Head Impact Exposure in Youth Soccer: Comparing across Activity Types

Abstract

Soccer is a popular youth sport in the United States, but the effect of repetitive head impacts experienced during training on neurocognitive outcomes is not well understood. Modifying practice structure may be an avenue for reducing head impact exposure and concussion risk in soccer, but research has yet to characterize head impact exposure across common soccer activities. The objective of this study was to compare head impact exposure across common training activities in soccer. Eight female soccer players practicing on an age 15 and under (U15) club team participated in this study for two soccer seasons. Players wore an instrumented mouthpiece sensor during all practice and game sessions. Research personnel recorded duration of all activities performed by each player to characterize player-specific exposure time. Film review was performed to identify head contact events during each session and classify events according to the activity and drill the player was performing. Head impact exposure for each athlete was quantified in terms of peak kinematics and impact rate. Mixed effects models were used to compare peak kinematics and generalized linear models were used to compare impact rates across drills and activity type. Drill and activity type were associated with peak kinematics and impact rate. Technical training activities accounted for the second-highest exposure time and were associated with higher impact rates and lower mean kinematics than other activity types. Team interaction activities and game play were associated with the highest rotational kinematics but the lowest impact rates. Head impact exposure in female youth soccer is influenced by the type of activity in which the athlete is engaged. Interventions designed to reduce head impact frequency in female youth soccer can benefit from targeting technical training activities; whereas, interventions designed to reduce head impact magnitude should target team interaction and game activities.