The Anterior Cruciate Ligament (ACL) is one of a pair of ligaments in the center of the knee joint that forms a cross.  There is both an anterior and posterior cruciate ligament (PCL).  Both of these ligaments function to stabilize the knee from front-to-back motions, with the ACL’s primary function to restrain anterior displacement of the tibia on the femur.  It stops the shinbone from sliding forward on the thighbone, causing the knee to give out.  Injuries occur when the knee is straightened beyond its normal limits (hyper-extended), twisted, or bent side to side.  Typical situations that lead to ACL injuries often occurs during sports, such as, basketball, football, soccer, skiing, and gymnastics, where you change direction rapidly, slowing down and accelerating rapidly, or landing from a jump.  Another way to tear your ACL is from impact, when your foot is firmly planted on the ground and a sudden force hits your knee while your leg is straight or slightly bent.  Also, losing muscle tone in your legs (from aging or inactivity) will weaken the stability of your knee, increasing the risk of ACL tears.

Female athletes have up to 8 times the amount of ACL tears compared to male athletes for several reason, but a major factor is because the imbalance in muscle strength between the hamstring muscles compared to the quadriceps. Girls tend to be more quad dominant compared to their hamstring, which is usually not strong enough in relationship to handle their activities, especially in sports like soccer.  When you kick a soccer ball, your quad muscle forces the knee into extension and your hamstrings work eccentrically at the end to protect the knee from hyperextension.  Also, your hamstrings work to control the pressure when you change direction, if your hamstring muscles are weak compared to your quads, you will tear your ACL. Below are exercises that will strengthen the muscle surrounding the knee joint and help decrease the chance of ACL tears.













Grade I sprain
* The fibers of the ligament are stretched, but there is no tear.
* There is a little tenderness and swelling.
* The knee does not feel unstable or give out during activity.
Grade II sprain
* The fibers of the ligament are partially torn.
* There is a little tenderness and moderate swelling.
* The joint may feel unstable or give out during activity.
Grade III sprain
* The fibers of the ligament are completely torn (ruptured)
ACL Avulsion: the ACL is torn away from the upper leg bone or lower leg bone.
ACL Avulsion Fracture: the ACL is torn away from the leg bone with a piece of the bone.
* There is tenderness (but not a lot of pain, especially when compared to the seriousness of the injury).
* The ligament can not control knee movements. The knee feels unstable or gives out at certain times


1 Increase muscular endurance and stability of muscles surrounding the knee and hip joints.


2.Extra emphasize on the posterior chain muscles to help decrease muscular imbalances between quads and hamstrings

3.Increase overall muscular strength of muscles surrounding the knee and hip joints.