Biomechanical variables recorded for 33 non-contact and indirect contact ACL injury cases analysed using systematic video analysis
| In balance | Player movement | Cutting angle | Leg loading | Horizontal speed at IC | Vertical speed at IC | Trunk rotation at IF | Foot rotation at IC | Foot strike | |
|---|---|---|---|---|---|---|---|---|---|
| Pressing | |||||||||
| 11 cases | No (n=2) Yes (n=9) | Forward (n=10) Sideways (n=1) | 0–30° (n=1) 30–90° (n=9) Stopping/>90° (n=1) | One leg (n=11) | High (n=8) Low (n=3) | Zero (n=11) | Toward uninjured leg (n=6) Neutral (n=4) Unsure (n=1) | Internal >45° (n=1) External (n=3) Neutral (n=6) Unsure (n=1) | Heel (n=7) Toe (n=1) Flat (n=1) Unsure (n=2) |
| Kicking | |||||||||
| 5 cases | No (n=5) | Forward (n=1) Backward (n=2) Sideways (n=2) | Stopping/>90° (n=2) NA (n=3) | One leg (n=4) Two legs* (n=1) | High (n=1) Low (n=4) | Zero (n=5) | Toward uninjured leg (n=2) Neutral (n=2) Unsure (n=1) | Internal >45° (n=2) External (n=1) NA (n=2) | Toe (n=3) Flat (n=1) Unsure (n=2) |
| Heading | |||||||||
| 5 cases | No (n=3) Yes (n=2) | Forward (n=1) Backward (n=1) Sideways (n=1) Downward (n=2) | 30–90° (n=1) Stopping/>90° (n=2) NA (n=2) | One leg (n=4) Two legs* (n=1) | Low (n=3) Zero (n=2) | High (n=3) Low (n=2) | Toward uninjured leg (n=2) Neutral (n=3) | Internal >45° (n=1) Neutral (n=2) NA (n=2) | Toe (n=4) Flat (n=1) |
| Other | |||||||||
| 12 cases | No (n=6) Yes (n=4) Unsure (n=2) | Forward (n=8) Sideways (n=3) Combined† (n=1) | 0–30° (n=3) 30–90° (n=3) Stopping/>90° (n=6) | One leg (n=8) Two legs* (n=3) Unsure (n=1) | High (n=8) Low (n=4) | Low (n=1) Zero (n=11) | Toward uninjured leg (n=6) Toward injured leg (n=2) Neutral (n=3) Unsure (n=1) | Internal 0–45° (n=2) Internal >45° (n=2) External (n=2) Neutral (n=3) Unsure (n=3) | Heel (n=4) Toe (n=1) Flat (n=4) Unsure (n=3) |
*Main load on injured leg.
†Player movement both forward and sideways.
ACL, anterior cruciate ligament; IC, initial contact; IF, index frame; NA, not applicable.