Sport Specialization , Injury and Illness: A Prospective Study of Elite Female Adolescent Soccer Players

ContextAlthough considerable cross-sectional evidence exists regarding the association between sport specialization and injury, sport-specific, prospective research is lacking. Similarly, sport specialization is associated with impairments in sleep and subjective well-being in youth athletes, but it is unknown whether this increases the risk of illness. ObjectiveTo determine the relationship between sport specialization status and in-season injury and illness risk in elite female adolescent soccer players. DesignProspective Cohort Study SettingPre-season evaluation of maximal aerobic capacity (VO2max) and sport specialization, and in-season self-reporting of daily training load (session-rating of perceived exertion), injury and illness resulting in lost sport participation time. Participants80 female youth soccer players (ages 13-18) from a local youth soccer organization. Main outcome measuresSport specialization status, injury and illness incidence during two 4-month competitive soccer seasons. Athletes were considered specialized if they participated in soccer exclusively versus multiple sports during the year. Mixed effects logistic regression models were used to individual injury and illness (yes/no) during the study period, using sport specialization, age, and training load as fixed effects and individual athlete as a random effect. ResultsSpecialized (n=46) athletes did not differ from non-specialized (n=34) athletes with respect to age, preseason physical activity, VO2max or in-season training load (all p>0.05). No difference was seen in the proportion of individuals from each group that reported an in-season injury (specialized = 19% v 17%, p=0.83) or illness (40% v 38%, p=0.82). After adjusting for age and training load, the individual injuries (OR= 0.86 [0.26, 2.8], p=0.81) and illnesses were not significantly predicted by specialization (OR= 1.06 [0.45, 2.5], p=0.89). ConclusionsAfter adjusting for age and training load, sport specialization status was not associated with in-season injury or illness risk in elite female soccer players. Key pointsO_LIPrior research regarding the associations between sport specialization and health outcomes has been primarily cross-sectional and failed to account for the confounding role of training load. C_LIO_LIAmong elite adolescent female soccer players with similar pre-season physical activity levels in-season training loads, sport specialization was not associated with injury or illness incidence across two competitive seasons. C_LI