I’m in SW Ohio, so most rides are fairly flat or on short rollers. This year my monstrous rides are out of state and involve more climbing than I’m used to doing. I just got back from the Asheville Gran Fondo (brilliant event), and got a big dose of lower back pain during the climbs. This doesn’t bother me on the flats at all, and even went away after the climbs ended and I descended or was riding hard on the infrequent flat sections. I had the same symptoms on a hill I was training on in OH, that was much smaller of course, just a 8-10min climb. After Asheville it took around 5 days, to really work the discomfort out of the back. The pain isn’t centered on the spine, it is either side and the same on left and right.
I doubled down on regularly doing foundations leading up to Asheville, and added in some planks, but this wasn’t enough. I also employed a decent climbing cassette (11-36), to avoid most of the grinding and was able to spin at decent cadences up all the hills.
Next up is 6GAP in 9 weeks time. I will be doing a lot more climbing sim rides, using the indoor trainer and zwift to help with this, and will elevate the front wheel . So hopefully I’ll get a better handle on what’s causing the pain and a solution.