ECG changes in adolescent professional soccer players
| Mean (SD) | 5th to 95th centile range | |
| Rate (beats/min) | 64 (11) | 48 to 84 |
| P axis (degrees) | 41 (26) | −9 to +76 |
| QRS axis (degrees) | 65 (28) | +13 to +96 |
| T axis (degrees) | 33 (17) | +6 to +58 |
| PR interval (ms) | 145 (21) | 112 to 180 |
| QRS duration (ms) | 94 (8) | 84 to 108 |
| QTc duration (ms) | 402 (16) | 377 to 428 |