Lower back pain on the bike
Lower back pain on the bike usually comes from a pelvis that rocks too much on every stroke, most often because the saddle is too high. The other common cause is limited hip mobility that the lumbar spine ends up compensating for. It is fixed by adjusting saddle height and angle and by matching the position to the mobility you actually have. Core work helps, but only once the position is right.
- How common
- Top threeBehind knee and neck
- Usually solved in
- 1 sessionSaddle height almost always comes down
- What we measure
- Hip mobilityMeasured before anything is adjusted
- Service
- €180Full bike fit
The area on the diagram
Which part of the fit this complaint belongs to
Every point links to its own complaint
Where it is decided
- Usual cause
- Saddle too high, or hips that will not flex enough.
- What we adjust
- Saddle height and angle, setback, bar height.
- Related measurements
- saddle heightstacktorso angle
The problem is the pelvis, not the back
When the saddle is too high, your leg cannot reach bottom dead centre comfortably and the pelvis rocks from side to side to get there. That rocking, repeated thousands of times in a ride, is absorbed by your lower back.
The other cause is the opposite one. If your hip does not flex enough for the position you have chosen, the lumbar spine rounds to make up the difference and then works in sustained flexion for hours at a time.
Both roads end in the same place: a lower back doing work the hips and the legs should be doing. Which of the two it is changes the fix completely, which is why the measuring comes before the spanners.
Measuring your mobility changes the fit
Two riders of the same height can need very different positions if one flexes at the hip twenty degrees more than the other. This is exactly what separates a bike fit from a sizing chart.
In the anatomical assessment we measure hip flexion, lumbar extension, hamstring length and any leg length difference. The result governs everything that follows: there is no point putting you in a position your body cannot hold.
- Saddle height, almost always downwards, verified with the knee angle in 3D rather than the heel rule.
- Saddle angle, so the pelvis sits on the sit bones instead of rolling forward off them.
- Setback, which changes where your weight falls and how hard the back has to work to hold it.
- Bar height, so that total torso flexion stays inside what your hip can actually give.
Saddle height is the change riders resist most, because coming down feels like a loss. It is not. A leg that reaches bottom dead centre without the pelvis chasing after it puts its power down in a cleaner line, and the back stops paying the difference.
When it is not the bike
If you also have the pain sitting on the sofa or getting out of bed, the bike is only bringing it to the surface. A fit helps keep it from getting worse, but the cause has to be treated by a healthcare professional. If there is pain radiating into the leg, tingling or loss of strength, get that seen to before anything else.
We will also say plainly when the fit is only part of the answer. A position that suits the mobility you have today can be opened up again once that mobility improves, and that is worth a follow-up rather than a new bike.
Questions about this complaint
Is a more upright position better for my back?
Does a saddle with a cut-out help?
I do core work and it still hurts. Why?
I have to stand up and stretch every ten minutes. Is that normal?
Does this sound like your case?
Tell us when the pain shows up and on what kind of ride. We will tell you whether a fit solves it before you book anything.