The incidence of knee injuries is quite high in runners owing to the repeated stress on the knee joint. The contributing factors for knee injuries while running range from overtraining, running on an uneven surface, following improper running techniques, to wearing unsuitable running shoes. The following write-up provides information on the medical conditions that could cause knee pain in runners.

The knee joint is a hinge joint that comprises the femur (thighbone), tibia (shinbone), and patella (kneecap). Quadriceps and hamstrings are the two opposing muscle groups that are located in the front and the back of the thigh respectively. While these bones provide structure to this joint, quadriceps and hamstring muscles help to flex, extend, and rotate the knee. Two types of cartilage are found in the knee. While the surface of the bones is covered by the hyaline cartilage, menisci are two disk-shaped pads of cartilaginous tissue that are present on the inner and outer edges of the shinbone. The menisci not only help to distribute the weight of the body, but also prevent friction between the femur and the tibia. The anterior cruciate ligament, posterior cruciate ligament, medial (tibial) collateral ligament, lateral (fibular) collateral ligament), and the tendons that are located in the knee provide stability to the knee joint.

Since running puts repeated stress on the knee joint, runners are often in the high-risk group for knee injuries. The range of motion of the knee joint would be impacted in an adverse manner in the event of damage to any of the anatomical structures of the knee. Under such circumstances, the affected individual would experience pain during any activity that involves the knee joint.

Knee Pain in Runners
Since the knee joint is a weight-bearing joint of the body, a knee injury is likely to affect one's ability to walk or run. It is therefore essential to identify the underlying cause of knee pain at the earliest. Here are some of the medical conditions that could cause knee pain.

Runner's Knee
Runner's knee, which is medically referred to as patellofemoral pain syndrome or chondromalacia patellae, is a common condition affecting runners, as well as others involved in high-speed sports which involve bending of the knees or actions that put stress on the knees. The kneecap is a triangular-shaped bone that glides within the V-shaped groove at the end of the thigh bone. If the kneecap is misaligned, the cartilage lining the underside of the kneecap could get damaged. This could give rise to knee pain.

Injuries can occur if a runner trains too hard to improve his/her performance, not giving the body sufficient time to recover. This condition is referred to as overtraining syndrome. Other factors that may be associated with runner's knee include:

◘ Muscle imbalance between the quadriceps and the hamstrings
◘ Tight hamstrings or quadriceps
◘ Over-pronation (excessive inward rolling of the foot after landing)

A person affected by this condition is likely to experience symptoms such as:

◘ Knee pain that worsens with exercise, and resolves with rest
◘ Pain around the kneecap
◘ Pain while going downhill or climbing down the stairs
◘ Frequent crackling noises from the knee
◘ Swelling and inflammation around the kneecap

Iliotibial Band Syndrome
Iliotibial band syndrome is a condition that is characterized by the inflammation of the iliotibial band, which is a thick band of fibrous tissue that starts at the iliac crest and runs down the outer part of the thigh and knee, before it attaches to the shinbone. This condition is more likely to affect runners who don't follow proper techniques while training. For instance, downhill running or running on one side of a crowned road could make a person susceptible to this condition. Besides overuse injuries, wearing worn-out shoes while running could also be a contributing factor. Stress on the knee could also be due to muscle imbalance or over-pronation.

Outer knee pain is one of the most characteristic symptoms of iliotibial band syndrome. The other associated symptoms include:

◘ Swelling and tenderness
◘ Pain while walking
◘ Pain while climbing the stairs
◘ Clicking sensation on the outer side of the knee

Meniscus Tears
The knee contains two crescent-shaped cartilaginous structures that are placed on top of the shinbone. These act as shock absorbers for the kneecap. The cartilage helps the thighbone to glide smoothly while the knee joint moves. Activities that involve bending and twisting of the knees are likely to cause a meniscus injury. Meniscal tears may also be attributed to an injury to the anterior cruciate ligament. Wear and tear of cartilage may also be associated with aging. Some of the common symptoms that are associated with meniscal tears include:

◘ Pain
◘ Swelling
◘ Difficulty in straightening or bending the leg
◘ Locking sensation in the knee

Patellar Tendinitis
Patellar tendinitis refers to the inflammation of the tendon that connects the kneecap to the shinbone. This condition often affects those who participate in sports that involve jumping, which is why it is called jumper's knee. However, this injury could also affect runners. Inflammation of this tendon occurs due to repeated stress. The symptoms associated with this condition include:

◘ Anterior knee pain that worsens with movement
◘ Swelling around the kneecap
◘ Crepitus (crackling sounds that might be heard while moving the knee)

The RICE approach (Rest, Ice, Compression, and Elevation) may prove beneficial in case of mild injuries, but medical help must be sought if the pain persists.
Precautionary Measures
While medical help must be sought by those who are affected by biomechanical problems or structural foot abnormalities, following certain measures can help to lower the risk of knee injuries while running. Here are a few self-care measures that can be followed to prevent knee pain.

◘ A warm-up session is extremely important as it prepares the body for any strenuous physical activity that you are planning to take part in.

◘ Refrain from running on surfaces that are hard or uneven.

◘ Training errors must be avoided. The intensity of the workout or any physical activity must be gradually increased.

◘ It is important to check that your foot is not imbalanced while you run. Foot imbalance will lead to knee imbalance, which in turn may cause knee pain while running.

◘ Muscle conditioning exercises should also be incorporated in the training.

◘ Wear the right kind of running shoes, keeping in mind the shape of your feet.
Though some people may experience knee pain while running due to poor biomechanics, pain in the knee could even be a self-inflicted problem in case of people who train too hard in order to improve their performance. While running is an activity that helps you burn calories, problems can arise if the right running techniques are not followed. So, do follow the aforementioned precautionary measures, and seek medical help if pain in the knee doesn't resolve soon.

Disclaimer: The information provided in this article is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.