Now that my training is becoming more and more outdoor based (improving weather conditions) I’m noticing that after around 90 minutes in a ride I start to develop lower back pain on one side (left if that matters at all)…
Strangely this does not occur at all when using the same bike indoors (on a direct drive trainer). Does anyone recognize this or perhaps have an idea on the cause? My first thought would be bike fit, but what boggles me is the fact that it doesn’t bother me inside. Perhaps important to note that outside I spend a lot of time with fairly strong head/side winds (living by the Dutch coast).
Assuming bike fit is NOT an issue, this points to what I think could be the issue for you and others.
Much of this might boil down to differences in gearing, cadence, inertia and the like.
Trainer Use:
What trainer do you use?
What trainer mode (Resistance or ERG)?
What gearing are you using?
What cadence (main and range)?
What body and handlebar position is used mainly?
Outside Use:
What gearing are you using?
What cadence (main and range)?
What body and handlebar position is used mainly?
If I were to guess, higher wind may lead to you using a lower body position, maybe lower cadence, which might shift the loading on your body, compared to inside.
Essentially, find what is similar and what is different, and that may help find what is leading to your issues.
I often get lower back ache on one side (right one) when riding outside if I don’t stretch before the ride. Usually it happens if there is a lot of high power surges during the ride or if I’m riding MTB.
I noticed that doing a few hamstring stretches before the ride helps to eliminate it.
I don’t get the same issue when riding indoors either.
I try and maintain similar cadence in both situations but as you said there are many differences that come to mind.
I spend most of my time in the drops outside, inside this happens far far less.
ERG mode inside which smooths everything out, outside is pretty “spikey” in comparison especially during unstructured rides.
I’m considering spending some time in a week doing lower back exercises to improve strength in that area. 5 months of indoor work have probably mostly neglected that area.
Last few of my rides did have a bunch of big surges to get over tiny bits of elevation and I never do any stretching beforehand so you might be onto something.
The back training is likely a good idea regardless. But what I think this points out that you ride “high position” inside and “low position” outside, which is an important difference. Typical recommendation would lead to making sure you do at least some work on the low position, since you apply it plenty outside. Keep the positions more similar, and you close the gap a bit. Still, things like trainer to real world differences may lead to differences, but it’s a matter of trying what is practical to keep them similar.
Actually had a similar experience. On a trainer you don’t really engage your core since the bike is held upright, but outside requires core to stabilize the bike. When your core gets tired this shifts the load to your back! For me, using a rocker plate inside made a large difference. Now my indoor rides also use my core, which helps prep it for outdoor rides. Alternatively use rollers, if you are brave! (I’m not)
I’d echo @Brett_G on the core weakness. I’d back pain last year as well after months indoors on the trainer. I found dropping the saddle 1cm helped in the short-term. Started core work and glute activation exercises and slowly raised the saddle back up over a few weeks.
I also got a rocker plate this year as well, and have been a little more disciplined on the strength work, found both help.