, pp.245-248, 1990-09-01 (Released:2012-11-20)

参考文献数

4

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We have measured the intra-articular pressure simultaneously with arthrography of the shoulder. In this study, changes in the intra-articular pressure were examined in unstable shoudlers associated with loose shoulder, rotator interval lesion, and traumatic recurrent anterior dislocaiton.Of the 731 shoulders (731 patients) in which intra-articular pressure was me a sured from 1981, the measurement was possible in 254 shoulders (254 patients). A total of 91 shoulders, consisting of 20shoulders with traumatic recurrent anterior dislocation,40 loose shoulders, and 31 shoulders with rotator interval lesion, were evaluated.Physiologic saline was in f used into the joint, and canges in the intra-articular pressure were recorded as electric signals through a transducer. The arm was moved up and down passively, and the pressure was measured at intervals of 10.In loose shoulder and rotator interval l e sion, the intra-articular pressure decreased as the arm was lifted higher, but the decreases were smaller than in normal shoulders. In these groups, there was a smaller pressure increase to the position of maximum uplift with a smaller peak value and within a narrower range than in the normal group. These findings were more notable in the shoulders with an FSH angle of 81' or greater. These results suggest that the intra-articular pressure reflects the joint capacity.In traumatic recurrent anterior dislocation, however, the decrease in the pressure in an early stage of arm lifting was the greatest among all groups including the normal group, and the pressure increase with arm lifting was gentler in shoulders with an FSH of 80 °or less, unlike in the other two groups.The changes in the intra-articular pressure in shoulders with traumatic recurrent anterior dislocation may be explained by disruption of the anterior capsular mechanism and muscle contraction due to anxiety over the possibility of dislocaiton during arm lifting as well as the looseness of the articular capsule.

著者

信原 克哉

出版者

西日本整形・災害外科学会

雑誌

整形外科と災害外科 (ISSN:00371033)

巻号頁・発行日

vol.23, no.4, pp.514-517, 1974

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Although the recent literature abounds with explanations for rotator cuff injury and its diagnosis, there do not appear to be consistent observations concerning a well established treatment regimen. Many observations and questions have arisen which concern such matters as ability of the rotator cuff to heal and the relationship of rotator cuff pathology to its etiology. These statements generally indicate that rotator cuff injury is usually caused by trauma to a prevously degenerated tendon. More important than this matter, however, is the idea that treatment by suture alone is not enough. A coherent program including immobilization of the upper limb and other postoperative measures is essential. In this connection, an important consideration in the recovery of glenohumeral motion is that the fundamental function of the rotator cuff may be one of guiding the movement of the greater tubercle.

著者

三森 甲宇 中川 照彦 古屋 光太郎 信原 克哉

出版者

Japan Shoulder Society

雑誌

肩関節 (ISSN:09104461)

巻号頁・発行日

vol.18, no.2, pp.313-317, 1994

被引用文献数

2

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(Purpose) Voluntary dislocation of the tendon of the long head of the biceps is extremely rare. Here we will report on this dislocation in one patient.<br>(Patient) The Patient, a 37-year-old male fell down with his arm extended. Since then, he had a click and pain of the shoulder when he elevated his arm. When he had contracted his biceps with his arm extended and internally rotated, the tendon of the long head of the biceps dislocated from the bicipital groove. By elevating the arm 135 degrees from that position, the tendon reposited with a click and pain. Arthrography showed a dislocation of the tendon of the long head of the biceps. Arthroscopy and a tenodesis of the biceps tendon were performed.<br>(Conclusion) When observing the shoulder joint of a cadaver, the insertion of the subscapularis tendon was separated into two layers. One was a superficial layer, the other a deep one. Some parts of the superficial layer formed the transverse ligament. So we believe that the tendon of the long head of the biceps is often dislocated accompanying with a tear of the subscapularis tendon.

著者

乾 浩明 町田 明敏 橋本 淳 信原 克哉

出版者

Japan Shoulder Society

雑誌

肩関節 (ISSN:09104461)

巻号頁・発行日

vol.25, no.3, pp.471-474, 2001

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This study examines the glenoid cavity using three-dimensional MRI. Forty volunteers were enrolled in the study. Three-dimensional scapular images were reconstructed using an open MRI and computer software. The tilting angles of the glenoid bone were measured in five consecutive axial planes perpendicular to the glenoidal long axis. Cross sections were divided into three types (concave, flat, and convex)according to the shape on each plane.<BR>The average tilting angles for the five planes from the bottom to the top were 3.3&plusmn;4.1,1.4&plusmn;3.8, -0.6&plusmn;1.9, -1.4&plusmn;3.3, -6.2&plusmn;3.3 degrees anteriorly, indicating that the three-dimensional bony structure of the glenoid was twisted anteriorly to posteriorly. Images on the bottom plane consisted of 82.5% concave type,15% flat type, and 2.5% convex type, while only 3 cases (7.5%) showed a concave shape in the top plane. The shape of the glenoid cavity is thought to be conducive for glenohumeral motion and stability.

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&deg; between 30&deg; and 150&deg; 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&deg; elevation, but after 120&deg; 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&deg; or 150&deg; compaired to the 30&deg; elevation. Its change was within 3mm. (3)In the Kinematics of the humerus; although the glenohumeral movement was totally 66&deg;, it was only 17' after 90&deg; elevation. We conclude that although the contact area shifted superior until 90&deg;, it shifted to the central part of the glenoid over 120&deg;, 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.

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

大井 雄紀 高木 陽平 土山 耕南 乾 浩明 信原 克哉 吉矢 晋一

出版者

日本肩関節学会

雑誌

肩関節 (ISSN:09104461)

巻号頁・発行日

vol.40, no.2, pp.675-677, 2016

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Stride Foot Contact(SFC)における骨盤回旋,体幹と股関節の姿勢に注目し,年代別に運動学的検討をすることを目的とした.対象は野球投手287名:小学生(小)42名,中学生(中)94名,高校生(高)105名,コントロール群(コ)46名(19歳以上かつ球速120km/h以上)とした.対象者の投球動作をモーションキャプチャ・システムによりデジタル化した.大腿,腰部,体幹部に座標系を設定し,それぞれの座標系の回転をオイラー角で表した.全ての年代において,SFCの骨盤左回旋角度と相関関係がみられた変数は,それぞれ体幹左側屈角度(r = 0.5以上),右股関節内転角度(r = 0.49以上),右股関節伸展角度(r = 0.78以上),左股関節内転角度(r = 0.46以上),左股関節屈曲角度(r = 0.43以上)であった.骨盤が早期回旋しないよう体幹側屈,股関節屈曲伸展,内転に注目しながら投球指導を行う必要があると言える.

著者

春名 匡史 板野 哲也 立花 孝 田中 洋 信原 克哉

出版者

公益社団法人 日本理学療法士協会

雑誌

理学療法学Supplement

巻号頁・発行日

vol.2015, 2016

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【はじめに,目的】Wind-up期である,踏み出し脚の膝が最も高く挙がった時点(以下KHP:Knee Highest Position)における体幹アライメントや身体重心位置が,early cocking期である踏み出し脚接地時(以下FP:Foot Plant)に影響を及ぼすといった報告が散見される。しかし,この点を定量的に検討した報告はほとんど見当たらない。そこで今回,KHPにおける体幹アライメント・身体重心位置が,FPの体幹アライメントに実際に影響を与えるか否かを定量的に検討した為報告する。【方法】対象は,踏み出し脚の膝を軸脚側の上前腸骨棘より挙上して投球を行った様々な競技レベルの野球選手55名とした(年齢9-30歳)。左投手は右投手に変換して分析を行った(以下左右は右投手を想定して記載する)。KHPにおける上半身重心位置,骨盤左回旋・後傾角度,体幹伸展・右側屈角度の5つの変数群と,FPの骨盤左回旋角度,体幹伸展・右側屈角度の3つの変数群に対し,正準相関分析を行った。なお,重心位置と体幹・骨盤角度では単位が異なる為,変数は標準化を行った。上半身重心位置は合成重心法により算出した点の,水平面上における軸脚足部長軸方向の位置を,つま先方向を正として求め,軸脚足部長軸の長さで規格化した。骨盤運動はカメラ座標系に対する骨盤座標系の回転を,体幹運動は骨盤座標系に対する胸部座標系の回転をそれぞれオイラー角で表現した。有意水準は5%とした。【結果】正準相関分析の結果,第1正準変量では,正準相関係数がr=0.656(p=0.002)で,正準負荷量は,KHPの変数群では上半身重心=-0.017,骨盤左回旋=0.518,骨盤後傾=-0.915,体幹伸展=0.963,体幹右側屈=0.007であり,FPの変数群では骨盤左回旋=0.072,体幹伸展=0.914,体幹右側屈=-0.268であった。KHPの体幹屈曲伸展,骨盤前後傾,骨盤回旋,上半身重心,体幹側屈の順に,FPにおける体幹伸展への影響度が高かった。第2正準変量以下は正準相関係数が有意でなかった。【結論】本検討の結果より,KHPにおいて体幹がより伸展位,骨盤がより前傾位であると,FPの体幹伸展が大きくなると考えられた。しかし,有意な正準相関係数が認められ,正準負荷量が高値であったものは,FPの変数群では体幹伸展のみであった。FPでの不良動作として頻繁に述べられる,「体の開き」を表すと考えられるFP骨盤左回旋等は,KHPによる有意な影響はみられなかった。つまり,KHPによるFPへの影響は,定量的には限定的であった。この為,実際の臨床において,KHPの影響によりFPの不良な体幹アライメントが生じていると考える時は,慎重な検討が必要である。

著者

中村 康雄 林 豊彦 中村 真里 建道 寿教 信原 克哉 菊入 大輔 桐生 慎哉

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

vol.17, pp.111-121, 2004 (Released:2005-04-15)

参考文献数

17

被引用文献数

1 1 2

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Diagnosis of a shoulder joint injury, particularly one brought about during sports activities, necessitates measurement of its motion accurately and noninvasively. Conventional measurement of shoulder joint movement, however, deals solely with relative movement between humerus and thorax, neglecting other components of the joint. We have focused on 6-DOF measurement of scapula movement relative to the thorax, a subdominant component of shoulder movement. Such motion data, however, cannot easily be obtained by means of a marker-based motion-capture system, due to the skin mobility relative to the skeleton. The objective of this study was to validate measurement accuracy of scapula movement when measuring markers are attached to the skin above the scapula’s bony landmarks.We employed an open MRI (Magnetom Open, Siemens, Germany) to measure the shoulder joint and markers attached to the subject’s skin. Five and three markers were attached to the skin above the scapula and thorax, respectively. Three volunteers (24.0±2.64 years old), who possessed no distinct kinetic dysfunctions in their shoulders, served as subjects, in this preliminary study. Their shoulder movements were sampled at three humeral elevation angles (0°, 90°, 150°) on a frontal plane by open MRI. In order to reduce the skin mobility, the same movements were recorded, using a more accurate method in which the scapula’s markers were relocated into correct positions, determined through the palpation of an experienced physical therapist, at each humeral elevation. In an attempt to validate the skin mobility, we measured the deviation of the markers from the scapula’s bony landmarks during humeral elevation. Next, the scapula movements were estimated by two different methods as follows: the registration technique using bony shape and the least squares method using the set of markers.The results demonstrated that the deviation of the markers could be reduced into less than or equal to 19.0 mm if the markers were remounted at each elevation angle. Using the remounted markers, we verified the estimated error of position and orientation of the scapula to lie within 10.1° and 6.4 mm, respectively.In conclusion, we validated measurement accuracy of the scapula movement using skin markers above the scapula’s bony landmarks. The results showed that a motion-capture system is capable of quantitatively measuring the static shoulder joint movement with the scapula.

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.