Have a pain in the a** while sitting on your bike saddle? Optimize your saddle using pressure mapping!

In Pelvic Pain by Morgan Conner2 Comments

Guest post by Justin Lucke and Morgan Conner

In bike fit, oftentimes small changes can lead to profound improvements, but in practice it can be hard to quantify the impact. In this blog post Morgan talked about her quest to find a better seat and how using trial and error found something that worked a lot better. And it is true that trying out multiple seats is super helpful in solving the saddle pressure dilemma. A poorly fitted saddle or bike fit can contribute to or exacerbate already existing pelvic floor pain. 

In fact, one cause of pelvic floor pain, pudendal neuralgia, was long considered to be a problem that only happened to male cyclists! The pudendal nerve arises from sacrum, taveling through alcocks canal with the pudendal artery and vein to innervate the pelvic floor. It is the only nerve in the body that has both sensory and motor functions as well as autonomic functions. This means that it is involved in controlling the contraction and relaxation of pelvic floor muscles (motor function), transmitting sensation information (such as pain, pressure, or touch) to the brain (sensory function) and regulating urinary, bowel and sexual function (autonomic function). Getting back to anatomy, the pudendal nerve has a tortuous course through the pelvic floor and can be compressed when cycling leading to pain, numbness or tingling in the genitals or pelvic floor muscle dysfunction. The good news is that it does not have to! We teamed up with Curtis Cramblett and Justin Lucke at Revolutions in Fitness to talk about one way to help improve your bike saddle fit and comfort. 

But in addition to trying new saddles, Revolutions in Fitness uses pressure mapping to measure an extra dimension that helps isolate cause and effect from small changes. While the broad approach might be to start switching saddles and look for subjective feedback on the saddle to improve, along with objective markers like visual stability, pressure mapping provides a more focused assessment to help choose the right saddle and then optimize the position. 

In this case, pressure mapping showed that the saddle was broadly appropriate (no pressure in the center on nerves and blood vessels; pressure on the outside focused on bony structures). Even so, at the start, saddle pressure was still pretty awful, with pressure creeping over 1000 milibars there was room for improvement:

The current setup was based around a 100mm long stem (attaches the handlebar to the bike) with +17 degrees of offset (offset is the angle of the stem relative to the bike’s steering, where positive means the stem is pointing up while negative is pointing down). Typically, a rider would use a stem with more positive offset to help raise the bars and take pressure off of the neck and back and help open up the hips. The flip side of higher bars, however, can be a reduction handling and stability and less ability to powerfully recruit the glutes. In this case, the rider had improved mobility, so strain on the neck, back and hips was less of an issue, and wanted to improve handling and performance. So we were lowering the bars to help achieve this goal.  

Using an adjustable fit stem, we were able to move between several different setups and benchmark using pressure mapping. Starting with a switch to a +8 degree offset, pressure was better — more stable (shown by the red line being shorter, flatter and more centered), lower and better balanced left to right:

But the benefits of using pressure mapping start to really appear when we overshot the likely best option.  Moving from a +8 offset to a zero offset saw pressure go back up:

Clearly something is going on here that subjective experience — how does that feel? — might not capture.  Making the next step, from zero offset to -8 offset really shows the trend:

Pressure goes up once again so going lower is not the right path in this case. Re-setting the stem to +8 offset validates the original observation that a little lower, and a little longer, has a big impact and is the right move at this point for the rider:

The takeaway is that pressure mapping allows us to benchmark the starting point, document the changes and establish one way to define improvement. In this case, pressure mapping allowed us to move towards the rider’s goal — performance improvement — while increasing comfort.

You might find that the right bike saddle fit clears up your symptoms while riding but if not you may want to consider seeing a pelvic floor physical therapist to see if there are any muscular or connective tissue contributions that may need to be addressed. If you are wondering what a pelvic floor physical therapy evaluation is like check out this blog post.

To schedule a bike fitting with Curtis or Justin you can find information at the Revolutions in Fitness website: Revolutionsinfitness.com, email bikefit@revolutionsinfirness.com or call their office at (650) 260-4743. 

To schedule an in person appointment for a pelvic floor physical therapy evaluation with a physical therapist at PHRC you can contact us here or if you are interested in a digital health appointment you can schedule one here.

Comments

  1. Excellent post on this subject! I’ve been plagued with this problem for several years and this helps make sense of it all. Great research!

    1. So glad we can help make sense of it all and provide you with some clarity!

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