This is a very common question I hear around the triathlon world. Generally this is associated with Ironman or 70.3 events however I do hear some Olympic distance athletes report this sensation as well.
What can cause the numbness?
There are many factors that can cause numbness in the foot when cycling. To start with we need to know where the numbness is. Different things can cause numbness in different parts of the foot.
Generally numbness means that messages from a nerve a being blocked. This can be compression of a nerve or the compression of the blood supply to the nerve.
There are many things that can cause numbness in you feet when cycling including:
- Poor bike fit
- Poor cleat position
- Shoes too narrow/ tight/ small causing compression of the interdigital nerves (nerves that run between the long bones in your feet)
- Referral from lower back/ sciatic nerve (L5-S1)
- Poor Pedaling technique à Pushing too much during your pedal stroke
- Poor ache support (if you need this)
If we look at specific areas of numbness and what can be causing that numbness:
Numbness under the ball of your foot can be caused by
- Poor cleat position – usually cleat too far forward
- Referral from Lumbar spine (L5)
- Cycling shoes too tight/ narrow/ small causing compression of a interdigital nerve (nerve between some of the long bones of your feet)
- Poor bike set up (seat too high)
- Poor arch support (if you need this)
- Poor pedaling technique
Numbness along the outside of your foot –
- Referral from Lumbar Spine (S1)
- Poor cleat position (Rotated in or out)
- Poor pedaling technique
Numbness under the base of your toes (across your whole foot)
- Cycling shoes too tight/ narrow/ small causing compression of a interdigital nerve (nerve between some of the long bones of your feet)
- Poor cleat position – usually cleat too far forward
- Poor arch support (if you need this)
- Poor pedaling technique
This list of causes unfortunately doesn’t cover every possible cause but does cover the most common.
What should I do to fix the problem?
As you can see there can be many causes of this problem. If you are suffering with this I would start by getting a proper bike fit done. This is vitally important for the longevity of your cycling/triathlon career. It will not only make you a more efficient cyclist but will prevent future injuries. This should include adjustment of your cleat position. During your bike fit session I would also have a chat about your cycling technique. Get the bike fitter to assess your cycling technique and give you some pointers about how to correctly cycle. There are plenty of drills around as well that they should be able to run through with you.
Whilst you’re at it I would also have a look at your cycling shoes. How do they fit? Are they too small/ narrow or tight? Is there any area of your foot that is being squashed too much? Does the tongue of the shoe dig into your foot. All of these things can cause numbness in your foot. If any of these things are occurring get down to your local bike shop and invest in some new proper fitting shoes. Make sure the bike shop fit the shoes to you feet.
If after all of this you are still experiencing the numbness in your feet you should seek the assistance of a professional. A physio with knowledge of cycling is a good place to start. They will be able to assess your lower back/ pelvis and surrounding muscles to see if there is anything here that can be causing your problem.
They will also be able to assess the biomechanics of your feet to see if soft cycling orthotics may be appropriate. If this is the case then you are best off being referred to a Sports Podiatrist who again has experience with cyclists. They will be able to make you a pair that will be unique to your feet.
Hopefully after you go through this process you will have solved your numb foot issue and cycling can become enjoyable again.