A sport fitness index for assessment of sport-related injury risk

Objective: To develop and validate a concise survey that will identify athletes who possess elevated injury risk. Design: Cohort study. Setting: National Collegiate Athletic Association Division I athletic program. Participants: Cohorts of 188 and 146 college athletes who participated during successive academic years. Assessment of Risk Factors: The first cohort provided responses to 4 joint-specific outcome surveys that were related to subsequent time-loss injury occurrence. Receiver operating characteristic analysis identified survey items that provided best discrimination, which were combined with a negative life event stress item to create a new 10-item survey. The second cohort provided responses to the new survey, which were converted to a 0 to 100 score. Main Outcome Measures: Construct validity was assessed through documentation of time-loss injuries sustained during the preceding 12 months and predictive validity was assessed through prospective documentation of sport-related sprains and strains. Cronbach alpha was calculated to assess internal consistency. Results: Each of the outcome survey items used to develop the new survey demonstrated much greater specificity than sensitivity. Both the retrospective and prospective receiver operating characteristic (ROC) analyses identified scores of 96 and 88 as cut-points that provided good discrimination between injured and noninjured cases. The area under the curve was 0.69 (P < 0.001) for the retrospective analysis and 0.62 (P 0.016) for the prospective analysis. Cronbach alpha was 0.89 (90% CI, 0.86-0.91). Conclusions: Self-reported effects of previous injury may be one method to efficiently identify athletes who possess elevated injury risk, and subsequently deliver preventive interventions, thereby providing an alternative method to time-intensive functional testing.