Thigh muscle injuries in youth soccer: predictors of recovery.

BACKGROUND: Participation in soccer at younger ages with attendant risk of muscle injury is increasing. PURPOSE: To delineate patterns of thigh muscle injury and predictors of recovery in male youth soccer academy players. STUDY DESIGN: Cohort study (prognosis); Level of evidence, 2. METHODS: Forty-one English Premiership soccer academy squads (all male, aged 8-16 years) over a 5-year period comprising 12 306 player seasons were studied prospectively for pattern, mechanism, and outcome after thigh muscle injury. Event analysis was used to identify independent predictors of slow recovery. RESULTS: A total of 1288 injuries were recorded representing an incidence (mean [SD]) of 0.42 (0.24) per thousand hours of training with a mean annual incidence of 0.52. Midfield players received the most injuries, followed by defense and attack positions. The quadriceps muscle group was most likely to be injured. There were 345 reinjuries (27%). Median time off for a primary injury was 13 days (interquartile range, 7-22 days) and 12 days (7-21 days) following a reinjury. Risk of such injury increased as the game progressed toward the end of the first half period (P = .028), and this risk persisted throughout the entire second half. There were 2 peaks of incidence (January and September). The percentage of the total for hamstring, adductor, and quadriceps injuries did not significantly change with player age. However, the proportion of injuries that were severe increased with age of player (t = 3.72, P = .010). Poor prognostic factors for recovery were hamstring injuries (z = 2.182, P = .029), contact injury (z = -3.137, P = .002), and older age (z = -2.2298, P = .022). CONCLUSION: The risk for prolonged recovery from thigh muscle injury was found to increase with age of the player and contact mechanism. The risk of injury increased toward the end of the first half, and this risk persisted throughout the second half. Delayed recovery was significantly associated with a hamstring muscle injury, first injury, and contact mechanism. This study, for the first time, allows identification of youth male soccer players at high-risk for prolonged symptoms after thigh muscle injury.