Head collision event (HCE) outcomes and assessment before and after additional permanent concussion substitute (APCS) implementation in the Premier League
| Outcome | Pre-APCS (n=38) | Post-APCS (n=42) | Significance |
| HCEs per 1000 athlete-hours of exposure (95% CI) | 28.79 (20.37 to 39.51) | 31.82 (22.93 to 43.01) | p=0.657 IDR=0.9048 (0.5677, 1.4377) |
| Medically assessed, No. (%) | 9 (23.7) | 9 (21.4) | p=0.545 |
| Duration of medical assessment, median (IQR), s | 81 (50) | 102 (213) | p=0.466 |
| No. signs of concussion | |||
| 1 | 2 | 2 | p=0.653 |
| 2 | 36 | 40 | |
| ≥3 | 0 | 0 | |
| Foul assessed, No. (%) | 15 (39.5) | 16 (38.1) | p=0.541 |