0). Contact to the ‘head/face’ of the concussed player was noted in all injury events (n=10). In contrast, the body region of the other player most commonly contacted in concussion events was ‘hips and below’ (50%, n=10).
Seventy per cent of concussions occurred as a result of contact to the ‘anterior’ side of the head, with 20% as a result of contact to the ‘posterior’ side of the head (1 body location unidentifiable, n=10). Acceleration of the head was found to occur within the ‘sagittal’ plane 50% of the time. Only 20% of the concussed players were moving at a ‘fast’ speed preceding the concussion. The majority (70%, n=10) of injured players were either ‘stationary’ (50%) or moving at a pace categorised as ‘slow’ (20%). In contrast, the ‘other’ players involved in the inciting event were moving at a ‘moderate’ (60%, n=10) and ‘fast’ (40%) pace.
Injury and non-injury playing situations
Sixty per cent (n=10) of injury events occurred in the ‘fourth quarter’, whereas non-injury events were more evenly distributed between quarters with 45%, 24%, 19% and 12% occurring in the first, second, third and fourth quarters, respectively (n=83). Two of the four injurious rucks (50%) occurred in the ‘defensive in-goal area/try-line to defensive 22 m’, whereas the majority (53%, n=60) of non-injury rucks occurred in the ‘defensive half-way line to defensive 22 m’. All (n=4) aerial collision situations (injury and non-injury) occurred within the ‘ball-carriers 22 m to the half-way line’. Two injurious tackles occurred within the ‘ball-carrier's 22 m to the half way line’ and two were within the ‘defensive half-way line to defensive 22 m’, with the remaining one occurring in the ‘defensive in-goal area/try-line to defensive 22 m’ (n=5). The majority (42%) of non-injury tackles occurred in the ‘defensive half-way line to defensive 22 m’ (n=19).
Tackle descriptors for injury and non-injury events
The body position of the tackler in injury events was distributed as follows: 20% ‘upright’, 20% ‘medium’, 20% ‘low’, 20% ‘upright to low’, 20% ‘medium to low’ (n=5; table 4). The head position of the tackler in 60% (n=5) of injury situations was ‘up and forward’ (20% ‘down’, 20% ‘tracking’). The speed of the tackler was observed as ‘slow’ in 60% (n=5) of injurious tackles. The speed of the tackler in matched non-injury tackles were distributed as follows – 42% ‘slow’, 32% ‘moderate’ and 26% ‘fast’ (n=19). The majority (80%, n=5) of ball-carriers were travelling ‘fast’ in injury situations, and in non-injury tackles 63% (n=19) were travelling ‘fast’ and 37% ‘moderately’. The ball-carrier's visual awareness was ‘apparent’ in 80% (n=5) of injurious tackles and 83% (n=19) of matched non-injury tackle events. However, in the one event where the injury was sustained by the ball-carrier, visual awareness was ‘absent’. In all the matched non-injury events for the ball-carrier (n=6), the ball-carrier's visual awareness was observed as ‘apparent’.
The direction of the tackle was ‘front’ in four of the five injurious tackles, with one being from the ‘side’. The body regions of the concussed tacklers who were struck were ‘head and neck’ in 75% and ‘shoulder/arm’ in 25% (n=4). In all matched non-injury tackle events, the body region of the tackler struck was ‘shoulder/arm’ (n=19). The head placement of the concussed tackler was observed as ‘in-front’ in three of the four concussive tackles, with the remaining one being ‘beside’. The concussed ball-carrier was contacted at the ‘shoulder/arm’. Ball-carrier fend was ‘absent’ in 80% of injurious tackles, whereas in non-injury tackles 47% of ball-carriers fended ‘moderately’, in 42% fending was ‘absent’ and in 11% ‘strong’(n=19).
Three of four concussed tacklers did not drive their legs after contact. The ‘legs’ were the most common body region to hit the ground first for the tackler in injury (80%) and non-injury (76%) tackle events (n=5 and n=17, respectively). The concussed ball-carrier's first body region on the ground was the ‘shoulder/arm’.
Ruck descriptors for injury and non-injury events
In three of the 