Running is a popular form of physical activity for many Americans, at all ages of the life course. It is a convenient type of exercise – something you can do alone or with others, at whatever time of the day best suits your schedule. You can also accomplish a lot of cardiovascular fitness by running regularly in only a short period of time.

Unfortunately many people who participate in running regimens, both highly seasoned athletes, and those new to the sport, experience knee pain at some point in time. Knee pain during and / or after running can be caused by a variety of different conditions. Here are seven of the most common reasons that runners may experience knee pain:

1. Meniscal tear

There are two meniscus in each knee. A medial meniscus and a lateral meniscus. They are both shaped like a C and function as shock absorbers in the knee joint. They provide a cushion to the knee. When a meniscus tears it produces a sharp pain, swelling, and clicking with occasional locking of the knee joint. The pain occurs with activity that involves a plant and a twist of the knee and it is very activity specific.

2. Patellofemoral syndrome

This is a condition that involves the knee cap region of the knee. There are several different causes of patellofemoral syndrome. Different causes include early osteoarthritis, a patella that tracks abnormally or a patella that is tilted laterally. The pain is dull in quality. Typically swapping does not occur with patellofemoral syndrome. Symptoms worsen with climbing or descending stairs and hills.

3. Patellar tendonitis aka Jumper's Knee

The patellar tendon connects the knee cap (patella) and to the shin bone (tibia). The patellar tendon can get inflamed. When this occurs it is called patellar tendonitis. The symptoms are a sharp pain located in the region of the tendon. Activity that intensifies the pain is jumping and running.

5. Osteochrondritis dissecans aka OCD

OCD or osteochrondritis dissecans is a condition where the bone near the surface of the knee joint dies. The exact etiology of the condition is unknown but it is thought to occur from micro trauma: repetitive activity to the knee. The pain is sharp and typically produces popping and locking. The pain is typically constant through the activity.

6. Stress fractures

Stress fractures cause a sharp and very localized pain to the knee. Localized swelling is common in the region of the stress fraction. Pain may also occur at night. The pain from stress fractures tends to worsen with activity. They usually occur since a sharp increase in activity. Stress fractures are comparatively common in runners who increase their weekly mileage more than 10% per week.

7. It band tendonitis

The IT or iliotibial band is a structure that is located on the outer side of the knee joint. It can become inflated with repetitive activity. It produces a sharp pain with flexing of the knee. Typically there is no swapping in the area but the pain is very localized. Pain occurs with flexing of the kneecap.

As is discussed in the examples above, there are a number of different reasons why you may experience pain in your knees while running. If you are experiencing knee pain from running or for any other reason, it is advisable that you connect with a board certified orthopedic surgeon for a diagnostic exam and medical advice. It is smart to seek out medical treatment before a minor injury turns into something more chronic and serious.

While knee pain while running may be common, it is not normal or inevitable. There are many things you can do to try to prevent running induced knee problems and also to heal from knee pain due to running.