Active Voice: Can Tackle Technique Reduce Concussion Risk in Rugby Union?

By Gregory Tierney, MEng.

Viewpoints presented in SMB commentaries reflect opinions of the authors and do not necessarily reflect positions or policies of ACSM.

Gregory Tierney, MEng., is a student member of ACSM and a Ph.D. candidate in bioengineering at Trinity College, Dublin, Ireland. Gregory graduated top of his class in mechanical engineering from the University of Liverpool, England. The focus of his Ph.D. research is to biomechanically assess concussion and inertial head loading risk in rugby union. The goal is to identify suitable rule changes or injury prevention strategies to reduce this risk. The main approaches utilized in his thesis include video analysis, image processing, multibody modeling and 3D motion analysis. This commentary presents Mr. Tierney’s views on the topic related to a research article that he and three other colleagues authored. Their article appears in the March 2018 issue of
Medicine & Science in Sports & Exercise® (MSSE).

Rugby union is a territorial, dynamic and high-impact collision sport. Unfortunately, due to its physical and high-impact nature, the incidence of concussion is high. It is widely regarded that the tackle phase of play is the main cause of head impacts and, hence, leads to a relatively high prevalence of concussion in rugby union. However, the biomechanics and specific motion patterns associated with these head impacts are poorly understood. This is particularly concerning, given that players can make more than 30 tackles per game.

There is mounting evidence that current protective equipment and training to increase neck strength are insufficient to prevent concussion. This indicates the importance of head impact prevention strategies. It has been reported that the tackler is at highest risk of a head impact in rugby union. Therefore, the aim of this study, as our research group reported in the March 2018 issue of MSSE, was to identify tackle technique characteristics (developed by elite rugby union personnel) that have a positive influence on head impact prevention for the tackler.

The approach consisted of analyzing videos of tackle-related head impacts from a large sample of professional rugby union games over three seasons, thus allowing comparison of head impact cases (74) to non-injury cases (233). Although tackles can appear chaotic to spectators, player trends and patterns can be identified. Several easily coachable tackler technique characteristics were identified as having a lower propensity to result in a head impact. An example of these tackler technique characteristics includes “shortening steps” and “head up and forward/face up.” These examples are discussed below.

The “shortening steps” technique indicates that the tackler took shorter, faster steps when approaching the ball carrier. Tacklers exhibiting “shortening steps” ensured their feet remained active and afforded time to orientate themselves properly, as well as adapt to changes in the ball carrier’s motion/trajectory. It also has been reported that taking “shortening steps” reduces general injury risk for the tackler, as well as increases the tackler’s likelihood of dominating the tackle. Therefore, this characteristic carries the twin benefits of being both safe and effective. When the “shortening steps” technique was not exhibited, the tackler generally planted their feet during the pre-contact phase of the tackle and this was found to be associated with increased risk of a head impact. Notably, this finding is consistent with our previous work that identified foot planting as a risk factor for head impacts.

An ability to exhibit the characteristic “head up and forward/face up” resulted in the tackler being able to track the ball carrier’s motion and be aware of their surrounding environment. Thus, the tacklers susceptibility to receiving a head impact was reduced in this circumstance, particularly if the ball carrier exhibited an evasive maneuver. The findings of this study provide evidence for coaches to use in developing and implementing technical strategies that can reduce concussion among rugby players, potentially at all levels of competition. The approach undertaken in our study could also be utilized in other high-impact contact sports, such as American football, to identify similar trends.

There is mounting evidence of repeated head trauma being linked to brain degeneration in athletes. Player prevention strategies are an essential driving force in reducing concussion incidence.