FAIR PLAY AS AN INJURY PREVENTION INTERVENTION: DO YELLOW CARD ACCUMULATION POLICIES REDUCE HIGH SCHOOL SOCCER INJURIES?

Background: Pediatric sports-related injuries are common, yet prevention efforts too often go unevaluated. Collins et al. studied nine U.S. high school (HS) sports during 2005/06-2006/07, finding boys’ and girls’ soccer had the highest injury rates related to illegal activity. Several states have implemented yellow card accumulation policies (YCPs) in an effort to prevent injuries. Hypothesis/Purpose: Purpose: Evaluate the effectiveness of YCPs in reducing HS soccer competition injuries by comparing injury rates and patterns in states with and without YCPs. Hypotheses: Athlete-athlete contact injury rates are lower in states with YCPs Severe injuries (concussion, fracture, ACL, injury requiring surgery, injury resulting in > 3 weeks’ time loss) are less prevalent in states with YCPs Gender differences influence the effectiveness of YCPs Methods: Retrospective cohort study of NHFS member state association HS soccer players injured during competition in 2005/06-2017/18. Athlete exposure (AEs) and injury data collected from a national sports injury surveillance system, High School RIO. Poisson regression assessed the effects of YCPs on injury rates and patterns. Results: Of 50 NFHS member states associations, high schools from 47 were represented. Overall, 901 athlete-athlete contact injuries occurred during 352,775 competition AEs in states with YCPs and 3,525 during 1,459,708 AEs in states without YCPs. There was no significant difference in overall contact injury rates (rate ratio [RR] 1.06; 95% confidence interval [CI]: 0.98-1.14) between schools in states with and without YCPs. A small, significant increase in overall contact injury rates was discernable after states’ adoption of YCPs (RR 1.17; 95% CI: 1.03, 1.34), particularly in boys’ soccer (RR 1.32; 95% CI 1.08-1.62). A significantly lower proportion of injuries resulting in > 3 weeks’ time loss occurred in states with YCPs (injury proportion ratio [IPR] 0.81; p=0.047), while other severe injuries did not differ. There were no significant differences in YCPs’ effect by gender (p=0.319). Conclusion: Among HS boys’ and girls’ soccer players, playing in states with YCPs did not lower athlete-athlete contact injury rates, although injuries resulting in > 3 weeks’ time loss were less prevalent in states with YCPs. Athlete-athlete contact injury rates were slightly higher in states following adoption of YCPs, particularly in boys’ soccer. Enactment of YCPs alone, without proper enforcement, may not be a sufficient injury prevention strategy. Further studies assessing the impact of HS soccer YCPs need to consider the effects of state level YCP enforcement, documented illegal activity/foul play, and Fair Play education. Tables/Figures: Table 1. Rate of Athlete-Athlete Contact Injuries Sustained During Soccer Competition in High Schools in States with and without Yellow Card Policies, National High School Sports-Related Injury Surveillance Study, USA, 2005/06-2017/18 # Injuries # Competition AEs Rate per 10,000 AE RR (95% CI) a Overall With YCP 901 352775 25.5 1.06 (0.98, 1.14) Without YCP 3525 1459708 24.1 Ref Boys’ Soccer With YCP 430 188626 22.8 1.10 (0.99, 1.22) Without YCP 1625 783851 20.7 Ref Girls’ Soccer With YCP 471 164149 28.7 1.02 (0.92, 1.13) Without YCP 1900 675857 28.1 Ref aRate Ratio (RR) is the ratio of total injury rate in YCP schools to total injury rate in No YCP schools. Table 2. Rate of Athlete-Athlete Contact Injuries Sustained During Soccer Competition in High Schools in states with Yellow Card Policies Pre- and Post- Policy Enactment, National High School Sports-Related Injury Surveillance Study, USA, 2005/06-2017/18 # Injuries # Competition AEs Rate per 10,000 AE RR (95% CI) a Overall Post-YCP 901 352775 25.5 1.17 (1.03, 1.34) Pre-YCP 285 130686 21.8 Ref Boys’ Soccer Post-YCP 430 188626 22.8 1.32 (1.08, 1.62) Pre-YCP 118 68262 17.3 Ref Girls’ Soccer Post-YCP 471 164149 28.7 1.07 (0.90, 1.28) Pre-YCP 167 62424 26.8 Ref aRate Ratio (RR) is the ratio of total injury rate in Post YCP enactment to total injury rate in Pre YCP enactment. Table 3. Severe Athlete-Athlete Contact Injuries Sustained During Soccer Competition in High Schools in states with and without Yellow Card Policies, National High School Sports-Related Injury Surveillance Study, USA, 2005/06-2017/18 Injury YCP# (%)b No YCP# (%) IPR (95% CI)a Concussion 247 (27.4) 945 (26.8) 1.03 (0.88,1.22) Fracture 72 (8.0) 321 (9.1) 0.87 (0.66,1.13) ACL 34 (3.8) 120 (3.4) 1.11 (0.76,1.64) Injury required surgical intervention 51 (5.7) 199 (5.7) 1.00 (0.73,1.38) Injury resulting in >3 weeks’ time lossc 124 (13.8) 581 (16.5) 0.81 (0.66, 1.00)d aInjury Proportion Ratios (IPRs). For all IPRs, No YCP is the referent category. bFor each category of injury above, % indicates what proportion of all athlete-athlete contact injuries sustained during soccer competition were accounted for by the specific injury category. cInjury resulting in >3 weeks’ time loss includes the following categories: “Returned to activity in 22 days or more,” “medical disqualification for season,” or “medical disqualification for career. ” dAn upper limit of 95% CI equals 0.997, which is less than 1.00.