Q: Are knock knees a problem for exercise?
A: They can be. People who are very knock-kneed are at increased risk for a variety of injuries when running or doing other high-impact exercise or activities. Many people are somewhat knock-kneed, and depending on the severity, this can put added strain on the hips, knees, lower legs, ankles, and feet. In runners, being knock-kneed can make their feet roll inward too much (overpronate).
To see if you are knock-kneed, stand straight with your feet hip-width apart and look in a mirror: If your kneecaps turn inward and are not aligned with the center of your feet, you have some degree of knock knee.
If you have knock knees (or, in contrast, are bowlegged) and are thinking about running or starting another high-impact activity, talk to a doctor or physical therapist. You may need orthotic inserts for your shoes or a special exercise program. You may be advised to avoid high-impact exercise altogether. If so, cycling, walking, and swimming are safer alternatives.