著者

八十島 崇 木塚 朝博 埜口 博司 白木 仁 向井 直樹 下條 仁士 宮永 豊

出版者

The Japanese Society of Physical Fitness and Sports Medicine

雑誌

体力科学 (ISSN:0039906X)

巻号頁・発行日

vol.52, no.1, pp.43-50, 2003-02-01 (Released:2010-09-30)

参考文献数

24

被引用文献数

1 2

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Electromyographic activity of the shoulder muscle at 20 and 90°abduction (20 Abd, 90 Abd) during external rotation was investigated in seven healthy men with no history of injury or instability of the shoulder joint.Electromyography (EMG) was recorded using intramuscular fine-wire electrodes inserted into the M. Supraspinatus, M. Infraspinatus and M. Teres minor, and with bipolar surface electrodes on the middle and posterior parts of M. Deltoid anti the upper and middle parts of M. Trapezius. To compare activity in different muscles, the integrated EMG (iEMG ) activity of each muscle was normalized.M. Infraspinatus and M. Teres minor showed significantly higher activity at both the 20 Abd and 90Abd compared with the middle and posterior parts of M. Deltoid and upper parts of M. Trapezius. M. Supraspinatus, the middle and posterior parts of M. Deltoid, and upper and middle parts of M. Trapezius all showed a difference in activity level between the two positions.These findings suggest that when M. Infraspinatus and M. Teres minor contribute to external rotation as a stabilizer and prime mover, consecutively, M. Supraspinatus, the middle and posterior parts of M. Deltoid, and upper and middle parts of M. Trapezius function according to the positions. Moreover, the activity of the upper and middle parts of M. Trapezius in 90Abd should influence stabilization, adduction and upward rotation of the scapula. Therefore, we conclude that the external rotation position is closely related to shoulder muscle activity and coordination.

著者

八十島 崇 木塚 朝博 埜口 博司 白木 仁 向井 直樹 宮永 豊

出版者

The Japanese Society of Physical Fitness and Sports Medicine

雑誌

体力科学 (ISSN:0039906X)

巻号頁・発行日

vol.52, no.5, pp.491-498, 2003-10-01 (Released:2010-09-30)

参考文献数

28

被引用文献数

1 1

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The purpose of this study is to identify the effect of position (full can, empty can) and change of angle on the activity of shoulder muscles during scapular plane abduction ; and also to examine its application to exercises used for rehabilitation of shoulder muscles. Seven healthy subjects (23.4±1.4 yr) with normal shoulder function performed scapular plane abduction with external rotation (full can) and scapular plane abduction with internal rotation (empty can) . An electromyogram was recorded with a fine wire intramuscular electrode at the supraspinatus, deltoid anterior, middle, posterior and trapezius upper with bipolar surface. The EMG activity (RMS) of each muscle was normalized by the highest EMG activity (100%RMS) during a maximum manual muscle test for each muscle (%RMS) . The %RMS of each muscle remarkably increased with a change of the angle for empty can, whereas it showed a slight increase with a change of the angle for full can. This finding suggests that the position of full can and empty can in scapular plane abduction affects the function of shoulder muscles. In addition, full can exercise is recommended in order to improve function of the supraspinatus and the muscular activity balance between the supraspinatus and the deltoid. Empty can exercise is applied to sport-specific exercise for rehabilitation of shoulder muscles.

著者

埜口 博司 落合 直之 坂根 正孝 宮永 豊

出版者

Japan Shoulder Society

雑誌

肩関節 (ISSN:09104461)

巻号頁・発行日

vol.25, no.2, pp.257-262, 2001

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[Purpose]The purpose of this study was to evaluate the activity of shoulder muscles in various shoulder positions in the external rotational motion.<BR>[Materials and methods]We examined the non-dominant side of shoulders of 8 adult males who did not have any shoulder disorder. We pasted surface electrodes for 7 outer muscles and stuck needle electrodes into 3 inner muscles of each subject. Each person performed isometric external rotation motion in various loads (0,3,9,15Nm) in 6 positions (60&deg; internal rotation, neutral,30&deg; external rotation with arm at side, and neutral,45&deg; external rotation,90&deg; external rotation with arm at 90&deg; abduction position) with a Cybex-NORM770. We obtained electromyograms of each muscle. An electromyogram signal during a maximum manual muscle strength test (MMT) was selected as the normalizing value (100%) for each subject.<BR>Each activity (%MMT) was atatistically compared, using Scheffe's test. The statistical significance was set at 0.01.<BR>[Results and conclusion]During isometric external rotation motion, in internal rotation or arm at side position, the activities of the muscles were low and the activities of the inner muscles were higher than those of the outer muscles, so these positions might be appropriate for rotator cuff exercises in the early phase of rehabilitation. While, in the 90&deg; external rotation with arm at 90&deg; abduction positi on, which is similar to the cocking phase of throwing, the activities of all the muscles including the outer muscles were very high. So we must be careful when we do shoulder exercise in such like position not to overload the shoulder muscles.