But injuries can also develop over time, from repetitive stress that damages cartilage and other soft tissue in the knee joint. One common overuse injury is patellofemoral stress syndrome (often called runner's knee), in which the cartilage of the patella (kneecap) becomes irritated, resulting in pain and inflammation. Iliotibial band syndrome (ITBS) is another source of pain for athletes. The IT band is a stretch of fibrous tissue that runs down the outer thigh and knee; running and other activities cause the band to repeatedly rub against the outside of the knee joint, which may lead to inflammation and pain at the outside of the knee. ITBS is usually seen in long-distance runners and cyclists, but can occur in soccer players, skiers and weight lifters. Reducing activities can help ease the pain of any overuse injury, while some may require physical therapy or other medical treatment.
If people with bad knees switch to safer activities, should they still try to slow down?
It depends on the injury. Unfortunately, this is one of those gray areas where you have to say, "What was the injury to knee, and how bad is it afterward?" That will give you an idea of what sort of activities you can still do. A doctor, certified trainer or physical therapist can help you build an appropriate exercise regimen.
Your immediate post-injury rehab - and long-term dedication to supplemental conditioning exercises - also make a big difference. A lot of injuries seem to be due to weakness in certain muscles, such as those of the hips and lower back, and the hamstring and quadricep muscles of the thigh.
