857 FO56 – Does a stakeholder informed law change reduce head contact and head acceleration events in men’s academy rugby league?

Background Head contact is a risk factor for concussion and given the potential long-term health risks from repeated head acceleration events (HAEs), law modification trials as preventative strategies are required. Objective Part 1. Establish important and feasible law modifications to reduce high magnitude HAE and head contact. Part 2. Examine effect of law modification in comparison to current laws in academy rugby league. Design Prospective cohort Setting Men's academy rugby league (RL) Participants Twelve academy RL teams, during 24 control and 24 law-modified matches. Interventions Part 1: Stakeholders (n=36 professional coaches, n=6 performance staff, n=2 medical staff, n=11 match officials, n=16 current or recently retired players) rated proposed law modifications based on importance (achieve desired outcome) and feasibility (maintains dynamics of RL; easy to implement). Part 2: Laws with the highest rating of importance (armpit tackle height) and feasibility (40m kick-off location) were implemented. Main Outcome Measurements Player actions via video analysis, HAEs via instrumented mouthguards (210 control vs. 152 law-modifications player-matches) and concussion rates. Focus groups to explore lived experiences of players, coaches and match officials. Results Contact to ball-carriers head/neck (control vs. law-modifications) was 43(95%CI; 39–48) vs. 31(27–34) per 1,000 tackles (p<0.001). Contact to ball-carries chest area was 310(298–322) vs. 377(364–390) per 1,000 tackles (p<0.001). With regards body position, both ball-carrier and tackler were upright 181(172–189) vs. 114(108–121) per 1,000 tackles (p<0.001). The number of HAEs >30g was 394(337–457) vs. 370(306–44) per 1,000-on-teeth-hours (p=0.06). The rate of concussion was 25.2 and 22.8 per 1000 match-hours. High-tackle penalties were awarded at a rate of 2.6(1.8–3.7) per 1,000 tackles vs. 74.8(69.6–80.2) per 1,000 tackles (p<0.001). Conclusions The law-modifications reduced contact to ball-carriers head, tackles where the ball-carrier and tackler were upright, although a large increase in high-tackle penalties were observed. The law modifications didn't significantly change HAE or concussion rates.