Does the FIFA 11+ Injury Prevention Program Reduce the Incidence of ACL Injury in Male Soccer Players?
Silvers-Granelli HJ1,2, Bizzini M3, Arundale A4, Mandelbaum BR5, Snyder-Mackler L6.Clin Orthop Relat Res. 2017 Apr 7. doi: 10.1007/s11999-017-5342-5.
Overview of the study:
Population: Men who play competitive college soccer (NCAA DI/II)
Intervention: FIFA 11+ injury prevention program
Comparison: NCAA men’s soccer teams in DI and DII who did not undergo FIFA 11+ injury prevention program
Outcome: ACL injury
Study Design: prospective cluster randomized controlled trial
Time Frame: Fall 2012 season
Unit of clustering: Authors randomized the intervention by NCAA institutions’ team.
Hypothesized effect and level at which the exposure is measured (is it a characteristic of the cluster or the observation within the cluster): Authors hypothesized that the FIFA 11+ injury prevention program can reduce the overall number of ACL injuries in men who play competitive college soccer. Sixty-five institutions were randomized using a simple computer-generated randomization. Individual player informed consent, ACL injury, mechanism of injury, and date of return to play, age, position played, leg dominance were collected at the individual level.
Statistical model used to estimate the effect: Authors used frequency counts, t-tests, chi-square tests, factorial analysis of variance, and logistic regression tests.
Other statistical models that might be appropriate/preferable: We could conduct a multilevel model because data from the participants was collected a multiple levels, and a GEE would be preferable. However, I am not sure with my sample sizes (are they big enough?)—intervention group included 27 teams with 675 players, and control group included 34 teams with 850 players.