Two of the main roles of your knee joints are to support your body weight and absorb the impact of everyday movements as well as more vigorous activities. For this reason, your knees are among the strongest joints in your body, but the almost constant strain they are under means they are susceptible to injury --- especially through repetitive activities like running.
Knee Anatomy
Your knee is a very complex joint because it is made up of three bones --- the thigh bone, the tibia in your lower leg and the patella, or kneecap. These bones are held together with very strong tendons and ligaments, the main ones being the posterior cruciate ligament and anterior cruciate ligament. Your PCL stops the tibia from moving too far backward out of the knee joint, while the ACL prevents forward movement. A layer of cartilage --- called the meniscus --- acts as a cushion between the knee bones and absorbs shock.
Outer Knee Pain
According to Sportsinjuryclinic.net, one of the most common knee injuries from running affects the iliotibial band, which is a strong sheath of connective tissue that runs from your hip, down the outside of your thigh and knee to the top of your tibia. When you run, this band tends to rub over the bones in the knee, causing friction and, as a result, pain in your outer knee. This condition is so common in runners that it is known as runner's knee. It flares up during and after a run --- especially if your route is hilly --- so rest and avoiding downhill running are recommended. Applying ice can also help reduce inflammation, and stretching after a run can prevent the iliotibial band from becoming tight, which exacerbates the condition.
Patella Pain
An aching feeling in the front of your knee can be a symptom of patellofemoral syndrome, which is caused by overuse of the knee joint and is, therefore, a common condition in runners, says Sportsinjuryclinic.net. It occurs when the patella starts to shift laterally, instead of directly up and down. This is often the result of overloading the joint as is the case when running, which places a great deal of pressure on your knees. Other symptoms can include swelling under the knee cap, pain and tenderness along the inner edge of the knee -- which gets worse when walking uphill or up stairs -- and a clicking sound when you bend your knee. Apply ice to your knee and, most importantly, rest until the pain disappears. A knee support may also help when you return to activity, as can strengthening your quadriceps.
Posterior Knee Pain
If you experience pain behind your knee and within the knee joint, you may have hamstring tendonitis. This condition is caused by overuse of the joint and repetitive actions such as running, which place pressure on the hamstring tendons, says PhysioAdvisor.com. The pain may get worse at the beginning of a run, when your tendons are still warming up, and your knees can become stiff afterward. Initial treatment involves applying ice to reduce inflammation, avoiding running until your symptoms ease, using a compression band and elevating your leg. Once your symptoms have decreased, stretching and strengthening your hamstrings can help prevent the condition from recurring.
