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What's all the hype about preventing ACL injuries?

It is estimated that one-quarter of a million ACL injuries occur each year in the United States. As you know, players can be sidelined for months (sometimes longer). This is a concern to many people at all levels from high school to professional sports.

Preventing ACL injuries not only protects people from pain and suffering, it can also protect the pocketbook for the individual and for society. The fact is that many of these injuries are accompanied by damage to the surrounding tissues as well. The result is a weak knee that is at risk for future injuries and even the development of early arthritis.

Researchers at the University of Michigan (Ann Arbor) have performed a systematic review and meta-analysis on ways to prevent anterior cruciate ligament (ACL) injuries. They have confirmed that there is evidence to support the use of neuromuscular training programs -- enough evidence to give this approach a second look.

Presently, there is a wide range of risk factors that might contribute to ACL injuries. Addressing any of these factors that can be modified (changed) may provide some protection. For example, muscular strength, alignment, and flexibility are modifiable factors. The use of high-risk positions and/or techniques during sports play and lack of aerobic conditioning are additional modifiable factors that can be analyzed and modified.

Improving any one or all of these features may reduce the anatomic risk of ACL injuries. Age, genetics, and hormonal factors are nonmodifiable and may contribute to ACL injuries but cannot be changed to reduce the risk of knee injury.

Risk factors outside of the human body but still within our control are referred to as environmental factors. These include playing surface, use of footwear and/or braces, playing outside in bad weather.

The majority of evidence supported two directions for prevention of ACL injuries: neuromuscular re-education and educational interventions. Neuromuscular re-education includes addressing muscular strength, proprioception (joint perception of position), postural alignment, knee and ankle stability, foot position, core strength, and flexibility.

It turns out that training programs to address the anatomic risk factors do, indeed, reduce the risk of ACL injuries by as much as 50 per cent. Since the studies available did not analyze individual parts of training programs, this systematic review/meta-analysis was unable to pinpoint exactly which training interventions work the best. It does appear that more time spent in training and following the exercise programs carefully (compliance) provide a direct protective effect.

Reference: Joel J. Gagnier, ND, MSc, PhD, et al. Interventions Designed to Prevent Anterior Cruciate Ligament Injuries in Adolescents and Adults. In The American Journal of Sports Medicine. August 2013. Vol. 41. No. 8. Pp. 1952-1962.