What is the ACL?
In medical terms, the anterior cruciate ligament (ACL) is the primary restraint to the anterior displacement of the tibia on the femur at all angles of the knee flexor.
This means that when the ACL is injured, the shinbone can slide forward on the thighbone, causing the knee to “give way.”
The ACL is one of a pair of ligaments in the center of the knee joint that form a cross, and this is where the name “cruciate” comes from. There is both an anterior and a posterior cruciate ligament (PCL). Both of these ligaments function to stabilize the knee from front-to-back.
What causes an ACL injury?
An ACL injury is usually caused by sudden, abrupt change in the force to the knee. This can occur during an unexpected cutting move made during a sporting activity, or during a landing from a jump during a basketball game. Most ACL injuries occur in a non-contact setting and do not involve a collision with another player.
What does an ACL injury mean to an athlete?
When an athlete injures the ACL, it may mean losing an entire season of play. If the injury is severe enough, it could also lead to surgery resulting in long-term rehabilitation, a possible loss of scholarship funding, and emotional and mental impairment affecting the athlete’s quality of life. ACL injuries could additionally be a lifelong potential for future arthritis in the injured joint.
Why does it occur more frequently in female athletes?
ACL injuries typically occur at a 4 to 6 times higher rate in female compared to male athletes. This may be associated with females being more quadriceps dominant. Another factor may be the decreased neuromuscular performance, and the increased ligamentous laxity during menstrual cycles from the fluctuation of female hormones (i.e. estrogen, progesterone, relaxin). Another possible cause is the decrease in passive and active knee stability in female athletes. A study in the New England Journal of Medicine found that there are differences in the leg ailments of males and females where females have an increased rate of knock-knee (valgus deformity). The intercondylar notch-width is smaller in females, thus creating less space for the movement of the ACL, resulting in increased risk of injury.
The National High School Sports-Related Injury Surveillance Study, currently in its fourth year of online data collection spear-headed by Dr. D. Comstock, has found that approximately one ACL tear occurred in every 15,000 times an athlete practiced or competed. On average, athletes are eight times more likely to suffer ACL injuries in competition than practice. Data was collected from a national sample of nine boys and girls high school sports (including football, soccer, basketball, wrestling, baseball, volleyball, and softball).
How to prevent ACL injuries
A few of the more important ways to prevent ACL injuries include:
1) Plyometric movements to improve lower body coordination, and endurance
2) Agility drills to improve lower body agility
3) Core stability. The core is the first to fire/activate, therefore stabilizing it allows the head and limbs to move appropriately and safely
4) Dynamic neuromuscular and proprioceptive training – these are shown to increase knee stability and decrease knee injury rates in athletes
5) Strengthening with weight resistance:
a. Improves quadriceps to hamstring strength ratio – especially in females
b. Sport-specific training
c. Strengthen the surrounding musculature around the hip, knee, and ankle
6) Single-leg strength – F.I.T.
a. Fierce glute function (especially the medius)
b. Incredible 1-leg strength
c. Terrific deceleration capabilities
Six super ACL prevention exercises shown by Sam Patierno, CSCS are presented on this website under the “Schools” section.
Dr. Robert Silverman is a Doctor of Chiropractic who specializes in sports injuries and nutrition. He can be reached at 914-287-6464.
Sam Patierno is a personal trainer, He can be reached at firstname.lastname@example.org