KNEE STABILITY IS IMPORTANT FOR ALL ATHLETES, PROFESSIONAL OR RECREATIONAL.
www.livestrong.com says it best in their article on knee stability:
There are three major factors that make professional and recreational athletes susceptible to anterior cruciate ligament, otherwise known as ACL, tears: poor form, muscular imbalance and knee instability. Deciding which factor was the primary cause of the injury often leads to a chicken or egg question. Was the knee unstable due to a muscular imbalance? Did the muscular imbalance have an adverse effect on form? While these questions may be difficult to answer, most coaches and athletic trainers agree that a knee stability training program may help prevent injuries.
Preventing Joint Laxity
The popularity of yoga as a fitness activity and Cirque du Soleil as a form of entertainment has inspired some people to become contortionists. Unfortunately excessive flexibility leads to joint laxity, joint laxity causes instability and instability can cause injuries. In fact, while trainers once believed that static stretching was an essential part of the athletic warm-up, many coaches are finding that this type of pre-event flexibility training can actually weaken the muscle, which can impede performance. Static stretches are stretches that are held for 20 to 30 seconds. Although they are designed to increase muscle length, length without strength might lead to injury.
Coaches such as sports medicine expert Vern Gambetta suggest that static stretching should be performed only after the activity, and that flexibility should be balanced with strength training exercises.
Adductor Strength for Inner Knee Stability
An ACL tear is often accompanied by a tear or strain of the MCL, or medial cruciate ligament. Instability of the muscles supporting the medial knee can make you more susceptible to this injury. Again, excessive straddle-type stretching without adequate adductor or inner thigh strengthening may cause this problem.
Lie on your side with your bottom leg straight. Bend your top knee, and place the foot flat on the floor in front of the bottom leg. Inhale to prepare. As you exhale, squeeze your inner thigh and lift the bottom leg from the floor. Perform three sets of 15 repetitions on each leg. If you have a pair of ankle weights, perform three sets of 12 repetitions.
Hamstring Strength for ACL Support
Many people have a muscular imbalance between the hamstrings and quadriceps. Hamstring weakness is one of the many causes of ACL injury. Hamstrings are responsible for leg flexion, whereas the quadriceps are responsible for leg extension. In the event of a fall, the knees should bend to protect the ACL. However, if hamstring weakness prevents the leg from bending, the ligament may become unstable, and the leg might hyper-extend.
The stability ball hamstring bridge is one of the most effective hamstring exercises, because it promotes balance and proprioception while strengthening the hamstring muscles. Proprioception is used to describe your awareness of your body position. Many knee injuries are caused by impaired proprioception.
Lie on your back with your knees bent and your feet on the stability ball. Separate your feet a hip width apart. Lift each vertebra from the mat, until your spine is in a bridge position. Remain in the bridge as you straighten and bend your legs for eight repetitions. Perform three sets.
The leg abductors, which are located on the outer side of the leg, have an indirect influence on knee stability. Weak abductors can lead to IT Band Syndrome, which causes pain down the side of the leg. This pain can alter the athlete’s gait, which can lead to poor form. When form is compromised, injuries can occur.
Lie on one side with the bottom leg bent and the top leg straight. Keeping the top knee facing straight ahead, raise the leg to hip height. Do three sets of 15 repetitions. If you are adding ankle weights, do three sets of 12 repetitions.
The Vastus Medialis
The vastus medialus is the lowest portion of the quadriceps muscle. It is responsible for the last 10 percent of leg extension. Because it is located directly above the knee, it has a direct influence on knee stability. This muscle can be trained with one legged-mini-squats.