Anterior knee pain is a common injury for cyclists (read my post on cycling and knee pain). This injury is also present in the general population, typically amongst growing children and teenagers. Overall it affects 25% of the population at some point in their life.
Anterior knee pain occurs when the quadriceps muscles are unable to support the mechanical requirements placed upon them through activities in daily life (such as climbing up or down stairs) or sport and recreational activities (such as cycling or mountain climbing).
Mechanical failure of the quadriceps muscles results in compression of the underside of the knee cap (the cartilage) onto the thigh bone (femur) below. This results in pain and inflammation in this area and makes loading of the knee and knee cap as well as bending of the knee, painful. The result is a reduced ability to participate in previous activities, especially sport.
In cyclists, anterior knee pain is commonly created as a result of too rapid or too many increases to a training schedule, but, importantly, research also shows that anterior knee pain can also be due to your bike’s saddle height being set incorrectly.
From the research, it appears that the height of your bike’s saddle has an influence on the amount of compression that is placed through the knee cap, thus influencing the development of anterior knee pain or not. The lower the height of your saddle, the higher the compressive forces on your knee cap and the greater your risk of developing anterior knee pain.
Apparently there are a number of recommended ways to set your saddle height correctly, but not all are supported by scientific research. According to a research review published in 2011, the researchers determined that using the knee flexion angle method was the preferential method to determine the correct saddle height for your bike and that when using this method, your knee angle should be set at 25-30 degrees. Another benefit of this saddle height position is that it optimizes your oxygen consumption when cycling at a steady pace.
Now, how do you go about setting your bicycle saddle height according to the knee flexion angle method with the knee angles set between 25-30 degrees?
- Firstly, you need to be seated on your bike and remain seated throughout the process.
- Secondly, you need to place your foot on the pedal with your ankle in the neutral position and keep it neutral especially when you’re checking your knee angle. If you don’t keep your ankle neutral, and you place your foot into plantar flexion (toes facing downwards towards the earth), the greater your degree of plantar flexion, the greater you knee flexion angle will become and you will not have set your knee angle correctly.
- The ball of your foot should be positioned slightly anterior (i.e. forwards) to the midpoint of your bike’s pedal. This improves hamstring function.
- Once all the above are in place, then, drop one pedal to the 6 o’clock position. The knee joint angle of this leg should be bent (flexed) to 25-30 degrees when the pedal is at this 6 o’clock position. To accurately determine this angle, you may need a joint goniometer or someone with you who is good at judging angles. It may be useful to go see your sports physiotherapist to get them to help you set up your bike correctly.