Tackling sport-related concussion: effectiveness of lowering the maximum legal height of the tackle in amateur male rugby - a cross-sectional analytical study.

OBJECTIVE: Rugby union ('rugby') is popular globally, with most of its participants being amateur. Concern regarding sport-related concussion (SRC) sustained during rugby is increasing. SRC occurs most frequently in the tackle, yet few interventions have aimed to mitigate this risk factor. This study investigated the influence of a lowered legal tackle height on SRC incidence in amateur rugby. DESIGN: Cross-sectional analytical study: 2018 (control-standard tackle height) and 2019 (intervention-lowered legal tackle height) seasons. SETTING: South African collegiate student rugby competition. PARTICIPANTS: Between 800 and 900 male amateur student players (age: 20±1.6 years) in each year. INTERVENTION: Maximum legal tackle height lowered from line of the shoulder on the ball carrier to the line of the armpit. OUTCOME MEASURES: Number of overall (medical attention) and time-loss (≥1 day lost) injuries, head injuries and SRCs in 2018 and 2019 (dependent variables); events associated with injury incidents (independent variables). RESULTS: There was no statistically significant difference in incidences of time-loss injuries (IRR: 0.79; 95% CI: 0.6 to 1.1; p=0.13), head injuries (IRR: 0.83; 95% CI: 0.5 to 1.3; p=0.42) and SRC (IRR: 0.69; 95% CI: 0.4 to 1.2; p=0.20). In 2018 and 2019, most time-loss head injuries (57%, n=43) and SRCs (55%, n=26) occurred during the tackle. CONCLUSIONS: Despite a trend towards reducing injuries, head injuries and SRC, lowering maximum legal tackle height to armpit level did not change SRC incidence in this amateur male rugby cohort. Most time-loss head injuries and SRCs occurred during the tackle. Further tackle-related interventions to reduce SRC incidence require investigation.

Tackling the tackle 2: Evaluation of referee and player behavioural change as measures of implementation of a law variation in community-level male amateur rugby union.

OBJECTIVES: To evaluate player and referee behaviour during a lower tackle height law variation trial in community rugby union ('rugby'). DESIGN: Prospective observational cohort study. METHODS: In a law variation trial in male amateur community rugby, coded match video surveillance data were analysed. Referee (sanctioning rate) and player (tackler body position) behaviour changes over one season (under the lowered, armpit-level maximum legal tackle height condition) were analysed in three approximately equal periods of the season. Secondarily, an independent professional referee reviewed illegal high tackle sanctioning data. RESULTS: Overall, 108 matches with 14,780 tackles were filmed and coded. Sanctioned illegal high tackle propensity was significantly higher in the mid-season (41 sanctioned high tackles/1000 tackle events; 95 % CI: 35-47), compared with first and last periods. Upright tacklers in tackles decreased significantly in the final vs. middle period of the season (rate ratio: 0.69; 95 % CI: 0.54-0.88; p < 0.01). Of all the coder-determined high tackles also assessed as high under the new law by the independent referee, 51 % were sanctioned by the on-field referee. CONCLUSIONS: Positive player and referee behavioural changes were observed during a lowered legal tackle height law variation in this community rugby setting. Increased mid-phase high tackle sanctioning by referees was followed by fewer tackles with upright tacklers in the subsequent (last) phase of the season. Encouraging positive behaviour changes of this nature, particularly if sustained (beyond trial study periods), may contribute to overall injury risk reduction, and hold considerable importance to inform future injury prevention strategies in rugby.

Tackling the tackle 1: A descriptive analysis of 14,679 tackles and risk factors for high tackles in a community-level male amateur rugby union competition during a lowered tackle height law variation trial.

OBJECTIVES: In rugby union (rugby), the tackle is the most frequent cause of concussion and thus a target for intervention to reduce concussion incidence. The aim of this study is to describe tackle characteristics and factors associated with illegal high tackles in amateur community-level rugby during a lowered (armpit level) tackle height law variation trial. DESIGN: Prospective observational cohort study. METHODS: Video surveillance of a single season, four-league competition with coding of video data according to a predefined coding framework. Descriptive statistics of tackle detail and logistic regression was performed to analyse factors associated with high tackles. RESULTS: One hundred and eight matches with 14,679 tackles and a mean of 137 (±30) tackles per match were analysed. High tackles (above armpit level) had significantly greater odds of occurring in the lower (2nd-4th) leagues (OR: 1.95; 95 % CI: 1.6-2.4; p < 0.001), front-on tackles (OR: 1.61; 95 % CI: 1.3-2.0; p < 0.001), arm tackles (OR: 1.65; 95 % CI: 1.3-2.1; p < 0.001), bent-at-waist ball carrier (OR: 1.93; 95 % CI: 1.6-2.4; p < 0.001), falling/diving ball carrier (OR: 2.21; 95 % CI: 1.6-3.1; p < 0.001), and an upright tackler (OR: 3.38; 95 % CI: 2.7-4.2; p < 0.001). A falling/diving tackler had significantly lower odds of being associated with a high tackle (OR: 0.44; 95 % CI: 0.3-0.6; p < 0.001). CONCLUSIONS: Overall mean tackles per match were similar to those of senior amateur and elite rugby. League, tackle type, tackle aspect, and player body positions were associated with high tackles. These findings reiterate the need for ongoing efforts to identify and implement mitigating strategies to reduce tackle-related injury risk.