肩關節肌肉在進行閉鎖式活動之肌電學分析探討

EMG Analyses of Shoulder Muscles during Closed Chain Activities

過去的研究大多著重在開放鏈運動(open kinetic chain exercises),所以對於上肢的閉鎖鏈運動(closed kinetic chain exercises)並沒有足夠的資訊,然而閉鎖式運動相對於開放式運動在恢復初期是比較安全的,因此本實驗的目的在於分析及比較不同的閉鎖鏈運動的肌電學資料,探討當肩關節(shoulder joint)進行承重運動時的肌電圖(EMG)。
方法:共二十位男性受試者參與本實驗,藉由控制數種因子來讓受試者進行不同的閉鎖鏈運動訓練,包括不同姿勢,支撐點改變及不同肩關節位置,來產生不一樣的閉鎖鏈運動,每一個受試者執行運動時直接在力板,同時保持手腳或手膝蓋支持姿勢,並合併四點、三點、斜向或單邊支撐,並會要求受試者將身體往前後左右平移到不同的位置。量測因子包括肩關節角度及肩肌肉的肌電反應。
結果:根據實驗結果,伏地挺身以腳著地(hands and knees)都比伏地挺身以膝著地(hands and knees)要造成較高的 EMG 活動,對於肩屈肌(flexor)及肩胛肌群(scapular muscle)在斜向支撐時有最高的 EMG 活動,而其他大部分的肩膀肌群在單邊支撐時有最大的活動(P 值 <0.05),且在身體往前(肩關節伸直動作extension)及身體往右(肩關節水平內收 horizontal adduction)位置時會有最大的肌肉活動。不同的姿勢及支撐方法是最主要影響的因子,所以使用伏地挺身以腳著地(hands and knees)合併根據不同肌肉,選擇斜向或單側支撐,會產生有最大的肌肉活動及肩關節作用力。
結論:所以在實驗中獲得有關上肢的閉鎖鏈運動訓練的 EMG 活動訊息對於物理治療師是有用的,可以合併過去對於開放鏈運動訓練的資料來設計由易到難,且對病人最適合的運動計畫。

Background: Previous studies of shoulder muscle strengthening and reha-bilitation have emphasized the use of open kinetic chain exercises, but closedkinetic chain exercises are safer than open kinetic chain exercises. However,there is limited information on closed kinetic chain exercises for the upperextremities. The purpose of this study was to analyze and compare kinetic and electromyographic (EMG) data during closed kinetic chain exercises, in order to explore the kinetic characteristics and EMG data of shoulder weight-bearing exercises. Method: Twenty male subjects participated in the study. They performed different shoulder weight-bearing exercises by controlling several factors, including posture, support, and position. Each subject performed exercises directlybearing on a force plate or foam, in hands-and-knees or hands-and-feet posturescombined four point, three point, diagonal, or unilateral support. Then each subject was asked to shift his body forward, backward, leftward, and rightward to different positions. Outcome measures were the angle of the shoulder joint, and EMG activities of the shoulder muscles. Result: For all outcome measures, the hands-and-feet posture was significantly higher than the hands-and-knees posture(p value < 0.05). The shoulder flexor and scapular upward rotator had the highest EMG firing under diagonal support (p value < 0.05), but other shoulder muscles had the highest EMG firing under unilateral support (p value < 0.05). However ,the hands-and-feet posture could enhance the difference between different supporting methods. The extension and horizontal adduction positions result edin the highest EMG activities. The posture and support were the primary factors influencing the shoulder muscle EMG activities. The hands-and-feet posture combining diagonal support or unilateral support for different muscles resulted in the highest muscle loading, and shoulder loading. Conclusion: The information about muscle activities during shoulder weight-bearing exercises is useful for physical therapists when combining open kinetic chain exercises to design appropriate exercise programs for patients.