The First Decade of Web-Based Sports Injury Surveillance: Descriptive Epidemiology of Injuries in US High School Boys' Lacrosse (2008-2009 Through 2013-2014) and National Collegiate Athletic Association Men's Lacrosse (2004-2005 Through 2013-2014).

CONTEXT: The advent of Web-based sports injury surveillance via programs such as the High School Reporting Information Online system and the National Collegiate Athletic Association Injury Surveillance Program has aided the acquisition of boys' and men's lacrosse injury data.

OBJECTIVE: To describe the epidemiology of injuries sustained in high school boys' lacrosse in the 2008-2009 through 2013-2014 academic years and collegiate men's lacrosse in the 2004-2005 through 2013-2014 academic years using Web-based sports injury surveillance.

DESIGN: Descriptive epidemiology study.

SETTING: Online injury surveillance from lacrosse teams of high school boys (annual average = 55) and collegiate men (annual average = 14).

PATIENTS OR OTHER PARTICIPANTS: Boys' and men's lacrosse players who participated in practices and competitions during the 2008-2009 through 2013-2014 academic years in high school or the 2004-2005 through 2013-2014 academic years in college.

MAIN OUTCOME MEASURE(S): Athletic trainers collected time-loss (≥24 hours) injury and exposure data. Injury rates per 1000 athlete-exposures (AEs), injury rate ratios (IRRs) with 95% confidence intervals (CIs), and injury proportions by body site and diagnosis were calculated.

RESULTS: High School Reporting Information Online documented 1407 time-loss injuries during 662 960 AEs. The National Collegiate Athletic Association Injury Surveillance Program documented 1882 time-loss injuries during 390 029 AEs. The total injury rate from 2008-2009 through 2013-2014 was higher in college than in high school (3.77 versus 2.12/1000 AEs; IRR = 1.78; 95% CI = 1.63, 1.94). Most injuries occurred during competitions in high school (61.4%) and practices in college (61.4%). Injury rates were higher in competitions compared with practices in high school (IRR = 3.59; 95% CI = 3.23, 4.00) and college (IRR = 3.38; 95% CI = 3.08, 3.71). Lower limb injuries, muscle strains, and ligament sprains were common at both levels. Concussion was the most frequent competition diagnosis for all high school player positions.

CONCLUSIONS: Rates of time-loss injury were higher in college versus high school and in competitions versus practices. Attention to preventing common lower leg injuries and concussions, especially at the high school level, is essential to decrease their incidence and severity.