can i see a pic of you on your bike?

---

Dan Empfield
aka Slowman

1. Did you have a assessment of your movement to determine any areas of weakness, asymmetries, or imbalances?

2. Are you correctly loading and progressing your strength program? Is someone doing this for you, or are you on your own?

3. What are you doing currently specifically strengthen your trunk and lower back?

4. Are you doing those exercises correctly, or do you think you are doing them correctly?

My blind, SWAG would be:
Saddle is too high.

To explain the difference between the trainer and the road, my guesses would be:
a. You are sitting up on the trainer more.
b. You are sliding back on the saddle while outside.
c. You are having to stabilize the reaching caused by the saddle being too high more outside than when fixed on the trainer, causing your back to fatigue more outside.

Could be one of those, could be all of those, could be none of those.

I'd lower the saddle 5 mm and see how it goes.

And has already been requested, pictures/video would be tremendously helpful.

---

Trent Nix
Owned and operated Tri Shop
F.I.S.T. Advanced Certified Fitter | Retul Master Certified Fitter (back when those were things)

I routinely get lower back soreness when I switch over to my road bike and add a lot of outdoor climbing. It only comes up on my first few 5000+ ft rides then my body adapts. Always figured I'm just twerking my body different both in and out of the saddle which I don't do to nearly the same extent on TT or trainer.

I have a Kickr and do almost all of my training indoors. Last year at the beginning of a longer session 10 minutes in I do the calibration and immediately after my belt snaps. Not having a spare belt and not wanting to throw away the session I switched over to my old trainer which is a Kurt Kinetic Rock'n Roll (the kind that sways back and forth like you would riding outside rather than being fixed) and went on about my few hour ride, which I'll add was all in aero position. The next day I found that my lower back and sides were sore. I'd done the same workout plenty of times before and that was never the case. I chalked it up to the fact that when riding a fixed trainer your core stabilizer muscles aren't doing much work compared to when the bike can move freely side to side, especially in aero position when your shoulders and arms are doing much less stabilizing work than when riding upright. Doing core work helps, but the duration on a long ride is something that is hard to replicate. After a few sessions on the RnR I didn't notice it any longer so my guess is that could be the case with you as well, at least something to think about anyway.

I will get a photo tonight and upload