I have a standing desk, so my chair is a stool that kind of looks like an Aeron chair. It has a reclining back, and that's been the key for my lower back. Reclining while sitting takes pressure off the lower back.
Reclining Is Good For Your Back
I actually tweaked my lower back this week...happens every so often from the most innocuous activity. I can go to the gym and deadlift 345 and no problems. Then I destroy my back for a few days by reaching for my cell phone the wrong way. Anyway, this has been a killer product for getting the knots out of the hip and lower back area. It's called the Mauler for good reason.
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A few sessions and I feel much better. Foam rolling is the truth.