Sports Medicine Research: In the Lab & In the Field: New Evidence Supporting ACL Injury Prevention Warm-up Programs (Sports Med Res)
Friday, September 7, 2012

New Evidence Supporting ACL Injury Prevention Warm-up Programs

Prevention of acute knee injuries in adolescent female football players: cluster randomized controlled trial.

Waldén M, Atroshi I, Magnusson H, Wagner P, Hägglund M. BMJ. 2012 May 3;344:e3042. doi: 10.1136/bmj.e3042.
http://www.ncbi.nlm.nih.gov/pubmed/22556050 (full text available for free)

Soccer is a popular sport throughout the world; however, female soccer athletes are much more prone to anterior cruciate ligament (ACL) injury than their male counterparts.  One theory why female athletes are more prone to ACL injuries involves the different firing patterns of the muscles in the lower extremity in women compared to men, which leads to increased valgus load at the knee in females.  Considering this hypothesis, is there a short, effective, and applicable intervention that could be implemented on a large scale to help prevent ACL injuries?  The aim of this randomized clinical trial was to evaluate the effectiveness of a neuromuscular warm-up program to reduce acute knee injuries, and more specifically ACL injuries, among adolescent female soccer players.  In this study, 4564 female soccer players between the ages of 12 and 17 years (in 309 soccer clubs) were randomly divided based on their teams into two parallel study groups: control group (2085 athletes in 155 clubs) and intervention (2479 athletes in 154 clubs).  A neuromuscular warm-up program was designed focusing on knee control and core stability and was comprised of 6 exercises, further subdivided into four steps with progressive difficulty.  The program took about 15 minutes to complete and was implemented in the intervention group and maintained through the entire duration of the soccer season.  The study staff taught the program to the coach and one player on each team.  Compliance was monitored by coaches during each training session in addition to random spot checks by physiotherapists throughout the study duration.  Coaches also notified the physiotherapists of any knee injuries and the clinician then conducted an evaluation.  Severe knee injuries were defined as an absence from play for more than four weeks.  The authors noted that the intervention group had less ACL injuries (7 injuries, 0.28%) than the control group (14 injuries, 0.67%); a 64% reduction.  However, there were no differences between the groups in regards to the additional end points of severe knee injuries or any acute knee injury.  The authors provided some evidence that severe knee injuries or any acute knee injuries may have been lower among those considered compliant with the intervention program compared to the control group.

The findings of the study suggest that a structured 15-minute neuromuscular warm-up program can help reduce the number of ACL injuries in adolescent female soccer players.  One advantage of such warm-up program is that it is monitored and implemented by the coaching staff and only requires minimal outside intervention.  Therefore, it can serve as a preventive tool for ACL injuries in female adolescent players.  The impact on ACL injury prevention by a neuromuscular warm-up program was also echoed in a previous study by Mandelbaum et al.  It demonstrated that a neuromuscular and proprioception training program may help reduce the occurrence of ACL injuries over the long-term.  In summary, more research is needed to establish the validity and clinical benefit of neuromuscular warm-up programs to prevent ACL injuries specifically and all knee injuries in general.  The biggest limitation of this study is that it was neither designed nor powered to look at the rate of injury reduction during contact vs. non-contact ACL injuries with and without a neuromuscular warm up.  Do you incorporate a neuromuscular training program with your adolescent females?  Do you think these findings may be applied to other female sports as well as male sports?

Written by: Christian Glaser, DO and Marc I. Harwood, MD reviewed
Reviewed by: Jeffrey Driban

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Waldén M, Atroshi I, Magnusson H, Wagner P, & Hägglund M (2012). Prevention of acute knee injuries in adolescent female football players: cluster randomised controlled trial. BMJ (Clinical research ed.), 344 PMID: 22556050

6 comments:

Bethany said...

I have worked with both high school and division 1 female soccer teams in the last two years and only had 1 ACL injury. Although I am just starting out in my career, I have been doing a lot of reading about ACL injury prevention programs. Neither school I worked at had any kind of program for the athletes, but that is something that I would like to definitely try to include if I am working with a women's soccer team or other high-risk sport (like women's gymnastics or w. basketball). Many of the prevention programs out there incorporate multiple different types of training (balance, plyometric, landing, etc) and have varying lengths (anywhere from 15 to 90 minutes). I think that this study is good, but that it would be helpful to know which types of training are most effective and how much time should be devoted to the training. Also, some other types of training preograms warrant consideration. Dance training, for instance, would probably have good results as a prevention program.

Christian Glaser said...

Thank you for your comment. You raise an important point about ALC injuries, the choice and duration of prevention program. Currently Tim Hewitt and Mandelbaum are focusing parts of their research on that topic and both agree on the benefit of a warm up program. As you pointed out, there are many different programs available but a couple of important factors need to be considered when choosing a warm up program: length and complexity. Most of the programs are implemented and supervised by the coaching staff, which potentially could serve as the limiting factor in their use.
There is most certainly the need for more research in this field to address the above asked questions but also to evaluate the long term benefit of warm up programs in ACL injury prevention.

Kaitlyn Johnson said...

I think that adding in a neuromuscular training program can be very beneficial. So many adolescent females are getting knee injuries and ACL injuries. Adding in a program, which can help limit the number of ACL injuries, will be a good thing and could also help further down the road when these athletes continue on to college. I think that these findings could be added in with basketball players. I say this because I have also seen female basketball players sustain ACL injuries just as much as soccer players. For males sports I think it could not hurt added them into their daily warm-up routine.

Christian Glaser said...

Kaitlyn

Thank you very much for your comment. You are absolutely right, that a NMT warm up program will help female athletes as they progress through different levels of competition. Educating female athletes at an early age hopefully helps to incorporate the NMT programs into their daily warm up routine. Despite most studies for NMT warm up programs involve female soccer players, the results could be extrapolated to other sports as well in particular ones that involve sudden pivoting and jumping.

Jenna Robinson said...

I agree with Kaitlyn! I think that incorporating a NMT program for female athletes is a great idea because of their disadvantage in valgus stress to the knee. I also think that performing the program with males isn't a bad idea either considering ACL tears can happen in any athlete and since reducing the risk of injury is as simple as a different warm-up technique, why not?

Jenna Robinson said...

I agree with Kaitlyn! I think that incorporating a NMT program for female athletes is a great idea because of their disadvantage in valgus stress to the knee. I also think that performing the program with males isn't a bad idea either considering ACL tears can happen in any athlete and since reducing the risk of injury is as simple as a different warm-up technique, why not?

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