A Tale of Pelvic Asymmetry in Cycling
Heather Costas (MSPT, CIMT, Clinical Director Physical Therapy Team Rehabilitation),
Most of our skeletal systems are symmetrical, and correspondingly, so are many cycling components such as bike frames, handlebars, cranks and saddles. But every now and then, one of us has an asymmetry that doesn’t fit in this world of symmetry. Resolving that conflict involves figuring out the root cause: what and where the asymmetry is, and then applying an appropriate fix if one can be found.
Figuring out the root cause is important because different causes of asymmetry, such as scoliosis, leg length difference, and hip asymmetry, all have the same symptom: discomfort felt at the saddle. Rather than focusing solely on looking for the right saddle, the more appropriate way forward is to apply the right fix: in the case of a leg length difference, a shim at the shorter leg helps.
Unfortunately, many cyclists with asymmetry issues aren’t familiar with the overall process of determining the problems caused by asymmetry. To give an idea of the steps involved, we follow the progress of Ken Rylander, as he first gets his asymmetry diagnosed, then figures out the right kind of saddle needed.
Seven years ago, Ken was hit by a car while cycling and ruptured a disc (L5/S1). He had surgery to fix the debilitating nerve pain, but things continued to worsen. Five years later, all activity was getting painful, with cycling being the worst.
Ken was diagnosed with hypermobility syndrome — the ligaments in many places are too flexible and are not holding key joints tightly enough so that there is more movement than there should be (SI joint, shoulder, wrist). This makes the muscles work extra hard to do the job of the ligaments, creating excessive amounts of muscular tension.
As treatment for this condition, Ken worked with two doctors and a physical therapist. Ken gave feedback and described the symptoms to the doctors and Heather, his physical therapist. Working over many weeks, Heather was able to continually locate the primary causes of many of the pains and weaknesses that had formed over time in response to his asymmetry. These included a possible spinal rotation, as well as the possibility of a smaller right pelvic hemisphere (or smaller ischial tuberosity/sitbone). As a result, Ken can see and feel a noticeable twist in his upper body, especially when on the bike. It was even apparent during a video chat with his parents, where he could see that one of his shoulders was lower and further forward. This creates a great deal of excess muscular tension even at rest, as the muscles try to provide the
stability that the ligaments should be providing.
Ken’s physical therapist and doctor worked hard to address the structural issues with strengthening and osteo manipulations. His alignment improved along with his strength, however there was still a missing piece.
Riding with an Asymmetric Pelvis
When sitting on the saddle, Ken feels his left sit bone pushing onto the saddle, but the right one does not. In an attempt to find a better balance, Ken moves all around on the saddle as it is difficult to get both sit bones properly supported. It makes the saddle occasionally feel too high or too low as the pelvis rocks and over time the muscles fatigue. Cutouts and channels which should provide a pressure relief on the soft tissue don’t ever feel like they are doing their job. Saddles without channels or cutouts put even more pressure on the perineal area. In order to get both sit bones to “feel” the same amount of pressure on the saddle, Ken has to rotate his hips/sit bone to the right, and even this never feels quite right. By putting a straight edge across his hip bones, it is clear he is rotated toward the smaller sit bone with his hips not being at all perpendicular to the bike’s top tube.
Finding a General Solution
Ken was first evaluated by both his doctor and physical therapist for leg length difference, sacral and lumbar rotations, which were found to be negligible, and were corrected during PT without him sitting on a bike seat. They then looked into lifting the right sitbone using an ischial lift: this is a rectangular, silicon-like slab that doesn’t compress too much. An ischial lift around 5mm thick placed on the saddle improves Ken’s alignment with equal pressure through his ischial tuberosities and decreases pelvic and lumbar rotation.
Both sit bones now feel like they are similarly supported, and the twisting of the hips goes away to a very large extent. With equal support, pedaling is much more even on both sides and the saddle cutouts and channels provide a great deal of relief to the soft tissue. The saddle now feels like it is the proper width and ironically with more support under the sitbones, the saddle also feels less obvious under him. To a large extent most saddle related discomfort goes completely away.
Finding An Appropriate Saddle Solution
Ken, his doctor and physical therapist are now convinced that a saddle, with the right side 5mm higher than the left, is the correct solution. After coming across Meld Solutions’ website, Ken contacted Meld and opened a discussion about ways they could help with his problem. Considerations for a solution included a) the impact of natural bias, b) ways of implementing saddle asymmetry, c) testing methodology and resources required, and d) the requirement that implementation should not require special skills, tools or materials.
A. Natural Bias
All anatomical imprints captured by Meld have displayed asymmetry to various degrees. The issue is usually not with the skeletal structure, but with natural bias: depending on how we regularly use our muscles, we will subconsciously lean to one side. This means the imprint itself cannot be directly used to correct for structural asymmetry, and that other inputs are necessary. For instance, X-rays/MRIs may be helpful, but are typically not cost-effective, nor do they always clearly show small deviations in anatomical structure according to Ken’s doctor. Therefore, we need to look for an alternate solution.
B. Saddle Asymmetry Implementation
There are two general ways of implementing saddle asymmetry: via the shell, or the padding. Shell asymmetry usually requires altering of its design, and depending on the implementation, can result in a difference in flexibility between the two sides. Padding asymmetry is implemented by adding thicker/more layers of padding to one side. The former is more resource intensive than the latter, and may result in other side effects due to flexibility differences.
C. Testing Methodology & Required Resources
Each case of asymmetry is usually unique and hence a solution for one may not work for another, or incur unforeseen side effect(s). This in turn means we should expect some degree of trial-and-error.
To avoid high costs, we need to make each trial inexpensive. Padding asymmetry is therefore highly preferable to shell asymmetry: we can begin by temporarily sticking multiple layers of padding (possibly of different thicknesses) onto an existing saddle, and taking short rides. By changing the number of layers or padding thickness, we can hopefully arrive at an acceptable padding thickness between the two sides.
D. Skills and Required Resources
Finally, to make the solution available to as many people as possible, we look for one that requires fewer skills to implement. Asymmetry achieved via different padding thicknesses requires significantly less skill and resources than shell asymmetry: different pieces of padding, some adhesive, and a bit of skill to re-cover an existing saddle.
With the above considerations in mind, we decided on the following way forward:
- Meld ships Ken a few pieces of padding, of various thicknesses
- Ken temporarily sticks different combinations of padding onto his existing saddle, takes a few test rides, and determines an acceptable difference in height between the two sides of his saddle
- Meld designs a symmetrical saddle shell based on Ken’s anatomy, but increases padding thickness on one side accordingly
Trial-and-Error Using Temporary Padding
Ken worked with his physical therapist using the various pieces of padding. They started with a baseline measurement of the angle of Ken’s spine/head from the vertical, as well as measurements from his right and left acromion (shoulder blade) down to the surface. These measurements were subsequently compared with those taken using different combinations of padding. Due to the slightly compressive nature of the saddle padding, additional padding was needed, and a thickness of 7mm was determined to work well.
Ken’s physical therapist then observed him riding with and without the additional padding. While the padding compressed some, most of the problem was observed to be corrected. Hence, they finalized their decision with the addition of 7mm of padding to the right side of the saddle.
Saddle Design and Construction
With the required difference in padding thickness, Ken proceeded with Meld’s anatomy-customized saddle making process:
- Capturing of his anatomy’s imprint using an impression foam. The rear view of the imprint’s cross section shows almost no difference in depth between the sitbones, likely due to natural bias
- Scanning of the foam to digitize the imprint
- Generation of the shell model from the digital imprint
- Manufacturing of the saddle
The only difference between a symmetrical, mass-customized saddle and Ken’s is the addition of more padding on one side. The final saddle is shown in the photos below:
Short Term, Long Term Experiences
(Ken’s account of what has transpired since he received the saddle from Meld)
After going through the process of applying different thicknesses of padding to the saddle over the period of a month, my expectation was that it was helpful in providing a much more symmetrical support to my sit bones. There was much less need to shift/rotate my hips about all over the saddle to try to find a comfortable spot. To a large degree it was also helpful in providing some relief to the perineal pressure I have always felt while riding.
When the new Meld saddle arrived, I’m not sure I was prepared for the degree of improvement it provided. Where the additional padding that we used during the prototyping period was helpful, the completed saddle was completely transformative. My first ride with the new saddle was longer, harder and less fatiguing than I have experienced in a long time. It’s funny that when you have a problem that you are not aware of, and suddenly you find a solution for it, it changes everything you used to believe. I always believed that the muscular fatigue I felt was normal — I always marveled at people who could ride hard over multiple days. For my body the subtle rocking of the pelvis during pedaling built up muscular tension and fatigue over time that no amount of stretching or light activity would ameliorate. The support offered by the saddle far eclipsed what I had experienced with the prototype padding. It’s fit was so comfortable and so supportive that in a way it almost felt like no saddle at all. I have been through at least a dozen saddles over many years. The Meld saddle was like having just the right amount of support under my sit bones, but everything else just got out of the way. It was a thrilling and strange experience all at the same time. I’m not sure I’ve ever felt such support and comfort from a saddle (due to the asymmetry of my pelvis/sit bones).
Pretty much instantly, my posture on the bike changed. Where I have always been “twisted” or leaning on my arms/hands too much, with the Meld saddle the twisting and subconscious adjusting I had always done with my hips was nearly gone. With support under my pelvis, I no longer put as much weight on my arms/hands/handlebars. The pedal stroke is now very different — with proper support I feel quite a bit stronger. With no change in fitness, or other equipment, my ride times have nearly doubled, and I can ride much more consistently than I was even just a few months ago. This has required a bit of a paradigm change as well.
When your body gets used to trying to make adjustments, it takes a little bit of time to break old habits. The neat thing about having my problem addressed so well with the additional padding on the Meld saddle is that, in a way, it almost feels self correcting. I can feel when I’m not quite in the right position and adjustments are easier to do, something I just couldn’t do before. I spent a fair amount of time having my family take pictures and videos of me riding because many times what felt right to me didn’t look at all right to them. And what looked right, rarely felt right to me. It was a difficult problem to overcome.
I’m not sure someone who doesn’t have saddle related problems can really understand how transformative this is. I’ve ridden for nearly 30 years and saddles have always been a problem for me. When I was younger, this wasn’t nearly as much of a problem, but with age, injuries and finally an accident the problems just kept getting worse. I started thinking that my sit bones were really far apart, or I needed to rotate my pelvis forward, or that there wasn’t enough padding, or too much padding. Nothing ever really helped much — different but not better. Unfortunately it took something catastrophic to find the problem and a solution, but the effect of the saddle in correcting this problem has been unparalleled.
Long term I have no doubts that the saddle should allow me to finally resume riding on a much more consistent basis. Even after my first three rides the Meld saddle feels like it been on my bike for years. It is so comfortable, it feels like nothing else I have ever ridden. The comfort of the saddle (even if I just consider my “normal” sitbone) is fantastic.
I’m sure like most riders, I’ve spent far more on bikes than my ability demands, but this relatively small investment in a custom saddle has been worth it many times over. With Meld’s offer to recover/re-pad the saddle should the need arise, I will be able to make any adjustments
if things change over time.
Found this article useful? Check out other cycling-related stuff at meld3d.com/blog.