Patients often assume that cycling, considering that it is a non weight bearing exercise, absolves them from experiencing any knee pain. This is simply not the case. While cycling does not involve the joint impact and axial loading that other activities deliver it can precipitate knee pain. Knee pain while cycling is a condition typically more of a cumulative nature or a repetitive stress injury. The most common condition to cause knee pain in cyclists is Chondromalacia Patella, or Patellofemoral Syndrome. Chondromalacia is a condition of softening or a “breaking down” of the cartilage behind the patella or knee cap.
Causes of Chondromalacia Patella may include muscular imbalances in the lower body which would cause the rider to utilize one muscle group more than the other thus creating a biomechanics stress or tracking disorder of the knee cap. If those muscles do not function in unison and one or more groups dominate another the biomechanics of the knee joint are thrown out of alignment. It pulls the patella out of the normal position and results in a tracking disorder or an abnormal wear and tear of the bone, and soft tissues associated. Another condition that may be overlooked are true leg length discrepancies which results in essentially the same biomechanics and muscular imbalances I noted above.
Of course the bike itself, if not designed or situated properly for the rider will cause undue stress on the low back, hips and knees. Seat positioning is key for proper extension and flexion of the hips, knees and ankles. Although the conditions mentioned here are usually only soft tissue in nature and typically take time to manifest into symptoms, if not corrected may lead to an early onset of osteoarthritic changes within the joint.