Twisted: Tackling pelvic asymmetry in bike fitting
Humans are designed asymmetrically. Specifically, more than 90% of both males and females present with a forward rotated right side of their pelvis and a backward rotation of their left pelvis.
The (possible) causes
Many theories have been posed.
One theory suggests that the twist starts in the human embryonic stage of development when the placement of our vital organs commences. The heart, stomach, spleen and pancreas all lay towards the left. The gall bladder and liver are on your right. Our left lung has 2 lobes or sections, whilst the right lung has three. The idea of making room for more organs on one side could lead to the pelvis rotation that clinicians, bike fitters, medical professionals and others have noticed for centuries.
Another theory is cerebella dominance – a fancy phrase used to describe how the two different sides of the brain function differently. Similar to having a dominant upper limb (often the right arm and hand) we also have a dominant lower limb. Many riders will will be right leg dominant and hence pull the pelvis forwards and downwards as they pedal.
For others, a twist might be due to a leg length difference. Here I’m talking about a true anatomical difference that is caused by an asymmetry in the bones of the left and right legs. This can only be measured accurately by radiological examination ie Xrays. On the shorter leg side, often – but not always – I will observe a lower pelvis when seated on the bike as the limb “reaches” more for the pedal.
Yet another cause can be a functional difference between the legs. This typically occurs simply from living life. In fact if you’ve ever sat in a café and people-watched for long enough, you’ll see causes everywhere: crossing the same leg over the other frequently throughout the day (women are notorious for this one); hanging off one hip whilst having a drink at the pub; or carrying your mobile phone to one ear whilst simultaneously washing the dishes and carrying your child on the other hip (I’m quite skilled at this one!).
Our inherent twists within the body, combined with our habits formed over many years, means that almost everyone sits skewed on the bike!
For some, the combination of an asymmetrical human with a symmetrical piece of equipment that ‘fixes’ the hands and shoulders, the pelvis and the feet can lead to problems. These include
- lower back pain,
- lateral knee pain,
- saddle pressure and pain, often on one side more than the other,
- shoulder or neck pain, again often on one side.
For these riders, reducing or otherwise accommodating their twist is crucial to comfortable and injury free cycling.
The majority of ‘twisted’ cyclists don’t actually experience discomfort. The human body has been designed amazingly and can often adapt to its own idiosyncrasies. Whilst skewed in standing or walking, a rider might hop on the bike and look quite symmetrical or not report any discomfort or pain.
So if this is you then you have nothing to worry about, right? The answer is a definite maybe. As a bike fitter, preventing and treating injuries or pain is only part of what I do. I fit for comfort, injury avoidance and… performance.
A twist, if it’s big enough, can affect the total amount of power that can be generated as well as the power balance between legs. But there is another aspect of performance that’s all too often overlooked: bike handling.
A question I like to pose riders is “Can you ride your bike no hands ?
My husband Dave is one twisted guy. He has the classic right pelvis drop and counter clockwise rotation. It can be seen quite clearly when riding behind him. The seam of his knicks deviates to the left and compensatory kinks continue up through his spine, resulting in a dropped left shoulder. Whilst he rides with minimal discomfort most of the time, ask him to ride “no hands” and the bike wants to veer to the left, deviating horribly towards the gutter. It’s the real tell tale sign that he needs some hands on soft tissue therapy to address his tighter right hip flexors and hamstrings. Post treatment riding no hands becomes much, much easier.
It’s not just riding no hands that is affected. Cornering, tracking and bunch riding can all be adversely impacted through the off centring of a rider’s weight and subsequent counter steer.
What about you? Can you ride no-handed in a straight line? Do you struggle to get round corners and can’t work out why? Do your cleats inexplicably wear out more on one side than the other? Are your knicks roughed up more on one inner thigh?
These are all telltale signs that you might not be sitting symmetrically and that a bike fit is in order.
The possible solution(s)
A pelvic twist can be tackled in a number of ways.
For a bike fitter, the obvious approach is to adjust the bike to accommodate the twist. There are a number of solutions which, used individually or in combination, can reduce its impact. These include
- adjusting saddle height to accommodate the functional leg length differences
- trying different saddles, looking for one that better supports the pelvis and
- adjusting the length of one or both pedal spindles.
For a Soft Tissue Therapist, Physio etc. the obvious approach is to address the body and reduce the twist itself. Treatments might include
- trigger point therapy and
- myofascial tissue tension.
For an exercise physiologist the obvious approach is to address the body’s function by prescribing a program of mobility, stability and strengthening exercises.
The Winning Position solution
A bike fit at Winning Position is a marriage between the body and the bike. Because I am a Bike Fitter, a Soft Tissue Therapist and an Exercise Physiologist I can, and do, draw from all three fields when addressing fit issues. There is no single solution that I apply in every case. Rather I take your cycling goals and aspirations into account when formulating my approach.
Are you aiming for the top of the sport? Then power production and longevity under high and sustained loads are your goals. You are motivated to put in the investment in time and effort required to address the underlying cause (the twist). Your solution will likely include more soft tissue therapy and exercise programs than average so that you can get the most out of your body. The bike will be adjusted to accommodate your twist but with an eye to reducing or removing the adjustments as your body responds to treatment.
Do you lead a busy life with work and family commitments, commute by bike and like to squeeze a ride in on the weekends? If so then it can be difficult (and perhaps unneccessary) to find the time to iron out all the kinks. Often the best approach will be to treat you body enough to ensure that you will be injury free and then adjust the bike to your body as much as possible.
In any case, I’m sure that together we can find your winning position.