Do you suffer lower back pain when on the bike? Well you are not alone. A Norwegian study in 2010 followed 109 elite cyclists and found that over the course of a year, 58% of them had performance limiting lower back pain. A mate of mine always helpfully reminds me to 'keep the rubber bits down' when I ride thus avoiding those pesky traumatic injuries that happens when you forget to do so. The back pain I'm talking about though is not from having a stack but from overuse.
Bike related lower back pain can be caused by a number of factors including your position on the bike, leg length differences, strength or mobility deficits and sometimes it can be caused by what sounds a little bit fancy, viscoelastic creep of the passive support structures.
Let’s go through them one by one.
Bike set up can play a big part in lower back pain. The most obvious place to start looking is the saddle height. A saddle that is too high will cause over reaching at the bottom of the pedal stroke. This leads to rocking of the pelvis from side to side and can definitely contribute to pain in the lower back. Have your saddle at a height where you can maintain constant connection with your sit bones and stop the rockin'n'rollin
On the flip side - a saddle that is too low will cause you to ride in exaggerated hip and knee flexed position. Have you ever seen someone who looks like they riding their kids bike? A saddle too low can contribute to lower back pain by causing overactivity of the psoas muscle. Psoas is a muscle that flexes the hip and attaches to your lumbar spine - if it gets tight it will pull your spine forward and potentially cause pain.
To ride a bike, which is a symmetrical piece of equipment, ideally riders would also be symmetrical. Unfortunately this is seldom the case. Most people have one leg longer than the other. And while you can get away with up to a 10mm leg length difference when walking, on a bike even a small 2-3mm difference can create asymmetry and pelvic tilting downwards at the bottom of the pedals stroke on the short limb side. Trying to measure the legs with a tape measure is inherently flawed - if a leg length difference is a suspected then measuring the legs on a CT scan can reveal, down to the millimetre, what the discrepancy is. A shim under the short leg cleat will improve symmetry and reduce pelvic tilting.
This is a CT scan of a woman with back pain when riding whose left femur or thigh bone was 14.1mm longer than her right femur. No wonder they were having trouble!!
Another study in 2012 looked at cyclists who experienced lower back pain and compared them to those who rode pain free. The main difference between the bike set ups of the two groups was that those who had lower back pain had their saddle tilted nose up by, on average, 3 degrees. If the nose of your saddle is tipped upwards you tend to ride with what’s known as a “posterior pelvic tilt” which in turn leads to increase lumbar flexion. Picture a Slumpy McGlumpy sitting with a curved lumbar spine on their saddle.
The other reason people ride in a posterior pelvic tilt is because of saddle soreness. If you are having trouble with pain or numbness of your "bits" on the saddle the tendency is to try and offload them by tilting your pelvic back. But as soon as you do that your lumbar spine shifts into flexion and strains the supportive structure of lower back.
Tight hamstrings can also lead to posterior pelvic tilting, lumbar flexion and potential lower back pain.
Riding in lumbar flexion can lead to viscoelastic creep of the intervertebral discs.
So what is viscoelastic creep?
Imagine I had a rubber band, I stretched it out and then let it go immediately. Snap. The rubber band returns to its original length. But if I got the same rubber band and stretched it under high load for 2 hours - what would happen then? When I let it go it would remain elongated, out of shape and not very useful. That is viscoelastic creep and what is potentially happening to our vertebral discs and ligaments when we spend more than 2 hours on our bike in lumbar flexion.
Have you ever, or maybe you've seen one of your friends, get off the bike after a longer ride and then have trouble standing upright? The rider flexes over with their back bent forwards for a while, hands on knees until eventually the stiffness subsides and they can stand tall again. This can be caused by 'flexion intolerance’. Studies have shown that being in sustained lumbar flexion (think riding a bike for 2hrs with a curved lower back, posterior pelvic tilt) can cause viscoelastic creep of the vertebral discs.
So what to do? Avoid getting into a flexed lumbar spine position by being super strong through the core and getting your saddle position and comfort sorted. Also spend time in and out of the saddle and don't be stuck like glue in one position for too long.
Sitting has been recently labelled the new smoking in terms of its negative effects on our health. The problem with excessive sitting, in the car, at work in front of a computer, at home in front of the tele, or even on our bike, is that we are spending all our time in a hip flexed position. What happens then is we can lose our ability to extend the hip by losing connection with our biggest muscle of the body, our Gluteus Maximus. This leads to quad dominance on the bike, stomping when pedalling with poor gluteal activation and resultant poor stability on the saddle. If you are having isolated cramping in your quads or calves it could be you’re not using your glutes efficiently! Plus the glutes can contribute up to 50 % of the power to the pedal. So if your glutes are not firing properly not only could you be getting back pain but you are not riding as fast or as strong as you could be. We've got to stand more often when not riding, strengthen our lazy butts and get more power to the pedals.
As you can see there are a lot of potential causes for lower back pain on the bike - so what are the best bets to avoid this painful condition?
Get your glutes so strong that you can crack walnuts with them, improve your hip, psoas and hamstring mobility, get your saddle height and position dialled in and if you think you might have one short leg get it measured properly.