P HI L BURT

When should you make corrections, and when should you leave well alone?

Burt spent 12 years as head of physio at British Cycling and five years as consultant physio at Team Ineos. philburtinnovation.co.uk

“Let’s get one thing clear straight away: we are all asymmetrical, to some degree, somewhere”

Ilove my job so much, and one of the main reasons why is the infinite number of variations you find between a rider and their bike. The rider is adaptable, the bike adjustable, so the trick is finding out which one of these is the problem and which needs changing.

One of the most common issues people have interacting with a solid, fixed bike is coping with their asymmetry, so let’s get one thing clear straight away: we are all asymmetrical, to some degree, somewhere. Human beings are not completely symmetrical and nor should they be. Bikes, however, generally are – and this can be an issue for some people. Bikes can make excellent asymmetryfinding machines, in fact.

Take leg length for example. We’ve touched on this before but actual leg length differences (where one of your leg bones is longer or shorter than the other) are not that common and, it turns out, are very hard to detect. Functional leg length differences, however, are very common. This is where one leg appears to be longer or shorter due to the twist in our pelvis, the tightness of one hip compared to the other or the slight bend in your spine.

We cope with these differences easily in daily activities, such as walking, for example. The body has so many different points at which it can iron out, say, a longer leg by simply collapsing the arch of the foot, which can decrease the overall height of the leg.

In cycling these adjustments become a whole lot harder. Seated on the bike you are fixed into a position that doesn’t change – the distance to the pedals is the same on both sides and the chances to manipulate the body internally are therefore far fewer.

Ipsilateral, or one-sided, knee pain or saddle sores can often be due to a functional leg length difference. In the first instance of knee pain it is nearly always the longer leg as the saddle height is optimised for the shorter leg leaving the longer leg to cope with an effectively too low position and too much knee flexion. Conversely, some people will sit off to one side to help the shorter leg reach the pedal resulting in increased pressure and saddle soreness.

However, it may surprise you that I don’t believe in everybody being perfectly adjusted to the last millimetre of symmetry on a bike. For sure, if you’re having issues, such as the ones mentioned above, then making some adjustments to help accommodate asymmetry is valuable.

But if you’re not having any issues, I would leave asymmetry well alone. Who cares if one knee kicks out slightly now and then, or that your legs aren’t going straight up and down on both sides? Those who seek symmetry in humans are often disappointed or frustrated at the lack of success. I like to refer to the concept of ‘preferred movement pathway’. We are all different, with varying strengths and weaknesses, injuries and biomechanics. How we pedal is our ‘preferred’ way of doing so considering all those points. Trying to change that can open up a can of worms and lead to bigger issues.

The classic belief I can, hopefully, dismiss is to do with asymmetry in relation to power production. The advent of more and more power meters, and therefore measurements, has made us all the more aware of what was always there: a left/right difference. But for the record, the learned biomechanicists that I know and trust wouldn’t bat an eye lid at a difference of less than 10 per cent. That sounds huge, doesn’t it? But if you accept that we are all basically wonky to some degree, why would we expect each leg’s power production to be near equal.

The old adage of, ‘If it ain’t broke…’ really does apply in this particular case.