Background Participants' compliance, attitudes and beliefs have the potential to infl uence the effi cacy of an intervention greatly. Objective To characterise team and player compliance with a comprehensive injury prevention warm-up programme for football (The 11+), and to assess attitudes towards injury prevention among coaches and their association with compliance and injury risk. Study Design A prospective cohort study and retrospective survey based on a cluster-randomised controlled trial with teams as the unit of randomisation. Methods Compliance, exposure and injuries were registered prospectively in 65 of 125 football teams (1055 of 1892 female Norwegian players aged 13-17 years and 65 of 125 coaches) throughout one football season (March-October 2007). Standardised telephone interviews were conducted to assess coaches' attitudes towards injury prevention. Results Teams completed the injury prevention programme in 77% (mean 1.3 sessions per week) of all training and match sessions, and players in 79% (mean 0.8 sessions per week) of the sessions they attended. Compared with players with intermediate compliance, players with high compliance with the programme had a 35% lower risk of all injuries (RR 0.65, 95% CI 0.46 to 0.91, p=0.011). Coaches who had previously utilised injury prevention training coached teams with a 46% lower risk of injury (OR 0.54, 95% CI 0.33 to 0.87, p=0.011). Conclusions Compliance with the injury prevention programme was high, and players with high compliance had signifi cantly lower injury risk than players with intermediate compliance. Positive attitudes towards injury prevention correlated with high compliance and lower injury risk.

Dette er siste tekst-versjon av artikkelen, og den kan inneholde små forskjeller fra forlagets pdf-versjon. Forlagets pdf-versjon finner du på www.sage.com: http://dx.doi.org/10.1177/0363546515625048 This is the final text version of the article, and it may contain minor differences from the journal's pdf version. Background: The evidence linking knee kinematics and kinetics during a vertical drop jump (VDJ) to anterior cruciate ligament (ACL) injury risk is restricted to a single small sample. Still, the VDJ test continues to be advocated for clinical screening purposes.

Background: The incidence of lower extremity injuries in female soccer players is high, but the risk factors for injury are unknown. Purpose: To investigate risk factors for lower extremity injuries in elite female soccer players. Study design: Cohort study. Methods: Players in the Norwegian elite female soccer league (N=12 teams) participated in baseline screening tests prior to the 2009 competitive soccer season. The screening included tests assessing maximal lower extremity strength, dynamic balance, knee valgus angles in a drop jump landing, knee joint laxity, generalized joint laxity and foot pronation. We also included a questionnaire to collect information on demographic data, elite level experience and injury history. Time-loss injuries and exposure in training and match were recorded prospectively in the subsequent soccer season using weekly text messaging. Players reporting an injury were contacted to collect data regarding injury circumstances. Univariate and multivariate regression analyses were used to calculate odds ratios (OR) and 95% confidence intervals (CI) for one standard deviation change. Results: In total, 173 players provided complete screening tests and registrations of injuries and exposure throughout the season. A total of 171 injuries in 107 players (62%) were recorded, and ligament and muscle injuries were most frequent. Multivariate analyses showed that greater BMI (OR 1.51, CI 1.00-1.90, p≤0.001) was the only factor significantly associated with new lower extremity injuries. Greater BMI was associated with new thigh injuries (OR 1.51, CI 1.08-2.11, p=0.01), lower knee valgus angles in a drop jump landing was associated with new ankle injuries (OR 0.64, CI 0.41-1.00, p=0.04) and a previous knee injury with new lower leg and foot injuries (OR 3.57, p=0.02), whereas neither of the factors investigated influenced the risk of new knee injuries. Conclusion: Greater BMI was found to be a risk factor for lower extremity injuries in elite female soccer players. Clinical relevance: Increased knowledge on risk factors for lower extremity injuries enables more targeted prevention strategies with the aim of reducing injury rates in female soccer players. Keywords: female; football; soccer; injury; risk; screening What is known about the subject: The incidence of lower extremity injuries in female soccer players is high, but the knowledge regarding risk factors for injury is limited.