By Holly Jacinda Silvers, MPT

ACL Anatomy
The ACL is found deep in the knee join and acts together with the PCL (posterior cruciate ligament) as the primary stabilizer of the knee joint. The ACL connects the tibia (shin bone) with the femur (thigh bone) and helps to prevent excessive forward movement and inward rotation of the shin on the thigh bone during agility, jumping and deceleration activities.

Are you at Risk?

The configuration of the knee makes the ligaments and the cartilage prone to injury with any contact to the knee, or often with just the force of a hard muscle contraction-like performing a quick change of direction when sprinting or a very sudden deceleration maneuver. You can also incur an ACL injury with an improper landing technique; landing with a straight knee and hip on a flat foot.

The four common risk factors include anatomy, environment, hormones and biomechanical. In terms of anatomy females demonstrate a wider pelvis, greater lower leg rotation and more inward caving of the knee. Athletic footwear is designed to allow the athlete to cut and pivot quickly. However, if friction is between the shoe and the playing surface is too high, you can increase the force on the lower leg. There is a fine line between performance enhancement and increasing risk of injury. When it comes to hormones because receptors for estrogen, progesterone and relaxin have been found to physically exist on the ACL ligament there have been studies on the female menstrual cycle to see whether or not the monthly fluctuation in estrogen and progesterone can be linked to an increase in ACL injury. As of yet, no consensus has been reached.

Biomechanical risks do seem to have merit. Intervention programs designed to alter strength, balance and joint awareness have been highly effective in decreasing the number of ACL injuries.

ACL prevention programs tend to be sport specific and focus on core stability, flexibility, trunk strength, lower body strength, balance and power. One program that has experienced great success is the PEP Program (Prevent injury, Enhance Performance) from the Santa Monica Orthopedic and Sports Medicine Research Foundation. It is a highly specific, 20-minute field training session that replaces the traditional warm-up. Here is one exercise included in the program:

Walking Lunge:

Lunge forward leading with your left leg. Drop the back knee straight down with your front knee over your ankle. Keep your shoulders over your hips and control the motion to avoid letting your front knee cave inward. If you can’t see your toes on your leading leg, you are doing the exercise incorrectly. Step forward with the right leg and repeat. Complete 30 repetitions on each leg.