Characteristics of head impacts sustained by intercollegiate soccer athletes during free play and set pieces

Context: Determining which scenarios in soccer involve higher occurrence of head impacts may allow initiatives to improve technique to limit the risk of injury. Objective: To compare the frequency and magnitude of head impacts sustained by intercollegiate Division III soccer players based on free-play or set-pieces during games. Design: Descriptive epidemiology study. Setting: Soccer fields. Participants: 21 National Collegiate Athletic Association Division III soccer players. Intervention: The independent variable of this study was game scenarios (continuous free-play and set-pieces). Main Outcome Measures: X2 Biosystems (Seattle, WA) xPatch sensors collected linear acceleration (g), rotational acceleration (deg/sec2) and frequency of head impacts over 10 g confirmed by video analysis. Results: Participants were more likely to sustain a head impact during free-play (IR=653.92, CI95=582.83-725.02) compared to set pieces (IR=346.08, CI95=294.36-397.80; IRR=1.89, CI95=1.57-2.27). Game scenario did not significantly alter linear accelerations (F2,1=1,P=.35, η2=.002,1-β=.16) or rotational accelerations (F2,1=1.82,P=.18, η2=.004,1-β=.27). Conclusion: The higher number of impacts during free-play could be from the larger opportunity for impact. Education of spacial awareness during this gameplay could be beneficial to improve reaction and anticipation of impacts.The flow of the game should be monitored because of no whistle precursor to dangerous situations. Keywords: frequency, concussion, X2