Thursday, March 4, 2010

Cycling And Knee Pain

With the OCBC bike race this weekend, both our clinics have been seeing quite a few cyclists this past week and so I thought I'll do a write up on the combination of cycling specific factors that can cause ailments/ grief to your knees.

These factors can often be divided into cycling specific reasons, bike specific and cyclist specific reasons. Cycling specific causes are mainly due to suddenly increasing distances, intensity, hills, using heavier gears and lower cadences while bike specific reasons are likely to occur when radical changes are made to your saddle height, setback and/ or cleat position.

I will elaborate more on the cyclist specific factors that can cause your knee injuries as this often happen due to your own individual make-up and biomechanics, i.e. intrinsic rather than extrinsic reasons.

The first cyclist specific factor that can cause your knee pain is usually due to anatomical differences such as a leg length discrepancies (bearing in mind most of us will have this). Most often though, I've found that most cyclist tend to favor one leg over the other. This is usually the leg with your thigh closest to your seat post when you are pedaling which partly explains why knee pain seldom affects both knees equally.

All of us have had falls, knocks, scrapes and other injuries which may lead to us subtly changing the way we move and so previous injuries (cycling related or not) can also be a contributing factor to causing knee pain. This is especially more so when we decide to ride more than normal at the start of the season or when we have a new bike etc.

The cumulative effect of the two reasons mentioned above can then upset the forces your knees have to deal with while pedaling. Each pedal stroke bends and straightens the knee joint but it should never straighten your knees fully (if it does, your saddle is too high). The push (straightening) phase starts when your knees are bent at about 110 degrees, and the knees start to bend again at about 35 degrees (when you start the pull phase of your pedal stroke). Your muscles and tendons around the knees are the direct shock absorbers for the forces transmitted there. Hence overused or tight muscles which arise from repetition (with you turning the pedals over and over again) can contribute to increased forces to your knees.

The accumulation of excessive loads over time can exceed your body's ability to dissipate forces which can lead to damage if not given a chance to recover, which then leads to injury (hence the need for rest days).

The good news is the vast majority of these cycling specific knee pain improve quickly (with non-operative intervention) with correct identification and treatment of the cause of your pain, something which we at Physio and Sports Solutions are good at.

Please come look for us if you need. And all the best to all of our patients who are taking part in the race.

*Thanks to my patient KM for allowing me to take a picture of his knees.

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