rature, highlighting the role of fatigue in concussion risk.25 ,26 A reduction in tackle technique proficiency has also been associated with fatigue in rugby league players, increasing the potential for unsafe tackles.27 In ice hockey, in-game fatigue was a significant predictor of concussion.26 This may warrant the need to coach contact technique during a state of fatigue for safe and effective execution during match play.27
Tackle contact techniques and concussion
The tackle situation contributed 50% of concussion injuries, which is higher than previously reported.28 ,29 The low sample size of this study, however, needs to be considered. The majority of injurious tackles were classified as ‘front-on’ with injury occurring to the tackler, a finding consistent with others who found that tackles from the front resulted in more injuries.8–10 While the nature of the game necessitates a high frequency of this type of tackle, the coaching of safe and effective techniques for all tackle types must be emphasised.
‘Head up and facing the ball-carrier before contact’, that is, ‘up and forward’, is specified in the list of instructions for safe and effective contact techniques.16 ,19 In this study, concussed players displayed a precontact position of head ‘up and forward’. However, on contact, the majority of players displayed a ‘down’ or ‘away’ head position. When a player tucks his chin on his chest into the ‘down’ position during a tackle, the risk for head or neck injury increases.10 This may be a target area for coaching interventions as players need to ensure that the ‘up and forward’ head position is maintained into contact and not only in preparation for contact.
Concussive impact may occur when a person's body and head are travelling at a particular speed and strike a solid object or when a head at rest is struck by a moving object.30 In 7 of the 10 concussive events, the injured player was either stationary or moving at a pace categorized as ‘slow’. In particular, most injured tacklers were categorised as either ‘stationary’ or ‘slow’, suggesting that difference in speed is a risk factor for concussion. Speed differences on contact during rugby have been noted before as a risk factor for injury in rugby.16 ,23 That said, the speed difference between players on contact, as a risk factor for injury, should not be interpreted in isolation.15 ,31
In the majority of injuries to the tackler, leg drive by the tackler was observed to be ‘absent’. BokSmart recommendations on safe tackling techniques emphasise the need for a player to maintain leg drive after contact.16 This particular technical point also increases the probability of tackle success.19
Ruck contact techniques and concussion
Rucks contributed the second largest proportion of concussions. In three of the four concussive rucks, the team on attack was ‘clearing the ruck’ while the defensive team was observed to be ‘competing for the ball’. These situations are characterised by players darting or charging into a mass of players, exposing players to potential risk of injury.32 Considering the observation that three of the four players injured in the ruck were acting in defence (2 as ‘support’ and 1 as ‘the jackal’), it seems that players fulfilling a defensive role in the ruck at the time the attack are clearing are more susceptible to concussive impacts. Additionally, all three of the players were unaware of the impending contact at the time of their injuries. It may therefore be useful to incorporate a coaching emphasis on ‘maintaining awareness’ for players engaging defensively during a ruck.
Strengths, limitations and implications
As mentioned earlier, the study is limited by its small sample size, and this ultimately restricted the statistical analyses. That said, the data are important as 3 years of concussion data in youth rugby are reported, and should be seen as setting the foundation for a longitudinal study with more injury and non-injury events. Future concussion research and application may benefit more from a refined video analysis coding system, similar t