Preventing Knee Injuries

The knee is one of the most injured regions of the body. Women are more prone to knee injuries than men, especially when practicing high-impact sports that involve cutting and jumping. The reason is still unclear, but researchers believe that women tend to have knee motions that make them more susceptible to injuries. Recent studies have found that there is a difference in the way sensory information is processed by the nervous system in men and women, which could explain the differences in injury rates.

Unfortunately, there is not much we can do about it. However, we may be able to prevent injuries by practicing proper technique, especially when landing. In addition, adequate muscle balance and proper range of motion are fundamental components of body alignment, which can influence joint stability. When a muscle is stronger than its antagonist[1], for example, it makes the joint move through an unusual path. If this erroneous pattern continues in the long run, it may lead to further adaptations in other joints and muscles, exacerbating the imbalance. This results in poor neuromuscular control and joint stability, increasing the risk of injuries.

Remember that because everything is connected, a misalignment in the hip or foot region could easily be transferred to the knee area. Common static postural problems include flat foot (foot and ankle turning inward), knee valgus (knee collapsing inwards), anterior pelvic tilt (hip bones shifting forward), and lack of flexibility of thigh muscles. These conditions tend to place excessive stress on muscles and connective tissues of the knee joint. In addition, weak hip and leg muscles are usually unable to stabilize the knee joint during movement, allowing the knees to collapse inward or outward. When the knees tend to move inward, it may indicate tightness of the calf, TFL/IT-band[2], and inner thigh muscles, as well as weakness of the shin and gluteus group muscles. Knees moving outward, on the other hand, may indicate tightness of the lateral part of the calves, piriformis[3] and biceps femoris (lateral part of the hamstrings), and weakness of the inner thighs and medial hams.

The following are the most common knee injuries:

• Patellar tendinopathy (jumper’s knee) is an overuse injury caused by repeated stress on the patellar tendon. This stress creates micro tears on the tendon, which may progress to degenerative changes or inflammation. It is usually associated with poor flexibility of quads and hamstrings, overtraining, and jumping on hard surfaces.
• Iliotibial band syndrome (runner’s knee) is also an overuse injury characterized by the inflammation or irritation of the IT-band, a tendon located on the outer aspect of the thighs. It is commonly linked to the lack of flexibility of the TFL muscle, weakness of the gluteus medius, and abnormal gait when running.
• Anterior Cruciate Ligament injury (ACL sprains or tears). Neuromuscular imbalances have been noticed to increase the risk for acute injuries such as the rupture of the ACL. It is more common in women than men, probably because of differences in the biomechanics of landing, which may be aggravated by insufficient neuromuscular control. Injury usually occurs during landing (from jumping or running) or when changing directions with the foot planted on the floor (cutting).

Prevention

In order to prevent injuries, it is fundamental to maintain muscle balance and proper range of motion of the knee. This means strengthening weak muscles and stretching tight ones. Below, I included a sample routine composed of isolation (single joint) exercises that targets the muscles of the outer and inner thighs, as well as the glutes and the hamstrings. Perform two sets of 12 to 15 repetitions for each exercise. In addition, I presented four static stretches to improve flexibility and range of motion of common problem areas. Perform two to four repetitions of each stretch, holding the position for 30 seconds until the point of mild discomfort.

References

Clark, M. et al. NASM Essentials of Corrective Exercise Training. Baltimore, MD: Lippinicott Williams & Wilkins. 2011.

“Knee Injuries in Women Linked to Motion, Nervous System Differences.” Science Daily. Available at http://www.sciencedaily.com/releases/2012/04/120417125629.htm. Access in April 2012.

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