Preventing ACL Tears
The Anterior Cruciate Ligament is extremely important to the competitive athlete. This ligament controls rotational forces in the knee. If this ligament is torn, sudden changes in direction become nearly impossible. Prevention of injuries to the ACL should be part of every athlete’s training regime.
Statistically, participants in women’s basketball and soccer are at a higher risk to tear an ACL. There are many theories as to why females are more at risk for this injury. Some of them include: a narrower notch width of the femoral head; the relative strength and muscle recruitment pattern of the hamstring muscles relative to the quads; high levels of estrogen; and, lack of proper training at a young age. Most experts believe that the incidence of ACL tears can be lowered by instituting some simple changes in the training of not only female athletes but all athletes.
General sports training should be centered around a properly periodized strength, flexibility, and aerobic conditioning program. The program should be planned so that the athlete progresses through specific phases of conditioning culminating in peak performance at the end of the sport season. The goal should be for the athlete to peak physically and mentally for the playoffs. The three basic cycles are: pre-season preparatory cycle; in-season cycle; and post-season cycle.
Coordination Improves Performance
Neuromuscular control of the knee during athletics is maintained by a complex interaction of the quadriceps and hamstring muscles. This includes both the muscles and the nerves that trigger the muscle contraction. Due to this non-contact ACL injuries may be a result of a breakdown in, or the lack of, the neuromuscular recruitment patterns necessary to prevent undue stress on the ACL.
The balance of power and the recruitment pattern of the quads and hamstrings have been shown to prevent ACL injuries. The quad muscles are an ACL antagonist, that is they place stress on the ACL when contracting. The hamstrings are an ACL agonist, removing ACL stress when contracting.
Due to this, if the hamstrings are excessively weak or inflexible they may not adequately protect the ACL during a strong quad contraction. Also, if the quad group is excessively strong, relative to the hamstrings, the ACL may be torn due to a lack of hamstring “protection.” ACL injury prevention should then focus on a balance in strength between the hamstrings and quads. It is recommended that the hamstrings should be 60 - 80% as strong as the quads. Also, proprioceptive exercises should be utilized to improve the neuromuscular recruitment patterns of the quads and hamstrings.
The off-season strength program should focus on the exercises that result in increased hamstring strength and flexibility as well as coordinative jumping exercises (plyometrics). During the first few weeks of training the emphasis should be on teaching proper jumping and landing techniques. The athletes should be taught to land on the balls of the feet with the knees flexed and the chest over the knees. They should be constantly reminded to avoid any excessive side-to-side or forward-to-back rocking of the knees upon landing. Valgus (inward) movement of the knee upon landing should also be discouraged. The athlete should also be taught how to land “softly.” This type of landing occurs when the athlete lands on the balls of the feet then rocks to the heels. Proper back posture should also be reinforced verbally.
Verbal cues should be used when observing the athlete during the jumps. Statements such as “light as a feather,” “recoil like a spring,” and “straight as an arrow” should be used to reinforce proper body mechanics. Proper body mechanics are the goal in the early stages of this type of program. Emphasis on power and explosion should only be instituted after the athlete performs the jumps properly.
Weight room activities should focus on exercises that improve hamstring strength and coordinated firing with the quad muscle group. Examples of these types of exercises are: hamstring curls, squats, power cleans, and dead lift. As with the plyometric exercises, proper technique should be taught prior to increasing the load. Be sure that the athlete’s hamstrings are 60 - 80% as strong as the quad muscles; that is, if the athlete can perform a 1-leg knee extension with 100 pounds they should be able to do a 1-leg hamstring curl with 60 - 80 pounds.
©2000 - 2009 David Edell
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Last Update for AthleticAdvisor.com: 10/24/2009 12:09:35 AM