This question is actually very common. One of the likely sources of the pain is the kneecap or patella. Every step you take walking or running, your patella “tracks” in a groove at the end of your thigh or femur and the movement of the patella can become altered. Other potential sources of the pain, besides the kneecap, would be related to a tendon. The common tendons involved are the iliotibial band, the hamstring, and the patella tendon.
Other causes of knee pain can be related to “doing something wrong,” or making errors in your training. The desire to increase either intensity or duration too quickly can be an issue. Remember that muscles need to be able to respond to the forces that are being placed upon them. If you increase the loads by running more or harder, the muscle will adapt by getting stronger. However, this requires a gradual increase with time to recover between efforts. Too often people try to run every day or nearly every day and the body does not have a chance to recover. I recommend running every other day for the first month of your training, then increasing to no more than five running sessions per week. Increase your total running time no more than 10-20% per week.
Knee pain associated with mileage increase can also be caused by a lack of strength in key areas. Running itself is not sufficient to build the necessary strength in the legs, hips, and core. Targeted strengthening of the buttocks muscles (mainly the gluteus muscles) and quadriceps muscles, as well as strengthening the core, are often needed. The key is to first identify the strength deficits and then correct them before increasing mileage.
In summary, to prevent knee pain don’t increase mileage or intensity too much and make sure you’re strengthening muscles that support the knee and the core muscles.
Dr. James Kinderknecht is a sports medicine physician at Hospital for Special Surgery. He has spent the past 20 years caring for athletes of all ages and levels. Dr. Kinderknecht enjoys promoting the positive benefits of physical fitness to high-level endurance athletes as well as individuals who want to begin an exercise program.