Lower back pain only mountain biking
 

Hello everyone.

I have a strange problem regarding lower back pain. On my road bike, there is about 6-7 cm of drop between my seat and handlebars and I am quite comfortable. I easily ride in the drops and ride aero with my forearms on the bars all the time. My back never hurts.

On my gravel bike, the geometry is different and there is only 3-4 cm of drop between seat and handlebar. I noticed that before I slammed the stem on my gravel bike, my lower back hurt (felt like muscles got tired). Then, as soon as I lowered the stem on my gravel bike and increased the drop between seat and handlebars, my back pain almost completely went away.

This brings me to my main problem. On my mountain bike, a 2019 Stumpjumper, I get lower pack pain after only a few miles in the trail.

I’m not sure if this is attributed to the different geometry (the bars and seat are pretty much level) or just mountain biking in general with different forces.

The backpack I wear might also contribute, and I am considering using a hip pack instead of a backpack hydration pack.

Any thoughts? I cannot lower the handlebars any more, and the bike is definitely the right size for me (I’m 6 foot tall with a wingspan 2+ inches wider than my height, and the bike is a size large).

Thanks,

John

As a near lifetime back sufferer, what has helped me the most is core exercises. I do these daily and have for some time. However, in your case, it would seem there is a difference in the geometry of the bikes that cause or contribute to the problem. I would spend some time taking careful measurements of your bikes to compare that geometry. Especially, I would compare the distance from where your sit bones rest on the saddle and the pedal spindle at the forward three o'clock position. Good luck with this. I know getting the best fit can be frustrating.

Thank you!

The other weird thing about my problem is that I am only 19 years old!

I biked about 11,900 miles in 2019, including several 100 mile rides on my road bike with complete comfort.

I had a similar problem when I rode a mtb BITD. I never resolved it, took plenty of Alleve. Good luck!

If your parents' insurance will pay, you should seek out a good sports physical therapist to diagnose this. At that level of riding ^ you're likely suffering the consequences of overuse, which may include tight hamstrings, general muscle shortening. This could be in the hips, glutes, or (most likely) cause interaction between that shortening and your body's compensation from other muscles, like your piriformis or deep spinal muscles.

Time to consult experts who are trained in this.

The symmetric cycling position and riding a more upright fatbike (rigid) year round seems to help stretch out my back.
I have more neck-trapezial muscle issues that worsen w/ road biking. For shorter mtb rides that require more than a liter of fluid I use a Wingnut Gear pack (hip style) with incompletely filled 3 liter bladder but for longer, sustained sojourns I use handlebar buckets for the 1 liter Zefal water bottles....with all of the above suggestions, seems you may wish try a series of mtb rides without any pack first (to assess the amount of back discomfort and mtb position-likely, you don't use any pack while road cycling).

fwiw - maybe the 1st 2 bikes allow you to have a straight back, whereas the MTB requires a more conscious effort. maybe take note of your back position on the MTB?

I don't ride with my road bike set up like yours (my bars & saddle are closer to the same height) so I have make a conscious effort to ride with a straight back. I never actually achieve it but, mentally, (after reading a tip on the forums) I try to stick my butt out. it feels awkward at first, but the result is a straighter back & my butt is never actually doing that. I've checked, as I rode past large storefront windows to check my posture

my son's back bothers him when we ride. he's the only one in the family who complains of this. he is also the only one in the family who rides with a hunched or curved back. everyone but I have a "hybrid" so they're not riding road bikes in a low aero position. he's been working on his back posture (hinging at the hip instead) & he seems to complain less the past few years. he's now in his early 20s

maybe some tips here can help, you may be on to something with the backpack issue ...? How To Stop Back Pain When Mountain Biking

good luck!

Everybody's built differently, so my experience may not apply to you, but I bike commute with a backpack. On two bikes I rack my pack, but on my rackless, old 12-speed I wear my backpack. Of course being a road bike I am leaning well forward, but you may be able to do that on your MTB bike with some adjustment. I loosen the straps almost all the way and let the weight of it rest on the small of my back. It has no waist or hip band, just the shoulder straps, so it rocks back and forth a little,and yet it stays in place. I'm about to turn 58 and this causes me no back problems.

The other thing I'll mention is that after 22-years, I converted my straight-bar, MTB-based commuter to drop bars this fall. (Jeez, the bike's older than you!) My hands no longer tolerate straight-bars, and they have been as happy so far on the new drops as they have been on my two other drop-bar bikes.

Same seat, same pedals and cranks, but now I notice my hips also no longer bother me riding in the new position. They weren't screaming, but they would feel a little tender and "achy" after riding.

To recap, I let my backpack rest on the small of my back...and a change in riding position resulted in greater comfort.

It sounds odd that at "only 19" your back would be giving you problems, but again , everyone's different, and you did bike almost 12,000 miles in 2019, so even if you are comfortable in the road bike position, you may be putting a lot of stress on your back.

Good luck and enjoy yourself!

The issue may be more of a horizontal reach issue than a bar height issue.

Pay attention to what you pelvis and lower back are doing on the mtb vs the road bike. If your pelvis in tilted more forward and your lower back is flatter on the road bike, that may indicate you need more reach on the MTB.

If the reach is too short, you may end up curving your lower back and tilting the pelvis back in order to shorten your body’s reach. if you think this may be the issue, just try a longer stem and see if that helps.

Also, what bar width are you running? A wider bar can have the same effect as a longer reach.

BTW, when you say you can’t lower the bars any more, does that mean you are already using a zero-rise flat bar with the stem flipped upside down?