Lower back pain

Any suggestions on lower back pain, only while putting in hard efforts on the mountain bike. It’s fine if I’m soft pedaling but the second I start really putting in 100% effort it’s very painful. Doesn’t matter if sitting or standing. I have gotten a bike fit and it made no change. So wondering if there are any good exercises or stretches I can be doing. I have visited a chiropractor and I do the standard weight lifting routines (deadlifts + squats etc) and planks. I don’t do much for stretching right now besides a little bit here and there for hip flexors.

Thank you.

Is this sciatic pain or general soreness?

I’m not sure exactly what sciatic pain is, but it’s very sharp knife like pain right in the middle of my lower back. It can start hurting as soon as 5-10 mins into my ride if I’m pushing hard.

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How confident are you in the fit? Specifically saddle height and general reach?

It all feels pretty good as long as I’m not pushing 100% effort. I can ride at 60-80% effort for. 2+ hour ride no problem. So I’m not sure, but it seems to feel good.

I notice the same issue this week during Clark. I made a small comment in the Today’s workout thread. What workout did you do today? (2018/2019) - #5766 by AnotherCyclist

As you, I am riding a MTB too. My first thought is a weak core and I will start to get rid of it starting from 1st of December with exercising.

I get this too and so far my humbling conclusion is that recruiting the wrong muscles to cycle will cause pain. This lead me to conclude I wasn’t as strong as I thought I was on the bike. A bit like an untrained deadlifter being able to lift a heavier weight at the expense of form. So have been focusing a lot on isolating quad/ham movements and using core for stability. These were just my personal concussions - I think this issues vary from person to person.


I’ve had historic problems with this and lately was having the pain constantly. Physiotherapist diagnosed it as being a weak core from having a job that has me sitting all day combined with working out by… sitting down on a bike.

Something you might want to think about if you sit a lot for your job as well.

Pain free since 2012. Prior to that I suffered on and off over the years finally resulting in a 2 disc injury in late 2010. I spent most of 2011 working with a PT. What he said about me and I presume most cyclist:

  1. Too much lumbar spine flexion or far from neutral spin on the bike.
  2. A lot of rotation of the spine while pedaling. More power=more rotation.
  3. In general I had muscles that were inactive or dormant for lack of a better term.

To fix 2 and 3 we had to get through the acute disc injury. When appropriate we started on a comprehensive muscle activation and core stabilization routine. I could write a book and it is way too involved to discuss here but, one of the key exercises for me was a lumbar extension machine called Med-X. Basically, it isolated muscles that extend and stabilize the spine. Along with this we did so many strange stabilization type exercises with balls, on soft pads, one footed etc…exercises I thought “this is bullshit” but, what was happening was the PT was basically trying to get certain muscles to start firing again. When they did we worked strength.

Once back on the bike to fix 1 I did a fit but, more than a fit I had to learn to sit on the bike properly. Not saying you don’t but, most do not.

I still do a bit of the routine my PT prescribed as maintenance. God forbid I ever go back to that pan. Best!


I see mountain biking as quite dynamic, also for my core. I have issues with my lower back since the age of 16.
Core exercises help, but I also get good results from training my legs. When some muscles in your legs are weaker your back muscles take over or try to help. For me cycling has helped a lot, because I have the feeling I can balance the amount of stress on the muscles better. When I do core exercises or squats I have the tendency to overreach resulting in back pain and soreness.

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RE the fit:

It is possible more load is leading to heel drop. As you push bigger forces your body recruits different muscles and assumes a different position. This can lead to pelvic rock and general pain from back muscle engagement should there be an impingement, weakness or issue with position.

It can be exacerbated if cranks are too long for you or the fit (longer cranks can allow less reach/tilt due to closing hip angle at top), especially if a fit is transferred from say a road bike to MTB (road may have shorter cranks).

Another possibility, leading on from the positional thing, is the reach or angles are not right. It is typical for the torso to shorten under higher loads, this can additionally change pelvic tilt. Reach, your back angle, bar height and bar shape can impact this.

Personally I would do a chunk of core work if is totally pain free, but would also revisit the fit (ideally in the same state where you have an issue - i.e. if pain worse when tired ride to the fitter and put the miles in first).

All fitters are not the same and it is so disappointing when people say ‘get a fit’ without qualifying it. I have had two poor and inappropriate fits over the years. Both were Retul qualified (i.e. paid to go on a 3 day course, if you are feeling cynical), one with a sports science backgrounds and Retul Level 2 (TT/aero). Both got saddle height spot on but no other aspect of the fit worked for longer rides.
Third fit changed almost nothing on saddle position but big changes on front end and loads more comfort. She has a physio background, rode herself and now works for one of the most prestigious fitters in the UK - not a surprise to me but is a shame she is no longer local!

I would also politely suggest a physio rather than a chiropractor. An osteopath has worked wonders with me in the past but my personal opinion is neither is a replacement for a physio, especially one who rides or has fitted people on bikes themselves.

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A sharp pain that comes on suddenly would be a warning sign for me, and I would see a physio. Typically, weak core pain would be more something that comes on later in longer rides, once the core muscles tire.

I agree with that. If it was a general soreness all around the lower back area, I’d say you need to find a good P.T and make sure you hinge correctly. This is something similar to what you’d do during dead lifts or rows.

For real sharp pain, please go and see the doctor to make sure it is nothing serious.

Unfortunately a doctor or physio is not in the financial cards but thank you for the suggestions.

I can deadlift 400+ and squat 300+ with no pain, I would assume that would mean things can’t be too bad?

Any pain is a sign something isn’t right, you say you have pain when riding.

I would assume you do both those moves with good form, perhaps that isn’t the case on the bike?

I can squat and lift (a lot less) without pain but equally I can rattle out a burst of 1000+ watts on a bike pain free too.

Putting all this together, I’m guessing the pain is disc pain. And likely from asymmetrical loading while riding, since you say you can squat fine.

A good PT should be able to diagnose (although possible they’ll recommend an MRI needed), and disc pain can often (though not always) be resolved with PT.

You can also try your own core strengthening program. Include single leg strength exercises in place of squat sets. When you do the single leg stuff, focus on tensing your core to try prevent your pelvis from tilting.

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Thanks for the reply. I do everything in the gym with both hands and legs at once, so that could make sense. I will try to start working more single sided stuff and see if that helps!

I’ve ALWAYS had a weak core and glutes (my low back has always gone dull/achy 40ish mins into hard rides) but this sharp pain early into a ride is new this season.

I’m definitely going to put this into action along with more core and glute work.

Would you guys say it’s okay to keep doing base work with zero pain on the spin bike while I work on the issue?

Planks, plank rows, side planks, side plank rows are all good core exercises.

For single leg, start with backward lunges, holding a dumbbell on the same side as the leg doing the work. That’s a good exercise to start with as it doesn’t put as much torsion on your pelvis as some other single leg stuff.