ow’, 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 four injurious rucks (75%), the concussed player was acting defensively either in the capacity of ‘support’ (n=2) or as the ‘jackal’ (n=1; table 5). The role of non-injured players was distributed as follows: 43% were ‘support attack’, 39% ‘support defence’, 10% ‘jackal’ and 8% ‘ball-carrier’ (n=61). In three of the four concussive rucks (75%), the attacking team was ‘clearing the ruck’. In non-injury rucks, the attack was ‘clearing the ruck’ 52% of the time and ‘protecting the ball’ 48% (n=61) of the time. The defensive team were ‘competing for the ball’ in 75% of injurious rucks. Similarly, in non-injury rucks, the defensive team was ‘competing for the ball’ on the majority (70%, n=61) of occasions. The attack maintained possession in all concussive rucks and in 90% of non-injury rucks.
Aerial collision for injury and non-injury events
In the injurious aerial collision, both players involved were unaware of the impending contact (n=1; table 5). With regard to the speed of player(s), both players involved in injurious collision were moving at a pace classified as ‘fast’ (the injured player was the defensive player). In the matched non-injurious aerial collisions, all the defenders were moving at a pace classified as ‘moderate’ and the attackers were observed as ‘slow’ on all the occasions. Impact was ‘high’ in the injury event versus ‘low’ in all non-injury events. In the inciting event, the concussed player failed to land on (his) feet in a stable manner, whereas in all non-injury events this was maintained (n=3). The ‘attacker was higher than defender’ in the majority of injury (100%, n=1) and non-injury (67%, n=3) events. In the inciting event, the concussed player failed to land on (his) feet in a stable manner, whereas in all non-injury events this was maintained (n=3).
Insight into the injury mechanism of concussion in youth rugby
This is the first study to describe the global and local injury mechanisms of concussion and compares it with a representative and matched non-injury sample in youth rugby, which