Evaluation of the Effectiveness of Anterior Cruciate Ligament Injury Prevention Programme Training Components: A Systematic Review and Meta-Analysis
Taylor JB, Waxman JP, Richter SJ, & Schultz SJ. British Journal of Sports Medicine. Epub ahead of print August 8, 2013; doi:10.1136/bjsports-2013-092358
Take Home Message: ACL prevention programs, that are effective at reducing ACL injuries when focusing on stretching, strength, and agility activities, can be done in relatively short warm up periods with little to no disruption to practice activities.
Anterior cruciate ligament (ACL) injury prevention programs have been developed in efforts to decrease the likelihood that an athlete suffers an injury, especially females. There are a wide array of programs available, which has lead to confusion and mixed results. The purpose of this meta-analysis was to investigate ACL prevention program and objectively quantify the duration, points of emphasis, and effectiveness in female athletes. A literature search yielded 13 studies that met the inclusion criteria: 1) randomized controlled trial or prospective cohort study, 2) ACL incidence reported or calculated, 3) included specific exercise descriptions, and 4) training session durations were reported. Overall, the intervention programs reduced the rate of ACL injury. The duration of a single training session ranged from 10 to 44 minutes and the programs included 10 to 108 sessions. However, the authors found that the total training time (number or duration of training sessions) did not influence ACL injury rates. The exercises within each program were further categorized into 5 areas: strength, explosive, balance, agility, or stretching. Most programs (69%) included strength, explosiveness, and agility exercises, while less programs included balance exercises (54%) or stretching exercises (23%). The majority of the programs emphasized balance and agility exercises. Overall, ACL injury risk increased as the duration of balance exercises increased, but non-contact ACL injuries decreased as the duration of stretching exercises increased. A subgroup analysis revealed no differences between athletes that did or did not receive feedback during the exercise program.
Clinically, this meta-analysis reveals that ACL prevention programs reduce the risk of ACL injury in females, and having an intervention program is more important than duration, number of sessions, or feedback. Therefore, we can offer a short and efficient program to busy coaches and teams that may reduce the risk of ACL injury. During this potentially short and efficient program, we may minimize the time dedicated to balance training and instead focus on stretching, strengthening, and agility activities. While strength and agility exercises did not significantly influence the rate of ACL injuries, there was a trend suggesting they may be important. More research needs to be done on these activities to determine whether ACL prevention programs improve strength and/or induce neural adaptations. Regardless, this meta-analysis demonstrates that these programs may be short, focused on stretching as well potentially strength/agility activities, and introduced to a team to do on their own as part of their warm up. Coaches may be able deploy these programs to reduce the risk of ACL injury and not take away precious time from practice.
Questions for Discussion: Do you think that we have enough information to potentially develop more efficient and effective ACL prevention programs? Do you favor emphasis on a particular component of training or giving feedback during programs?
Written by: Nicole Cattano
Reviewed by: Jeffrey Driban