I try to do cross-training whenever I can to stay in shape. But I notice when I run, my knee hurts. If I stick to the elliptical and cross-country machines at the gym, I do okay. I really like running, so what could be causing this to happen?

Both types of exercises (running and machines at the gym) are repetitive in nature. But there’s one key difference. Running involves a ground force reaction. This refers to the stress and load through the ankle, knee, hip, and sacroiliac joint as the heel strikes the ground over and over again. Whereas the elliptical and cross-country equipment is low-impact, running is a high-impact activity.

Before continuing to aggravate your symptoms, it might be a good idea to get an accurate assessment of what’s going on. A physical therapist, chiropractor, or orthopedic surgeon can help you with this. A thorough exam will be done, including a history and some screening questions. The screening survey helps identify the possibility of a more serious cause of the problem such as a tumor, infection, or fracture.

The exam will continue with an evaluation of posture, range-of-motion, muscle strength, and joint stability. Special tests are usually performed to help identify impairment of the soft tissues around the knee.

Knee pain can be caused by disc problems, or hip, SIJ or ankle joint problems. The examiner will perform a regional interdependent exam involving both legs. Muscle flexibility, alignment, and exam of the joints above and below the knee will be done.

If there are no positive findings, the examiner will broaden the regional exam to include the sacrum and SIJ. There are numerous reliable and valid tests that can be done to isolate the exact location of the problem. Once this step is completed, then a specific treatment plan can be put into place to help you get back up and running.