Tackler head placements during contact are associated with the tackler-related concussion occurrence
| Head placements (vs no injuries) | OR | (95% CI) | P value |
| Correct | Reference | ||
| Incorrect* | 8.21 | (3.73 to 18.11) | <0.01 |
| Correct | Reference | ||
| Incorrect (1)† | 14.78 | (6.27 to 34.84) | <0.01 |
| Incorrect (2)‡ | 3.83 | (1.38 to 10.64) | 0.01 |
*An incorrect head placement as satisfying either (1) when the tackler’s head was in front of the ball-carrier or (2) when any tackles gave an impact force to the tackler’s head in the diagonal, lateral or posterior direction.
†An incorrect head placement as satisfying (1) when the tackler’s head was in front of the ball-carrier.
‡An incorrect head placement as satisfying (2) when any tackles gave an impact force to the tackler’s head contacting from the diagonal, lateral or posterior direction.
CI, confidence intervals; OR, odds ratio.