Table 2. Muscle activities (% maximum voluntary contraction) during isometric shoulder external rotation at various shoulder elevation angles.
| Shoulder elevation angles in the scapular plane | ||||
|---|---|---|---|---|
| 0° | 45° | 90° | 135° | |
| Infraspinatus | 91.6 (20.3) | 74.6 (18.9)** | 68.0 (25.0)** | 57.1 (16.8)**††§ |
| Upper trapezius | 29.0 (21.6) | 30.0 (11.5) | 35.6 (20.7) | 38.1 (20.4) |
| Middle trapezius | 56.1 (26.9) | 60.0 (29.4) | 46.8 (19.9) | 42.0 (18.3)† |
| Lower trapezius | 74.0 (29.5) | 70.5 (27.6) | 62.5 (21.8)* | 54.7 (18.6)**† |
| Serratus anterior | 23.6 (15.6) | 48.1 (15.5)** | 52.7 (21.3)** | 62.4 (22.5)**† |
Data are shown as means (standard deviation). *p < 0.05, **p < 0.01, compared with “0°”; †p < 0.05, ††p < 0.01, compared with “45°”; §p < 0.05, compared with “90°”