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Positioning the Saddle Height on Your Bike Correctly to Reduce Anterior Knee Pain

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.

cycling, seat height, knee pain
” Bradley Wiggins, col d’Eze paris-Nice 2012″ by Dacoucou under Licence CC BY 3.0

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.

 

Reference:

Bini R., Hume P.A., Croft J.L. (2011).  Effects of bicycle saddle height on knee injury risk and cycling performance.  Sports Medicine, Jun 1;41(6):463-76. doi: 10.2165/11588740-000000000-00000.

 

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How Strong Quadriceps Muscles Help with Anterior Knee

Anterior knee pain is a very common cause of knee pain in people across all ages. Some people may also know it as patello-femoral syndrome.

"Image illustrating the areas affected by w:en:Patellofemoral pain syndrome" by BodyParts3D/Anatomography under Licence CC BY 2.1
“Image illustrating the areas affected by w:en:Patellofemoral pain syndrome” by BodyParts3D/Anatomography under Licence CC BY 2.1

Anterior knee pain (or patello-femoral syndrome) is pain that is found in the front of the knee.

Anterior knee pain will commonly get worse when you use stairs.  Going downstairs is generally more painful than going upstairs, or going downhill is also generally more painful than going uphill.   This is because going downstairs or going downhill places a greater demand on your quadriceps muscles than going uphill or upstairs.  Anterior knee pain is also aggravated by any activity, movement or exercise that places strain on your quadriceps muscle and knee cap.  Why is this?

Firstly, you need to understand the parts of the body involved when you get anterior knee pain (or patello-femoral syndrome).  If you look at the illustration below, you will see that the knee cap is positioned above the thighbone (femur) and that there is a muscle that is attached to the knee cap via a tendon, that is called the quadriceps muscle.  The quadriceps muscle is actually made up of 4 muscle bellies (recently a 5th muscle belly has been discovered).

"Knee Anatomy"Blausen.com staff. "Blausen gallery 2014". Wikiversity Journal of Medicine. DOI:10.15347/wjm/2014.010. ISSN 20018762. with written author permission for use.
“Knee Anatomy”Blausen.com staff. “Blausen gallery 2014”. Wikiversity Journal of Medicine. DOI:10.15347/wjm/2014.010. ISSN 20018762. with written author permission for use.

The action of your quadriceps muscle is to straighten the knee when the quadriceps muscle contracts.  Because the knee cap is attached to the quadriceps muscle, when you straighten and bend your knee, your knee cap moves up and down along the thigh bone in a groove.  This action is controlled by the quadriceps muscle.  In fact, your knee cap is there to shorten the lever of your quadriceps muscle and thus improve the contractile strength of your quadriceps muscle when it acts.  Thus they work together like hand and glove.

If you have weak quadriceps muscles, however, the knee cap is no longer well controlled in its movement up and down the groove in the thigh bone.  What happens is that when your quadriceps muscle contracts in this instance, your knee cap is pushed against the thigh bone and grinds the underside of your knee cap against your thigh bone, causing inflammation and your anterior knee pain/ patello-femoral syndrome.

What causes your quadriceps muscles to weaken and cause your knee cap to grind against your thigh bone creating anterior knee pain?  There are various scenarios.  A very common one occurs in children and teenagers, where a growth spurt has occurred and the bone is longer, but the quadriceps muscle and tendon haven’t caught up, causing a biomechanical imbalance resulting in anterior knee pain/patello-femoral syndrome.  Another scenario is when an injury to the knee has occurred that results in pain and swelling.  Any pain or swelling in the knee causes inhibition of your quadriceps muscle, which left untreated, can result in the development of secondary anterior knee pain/patello-femoral syndrome.  If you have had a knee injury, make certain that you have been to see your sports or OMT physiotherapist.  They are specially trained to help you resolve this problem quickly.

One of the factors that your sports or OMT physiotherapist will attend to is how to avoid anterior knee pain if you’ve had a growth spurt or knee injury or how to undo anterior knee pain caused by weak quadriceps muscles.

Since your weak quadriceps muscles are key to the problem of your anterior knee pain, knowing how to strengthen your quadriceps muscles in a pain free way, until the muscle is strong enough to pull your knee cap away from your thighbone while your knee bends and straightens during your activities, is pivotal in resolving the problem (read my post on strengthening your quadriceps muscles when you have anterior knee pain) and go see your sports or OMT physiotherapist for some treatment.