Football (soccer) is a popular sport world-wide. Despite the health benefits of playing football, non-contact musculoskeletal injuries (eg, hamstring strain) are relatively common. Exercise-based programs have been developed to prevent injury, but previous evaluations have not differentiated between contact and non-contact injuries. This systematic review aimed to estimate the effects of exercise-based programs compared to control to prevent non-contact musculoskeletal injuries in football players.
Guided by a prospectively registered protocol, sensitive searches of six databases (including Medline, Embase and PEDro), three clinical trial registries and citation tracking were performed to identify randomised controlled trials evaluating exercise-based injury prevention programs. The participants were football players aged 13 years and older. The intervention was any exercise therapy performed to develop function, skills or physical fitness. The comparator could be usual training or warmup, minimal intervention, education or no intervention. The primary outcome was the occurrence of any acute sudden onset musculoskeletal injury that occurred without physical contact with another player or object on the field. In addition to reporting the number of non-contact injuries, included trials needed to report the number of exposure hours for each group. Two reviewers independently selected trials and extracted data. Disagreements were resolved through discussion or arbitration by a third reviewer. Risk of bias was evaluated using the PEDro scale, with scores downloaded from the PEDro database and confirmed by one reviewer. Certainty of evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. The number of non-contact injuries and exposure hours were used to calculate the injury incidence rate per 1,000 hours and the injury risk ratio. Meta-analysis was used to compute the pooled injury risk ratio and its 95% confidence interval (CI). One pre-planned subgroup analysis was undertaken based on exercise type: focused/unimodal (exercises chosen to train and protect a specific muscle or joint) vs. generalised/multimodal (exercises that targeted many body segments) on non-contact hamstring injuries.
10 trials (13,355 participants) were included in the meta-analyses. The trials were conducted in the United States, Norway, and the Netherlands (2 trials each) and in Germany, Japan, Nigeria and Sweden (1 trial each). Only male players were included in 6 trials and only female players in 4. Most trials (7) recruited youth players and all trials included amateur players. The duration of the exercise-based program ranged from 3 to 9 months. Focused exercise was used in 3 trials (Nordic Hamstring Exercise, Bounding Exercise Program) and generalised exercise in 7 (Prevent Injury and Enhance Performance Program, FIFA 11+, FIFA 11, Knäkontroll (neuromuscular training)). All interventions were applied at least twice a week to every training session.
Exercise-based programs reduce the risk of non-contact injuries by 23% compared to control, with an injury risk ratio of 0.77 (95% CI 0.61 to 0.97; 10 trials; 13,355 participants; low certainty). The sub-group analysis revealed that focused programs were not different from generalised programs for the prevention of non-contact hamstring injuries. The injury risk ratio was 0.65 (0.44 to 0.97; 3 trials; 1,238 participants; low certainty) for focused programs and 0.63 (0.19 to 2.12; 3 trials; 2,573 participants; very low certainty) for generalised programs.
Exercise-based prevention programs may reduce the risk of non-contact musculoskeletal injuries in football players. Hamstring-focused programs did not reduce hamstring injury any more than general programs.
Lemes IR, et al. Do exercise-based prevention programmes reduce non-contact musculoskeletal injuries in football (soccer)? A systematic review and meta-analysis with 13,355 athletes and more than 1 million exposure hours. Br J Sports Med 2021 May 17:Epub ahead of print
