Table 2 Differences in rotational angles during stance, load, foot contact, pre-swing, and ball contact
From: Longitudinal changes in youth baseball batting based on body rotation and separation
Variables | Group 1 (N = 17) | Group 2 (N = 13) | ||||||
|---|---|---|---|---|---|---|---|---|
U8a | U9b | U10c | ES | U11a | U12 b | U13 c | ES | |
Stance | ||||||||
Head rotation | 26.7 ± 4.7 | 25.7 ± 3.4 | 23.1 ± 5.4 | 0.189 | 26.5 ± 5.6 | 26.9 ± 5.4 | 26.7 ± 3.3 | 0.004 |
Upper trunk rotation | -36.2 ± 5.2 | -32.7 ± 6.2* | -38.7 ± 9.4† | 0.205 | -36.8 ± 5.5 | -34.9 ± 9.2 | -34.6 ± 7.8 | 0.041 |
Pelvis rotation | -17.5 ± 7.4 | -7.6 ± 4.9* | -18.1 ± 11.6† | 0.417 | -27.7 ± 11.1 | -18.8 ± 9.8* | -16.5 ± 12.8* | 0.537 |
Arm direction | -51.8 ± 4.6 | -47.7 ± 5.6* | -52.6 ± 14.0 | 0.099 | -55.0 ± 7.2 | -48.0 ± 8.4* | -49.6 ± 7.6 | 0.498 |
Load | ||||||||
Head rotation | 24.3 ± 3.7 | 25.8 ± 3.4 | 20.3 ± 10.4 | 0.191 | 28.5 ± 6.4 | 26.8 ± 5.8 | 27.3 ± 3.0 | 0.041 |
Upper trunk rotation | -26.6 ± 4.1 | -30.9 ± 6.2* | -41.1 ± 13.9*† | 0.790 | -49.7 ± 10.4 | -36.8 ± 9.9* | -33.9 ± 8.2* | 0.563 |
Pelvis rotation | -14.6 ± 6.1 | -15.1 ± 6.3 | -28.6 ± 17.7*† | 0.381 | -38.6 ± 8.6 | -22.3 ± 10.4* | -17.8 ± 13.1*† | 0.714 |
Arm direction | -51.0 ± 4.6 | -51.0 ± 5.6* | -57.5 ± 21.4 | 0.163 | -61.6 ± 6.3 | -59.7 ± 3.0 | -60.8 ± 4.7 | 0.043 |
Foot contact | ||||||||
Head rotation | 26.9 ± 4.8 | 25.9 ± 3.4 | 21.5 ± 8.1 | 0.294 | 29.7 ± 4.7 | 27.3 ± 5.2 | 27.8 ± 4.4 | 0.074 |
Upper trunk rotation | -5.1 ± 3.5 | -16.0 ± 3.9* | -25.6 ± 6.8*† | 0.871 | -29.9 ± 5.1 | -38.3 ± 10.4* | -40.6 ± 6.5* | 0.497 |
Pelvis rotation | -10.4 ± 5.7 | -19.8 ± 3.3* | -33.4 ± 6.5*† | 0.896 | -35.3 ± 8.3 | -23.0 ± 9.4* | -16.5 ± 8.2* | 0.699 |
Arm direction | -43.2 ± 5.0 | -45.6 ± 4.8 | -48.3 ± 8.0 | 0.139 | -56.3 ± 4.7 | -61.9 ± 3.3* | -63.8 ± 5.7* | 0.526 |
Pre-swing | ||||||||
Head rotation | 27.1 ± 4.8 | 26.0 ± 3.5 | 26.1 ± 6.1 | 0.016 | 30.3 ± 5.9 | 30.6 ± 3.7 | 32.3 ± 4.4 | 0.068 |
Upper trunk rotation | 51.4 ± 6.5 | 51.6 ± 10.2 | 45.0 ± 7.4* | 0.221 | 35.9 ± 6.6 | 29.3 ± 4.7* | 26.2 ± 3.3*† | 0.712 |
Pelvis rotation | 45.4 ± 5.9 | 46.5 ± 7.9 | 39.3 ± 5.0*† | 0.381 | 29.7 ± 5.5 | 31.7 ± 10.1 | 30.8 ± 4.7 | 0.023 |
Arm direction | 11.0 ± 3.4 | 12.7 ± 4.4 | 4.9 ± 4.4*† | 0.498 | -6.0 ± 3.3 | -5.1 ± 1.8 | -12.6 ± 6.2*† | 0.529 |
Ball contact | ||||||||
Head rotation | 27.9 ± 4.0 | 26.1 ± 3.5 | 29.0 ± 7.2 | 0.070 | 33.8 ± 7.9 | 31.0 ± 3.4 | 30.8 ± 7.5 | 0.088 |
Upper trunk rotation | 80.9 ± 3.3 | 79.2 ± 2.4 | 75.5 ± 3.1*† | 0.478 | 73.5 ± 5.2 | 74.3 ± 2.2 | 73.4 ± 2.4 | 0.022 |
Pelvis rotation | 81.4 ± 3.2 | 80.4 ± 2.9 | 79.8 ± 3.4 | 0.078 | 79.8 ± 5.5 | 81.5 ± 4.1 | 81.5 ± 2.3 | 0.061 |
Arm direction | 80.7 ± 3.7 | 75.7 ± 4.0* | 71.7 ± 4.3* | 0.539 | 71.1 ± 3.8 | 69.6 ± 2.5 | 69.4 ± 2.5 | 0.107 |