Background The 9+ screening battery test consists of 11 tests to assess limitations in functional movement.
Aim To examine the association of the 9+ with lower extremity injuries and to identify a cut-off point to predict injury risk.
Methods Professional male football players in Qatar from 14 teams completed the 9+ at the beginning of the 2013/2014 and 2014/2015 seasons. Time-loss injuries and exposure in training and matches were registered prospectively by club medical staff during these seasons. Univariate and multivariate Cox regression analyses were used to calculate HR and 95% CI. Receiver operating characteristic (ROC) curves were calculated to determine sensitivity and specificity and identify the optimal cut-off point for risk assessment.
Results 362 players completed the 9+ and had injury and exposure registration. There were 526 injuries among 203 players (56.1%) during the two seasons; injuries to the thigh were the most frequent. There was no association between 9+ total score and the risk of lower extremity injuries (HR 1.02, 95% CI 0.99 to 1.05, p=0.13), even after adjusting for other risk factors in a multivariate analysis (HR 1.01, 95% CI 0.98 to 1.04, p=0.37). ROC curve analysis revealed an area under the curve of 0.48, and there was no cut-off point that distinguished injured from non-injured players.
Conclusion The 9+ was not associated with lower extremity injury, and it was no better than chance for distinguishing between injured and uninjured players. Therefore, the 9+ test cannot be recommended as an injury prediction tool in this population.
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Twitter Arnhild Bakken @phbakken
Contributors AB designed the study, contributed in data collection, analysed and interpreted the data, and drafted the article. RB designed the study, interpreted the data, revised the article and approved the final revision of the article. AF and RW contributed in data analysis, interpreted the data, revised the article and approved the final revision of the article. KMK, ST, TB, CE and JLT interpreted the data, revised the article and approved the final revision of the article.
Competing interests KMK is the Editor-in-Chief of BJSM and was at arm’s length (and blinded) from the review process.
Patient consent Obtained.
Ethics approval Institutional Review Board, Anti-Doping Lab Qatar (ADLQ), Doha, Qatar.
Provenance and peer review Not commissioned; externally peer reviewed.
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