Background Injury knowledge and beliefs influence uptake of injury prevention programs. The effect of exposure to prevention programs on knowledge and beliefs is not well understood.

Objective To explore the effect of exposure to the FIFA 11+ program on the injury knowledge and beliefs of female youth soccer coaches and players.

Design A sub-cohort analysis from a cluster-randomized controlled trial.

Setting Youth soccer league venues in Alberta, Canada.

Participants 31 female teams [coaches n=29, players (ages 13–18) n=258].

Risk factor assessment Teams recorded FIFA 11+ adherence during the season.

Main outcome measurements Coaches and players completed pre-season and post-season questionnaires to assess changes in injury knowledge and prevention beliefs after FIFA 11+ exposure.

Results At baseline, 62.8% (95% CI: 48.4–77.3) of coaches and 75.8% (95% CI: 71.5–80.1) of players considered "inadequate warm-up" a risk factor for injury. There was no effect of 11+ adherence on this belief (odds ratio=1.0; 95% CI: 0.9–1.1), although more players (78.7%; 95% CI: 73.77–83.7) than coaches (51.7%; 95% CI: 33.55–69.9) considered "inadequate warm-up" a risk factor at post-season. At baseline, 13.8% (95% CI: 1.3–26.4) of coaches believed a warm-up could prevent muscle injuries, but none believed it could prevent knee and ankle injuries. For players, 9.7% (95% CI: 6.1–13.3), 4.7% (95% CI: 2.1–7.3), and 4.7% (95% CI: 2.1–7.3) believed a warm-up would prevent muscle, knee, and ankle injuies, respectively. There was no effect of adherence on post-season beliefs that a warm-up could prevent an injury, for coaches or players.

Conclusions Exposure to the FIFA 11+ appears insufficient for changing injury risk or prevention beliefs over a single season. This could have implications for program delivery strategies and may influence sustained program use.