Cycling is a very popular outdoor activity in Colorado and one of the most common reasons cyclists are seen at our Boulder Physical Therapy and Lafayette Physical Therapy clinics. Patellofemoral pain, or pain in the front of the knee, is the most commonly reported source of knee pain in cyclists. Cycling is typically thought of as a low impact activity for the knee, so why does knee pain continue to occur and what can done about it?
Research has shown that peak compressive forces in the patellofemoral joint while cycling are similar to those experienced during normal walking, and significantly lower than other activities such as ascending or descending stairs (when measured at a workload of 120 W and pedaling at a rate of 60 rpm). Peak compressive forces occur at about 90 degrees of knee flexion and can be significantly augmented by increasing workload or lowering the saddle height. However, compressive forces do not change significantly at higher or lower pedaling rates when kept at the same workload. During cycling, the knee is flexed more than 30 degrees for much of each revolution of each pedal stroke. Compounded by the high volume of revolutions performed during each ride, high compressive forces and small errors in biomechanics can lead to symptom provocation.
There may be simple ways to quickly reduce compressive forces and manage pain including increasing the saddle height or choosing an easier gear to pedal at a higher cadence. If these tactics do not help, then Physical Therapy should be considered. Impairments off the bike such as range of motion and muscle imbalances in the leg can be addressed to improve alignment of the knee while cycling. In summary, joint compressive forces are one factor that can be modulated by changing cycling technique, however, the individual also needs appropriate strength and control of the knee position for an optimal cycling experience.
Ericson MO, Nisell R. Patellofemoral joint forces during ergometric cycling. Phys Ther. 1987 Sep;67(9):1365-9. doi: 10.1093/ptj/67.9.1365. PMID: 3628491.