Time Trends in Incidence and Severity of Injury among NCAA Soccer Players, 1990–1996 and 2004–2009

Abstract

People under age 25 years comprise the largest cohort of soccer players in the U.S.; yet, the descriptive epidemiology of injury in this age group is limited. Moreover, there have been few analyses of injury occurrence across time that would allow investigators to monitor trends in response to changing practices and policies. PURPOSE: To identify trends in injury incidence and severity between two time periods (1990-1996 and 2004-2009) in NCAA soccer players. METHODS: Data were analyzed from the National Collegiate Athletic Association Injury Surveillance System (NCAA-ISS). As per data collection guidelines, injury incidence was defined as: 1) any injury event that occurred during participation in an intercollegiate game or practice; 2) that required medical attention; and 3) restricted participation or performance for >1 day beyond the event. To account for varying levels of playing exposure among the athletes we calculated Athlete-Exposure (AE), defined as a single athlete participating in a single practice or competition with any probability of injury. Incidence density then was calculated as the number of events per 1000 AE within each time period. The rate ratio (RR), along with the 95% confidence interval (CI), compared incidence density and severity in 2004-2009 relative to 1990-1996. RESULTS: Overall injury rates were significantly lower in the 2004-2009 cohort compared with the 1990-1996 cohort [RR=0.88 (95%CI=0.86, 0.91)] and this was true for almost every category of injury studied. The lower rates were especially noticeable for recurrent injuries [RR=0.62 (95%CI=0.57, 0.68)], short-term injuries [RR=0.69 (95%CI=0.67, 0.72)] and for injuries requiring surgery [RR=0.35 (95%CI=0.29, 0.41)]. There was also a significant reduction in injuries occurring during games, particularly during the second half [RR=0.69 (95%CI: 0.66, 0.73)]. In contrast, we observed a significant increase in rates of long-term (>7 days of lost time) injuries between the two time periods [RR=1.33 (95%CI=1.27, 1.40)]. CONCLUSIONS: Given the prominence of soccer play in the United States, public health efforts should promote the use of this surveillance system to better inform and evaluate injury prevention practices and policies directed toward player safety.