Due to its highly repetitive nature, cycling can injure knees. The actual damage done to the knees is not really traumatic; however, the knee usually gets injured in small doses until there is a major injury.
The most common pain complaint from cycling is lower back strain. This will be addressed in a future article. Back pain tends to abate more quickly than knee pain. Knees therefore stop cyclists from cycling for longer periods of time than backs.
A little about the knee joint.
The knee joint is essentially a hinge and unlike the ankle, hip or shoulder joint works on a single plane and does not respond well to lateral and medial movements.
The joint is held together by a web of tendons and ligaments that have limited blood flow. By implication, knees take a while to heal.
The joint does a lot of work during a bike ride. Supposing that you have an average cadence of 90 rotations per minute, an hour ride will cause 5400 rotations, a two hour ride, 10 800, and a three hour ride, 16 200 rotations. Multiply that out per sessions per week or month and you understand just how much the joint has to work.
Things on your bike that can hurt you.
Excessive external rotation of the hips will cause knee issues. Until the hips become more stable it might be an idea to move the feet slightly more apart on the pedals in order to look after the knees.
ITB issues also demand a slightly foot out position.
People with flat foot arches can experience a type of forefoot pronation as they cycle. The result of this is knees that fall inward whilst they cycle thus putting pressure on the medial collateral ligaments. Attention needs to be paid to both foot position and also making sure that the foot is correctly supported. Pearl Izumi makes a brilliant product in this regard and we have seen great results from it.
A number of bike shops are happy to sell cleats and shoes to people and then leave the cyclist to set the cleat up by themselves. If your feet naturally turn out when you sit then that is how your cleat needs to be set up. The result of your cleats forcing your foot into an unnatural position is undue pressure on the knee.
Most cyclists do well on pedal systems that allow for a degree of heel float. Most Shimano pedals allow for about 7 degrees of float. Your knee will do well with those seven degrees provided that the cleats have been set up properly.
Fore and aft positioning of the cleat is also important. It is possible to place undue stress on the knee by placing the cleat too far back.
We have had people who have strained their knees by having to twist their feet too violently to get out of their pedals. It is always best to set the pedal so that it is easy to exit the foot.
Saddle height is extremely tricky. Get the saddle too high and you can put strain on the Hamstrings and Iliotibial band. Get it too low and you place the Femoral head and knee cap under pressure. This setup will increase cartilage wear and tear as well placing strain on the Anterior structures of the knee. It is impossible to do a proper bike setup without understanding what is going on in the knee first!
Saddle Fore and Aft Position.
The ideal saddle position on a Mountain and Road bike will balance out usage of the glutes and hamstrings on the one side and the quads on the other. The same rule does not apply to time trial bikes. A separate article has been written to explain how this is setup.
Handle Bar position.
Care needs to be taken that the cyclist is not too stretched out across the bike. Doing this will cause the hips to rock forward causing undue pressure to be experienced from the front of the saddle. This will also cause the leg to overextend and thus place pressure on the lower back.