** 肩部動作很常見的問題
Scapulohumeral Rhythm
同上連結 https://youtu.be/kkNnc6ssbPI?t=58
First setting phase of scapula
手臂外展的前30度，肩胛骨只有很小的往內移動。
When we perform abduction, the GH-joint contributes 90-120°. The combination of scapular and humeral movement result in a maximum range of elevation of 150-180°. Also by abduction Inman et al. reported an inconsistent amount and type of scapular motion in relation to GH-motion this time during the initial 30°. In this early phase, motion occurs primarily at the GH joint, although stressing the arm may increase the scapular contribution.
It describes timing of movement at glenohumeral and scapulothoracic joint during shoulder elevation.
- First 30 degrees of shoulder elevation involves a "setting phase":
The movement is largely glenohumeral.
Scapulothoracic movement is small and inconsistent.
- And after the first 30 degrees of shoulder elevation:
The glenohumeral and scapulothoracic joints move simultaneously.
Overall 2:1 ratio of glenohumeral to scapulothoracic movement.
