Is lower back pain *on the bike* to be expected when really ramping up the miles?
 

I would say all of the above, but would not be complacent about it. Just my opinion as a medical guy and fellow sufferer, but I think a systematic and supervised program of core and posterior muscle chain strengthening is in order. Back pain, aside from being, uh, painful, means that you are at risk for things like acute lumbar disk disease, which you really don't want. One needs strength in areas that cycling is notoriously poor at strengthening in order to hold a flexed position comfortably and safely.

Lower back pain is likely one of the most common ailments most people will experience next to the headache. Almost everyone will have it at sometime or another for a variety of reasons. I'm tall but with a short torso so I'm no stranger to lower back problems.

As a cyclist your situated in an unnatural position which can certainly exacerbate any genetic issues you may already have (some are balanced for it more than others). But the same could be said of an office worker that sits in a chair for 8 hours.

The best remedy in either case is to supplement your riding with a good program of resistance training. The stronger the muscles in your lower back, the less pressure on your spine and connective tissue. Of course this presuppose you've already established the optimal riding position.

Get a fitting.

Do you stretch before/after? How tight are your hamstrings?
I had fairly severe back pain on my longer rides for many years. I had a good chiropractor (or so I thought at the time), who would somewhat help, but that would never really go away. The more I rode either mountain or road, the more back pain I had. I always attributed it to a herniated disc I had.
That was until I visited a physiatrist, who pointed out that my hamstrings are extremely tight and that causes most of my back pain problems. Took me several PT sessions to learn proper stretches and several months of daily stretching and while I still have my herniated disc problems, that does not bother me on a road bike anymore (technical/downhill mountain biking is a different story though).

I have a similar problem .... because my stomach and lower back are weak. When I ride too long on my racier bike, i can switch over to my endurance frame and be better .... so yes, the posture makes a difference. But ... I used to ride further on the racy frame with much less pain ... and I know i have lost fitness since then (injuries and less riding/exercising.)

For me, the answer is simply strengthening my core. You might want to see a doctor .... I am Not in a position to dispense medical advice ... but if I were you I would look into core-strengthening exercises. They are a good idea as we age, whether we ride or not, anyway.

Also ... 45 is not the issue, but less flexible is part of it. Plenty of people do advanced yoga at 75. Don't look at your age as a barrier. The extra weight doesn't help, but isn't the real problem .... the muscles support you, not the fat (and I am something of an expert in this field. :( )

if you are doing this ride soon, consider changing your set-up ----add some spacers and get the bars up until afterwards. Just a little change in center of gravity and body angle Really adds up.... i did back-to-back 40+ mile rides this weekend and after the first one, on my racy frame, i could barely tolerate the discomfort, but I went a few miles longer the next day on the more relaxed frame with almost no discomfort.

The cockpit is the easiest and quickest change to make ... you will likely not gain significant core strength in a few weeks. Raise the bars, maybe move them back a centimeter, ride your century, and then work towards greater strength and a more aggressive position at your own pace ... is what I have been doing.

I'm not a medical person, but my fitter tells me my hip flexors are stiff as a board (very common for cyclists). Stretching them out makes a pretty big difference for me. Since the hip flexors are attached to the lower back, I'm pretty confident that's the issue for me.

Good luck!

Yeah, stretching the calves, hams, and glutes if they're tight is a good idea.

Tom Danielson's "Core Advantage"
 

Bit of a broken record on my part...but since my sciatica is mostly gone...

​​​You might find this book helpful...
https://cimg3.ibsrv.net/gimg/bikefor...c0b079f563.jpg
Tom Danielson's Core Advantage: Core Strength for Cycling's Winning Edge

https://www.amazon.com/Tom-Danielson.../dp/193403097X

Tom and his co-author also discuss the impact of overly tight hamstrings, as vtje mentioned above, on your lower back muscles and how this can distort you lower spine.

Cycling doesn't really use the hamstrings, so ours tend to be under-developed compared to the rest of our legs. What you describe isn't uncommon. Romanian deadlifts are great for the hammies!

No. Shouldn't be any pain.

Barbell squats have done more for my core strength than anything else. Renegade rows are probably a close #2 . I've been doing RRs for a month now, I feel some happy benefits.

https://anytimestrength.com/wp-conte...w-1024x768.jpg

if you can get into that position you don't need to worry about core strength. :D

Not normal.

Longer distances w/ lower riding position sounds like a likely issue.

IME, back pain is often associated with tight hamstrings & weak abs, pulling the pelvis out of alignment.

Yup, nor the glutes, which support the lower back directly.

I do lots of deadlifts of various kinds and goblet squats. For the anterior muscles I too love plank rows (never seen them called renegade) and the ab wheel. God, I love the wheel!

Get. In. The. Gym.

Lots of (most?) cyclists do nothing for their core and upper body. Your #1 suspension system for your upper body is your triceps. Your #1 support system is your core. If you do zero training in these area, then yes... you're supposed to have pain.

But. I. Don't. Like. The. Gym.*

*I do them at home.

That and being too fat, can't look back in a dropped position, is why I ride upright on a cruiser. Know this is road cycling but don't kill yourself unless you are racing.

Raise your bars a little, stretch your back some, and heed Clint Eastwood's advice:

http://shootinginlipstick.com/wp-con...imitations.jpg

Is this where you pay a Romanian to do your lifting for you? I think I could get on board with this type of workout.

Thanks for all of the replies! I knew I could count on you folks!

I absolutely don't do "enough" (any) core strengthening, and I'm not limber in the slightest. I'll work on both of those post-haste. I may even take the advice to pop a spacer back in while I finish up training to ease off on the geometry until I can get my core built up.

Thanks again everyone!

PS @chainwhip, I ordered the book!

Oh, man. So I do those 3x per week on my lunch break, but entering stuff into my Garmin as I go means getting in and out of that position like a dozen times. :o

Are those guys outside Home Depot Romanians?

It's a variation on the deadlift that's really easy to do, and works your hamstrings more and glutes less. It's less taxing than a standard DL.

https://fitnesscrest.com/romanian-deadlift-vs-deadlift/

I'm with you on living the good life, and avoiding useless toil. But this stuff pays off in a big way. Even just a little of it.

I think to answer OP's question though, yeah, lower back pain is to be expected while on the bike, at least during hard efforts. Along with your legs, arms, shoulders, calves, and everything else.

But if you're cruising along at a casual pace, not out of breath or anything, and your back hurts in any way, that's not good and is a problem that will need to be studied a little, but should be able to be remedied by way of adjustments to yourself and to the bike.

This is assuming no previous lingering injuries or genetic back abnormalities.