Wednesday, November 14, 2007

Neuromuscular Training Reduces ACL Injuries

Nearly everyone is aware that female athletes are far more susceptible to anterior cruciate ligament injures than are their male counterparts. This is especially true for women soccer players. Researchers have been examining why this is and trying to develop programs to reduce injury risk. Dr. Timothy Hewett of the University of Cincinnati recently published an analysis of various neuromuscular training programs and their ability to reduce the rate of ACL injuries in female athletes. The article appears in the March 2006 issue of the American Journal of Sports Medicine.

The researchers closely examined the results of six different studies. Each study used similar neuromuscular training programs designed to prevent ACL injuries in female athletes. Four of the studies used soccer players and the other two focused on team handball players. The analysis showed that the training programs did indeed reduce ACL injury occurrence. In two cases, the incidence of ACL injury during the competitive season was reduced by 70-75%! That’s an impressive when one considers the extreme number of female athletes who are sidelined due to a torn ACL.

What sorts of exercises are included in a neuromuscular training program? Dr. Hewett’s analysis shows that there are four key activities: 1) plyometrics, 2) technique feedback, 3) balance training, and 4) strength training.

Plyometric training includes explosive movements such as hopping, jumping, bounding and depth jumps. Each of these activities involves rapid changes in direction. Plyometric training improves both the strength of the muscle and its ability to respond to rapid changes in direction. This, in turn, provides greater muscular stability to the knee joint during game conditions. An excellent overview of plyometrics and specific exercises can be found at the University of Oregon site (click here).

Plyometric drills should be performed using technique feedback from a trainer or coach. It is important that the exercises be executed with proper technique in order to train the neuromuscular system to activate the proper muscles in the proper manner to stabilize the knee. The trainer can help the athlete emphasize correct landing technique and make them realize body positions that make them susceptible to injury. It is especially important for the trainer to emphasize landing with the knee flexed and positioned over the foot. The trainer can also tell when the athlete is fatigued and not executing proper technique.

Balance training is important to improving core stability. Single leg stability exercises using balance training devices and balance boards can improve core balance. These exercises are made even more effective when feedback emphasizing proper technique and body position is provided by a trainer. Here, the goal is to train the neuromuscular system to support the knee during periods where the athlete is unbalances.

The last component of a neuromuscular training program is strength training. This should involve high-volume, low-intensity exercises. It is also important to strengthen the hamstring group as well as the other muscles that flex and extend the knee. Greater muscular strength will support the ligaments that stabilize the knee and reduce the risk of injury. It is important to point out that strength training alone dies not seem to reduce injuries but when it is combined with the other components of a neuromuscular training program, the results are impressive.

In concluding their analysis, the researchers recommend that in order to reduce ACL injuries in female athletes, three key principles should be followed:

1. Plyometric, balance and strength training should be incorporated into the training program.
2. The training sessions should be performed at least two times per week.
3. The duration of the program should least at least 6 weeks and should be used pre-season and in-season.

The bottom line of this study is that there is hope for female athletes. A program of neuromuscular training performed during pre-season and continued through the competitive season can reduce the risk of an ACL injury.