My lower back k is garbage.The only thing I can do that won’t irritate my lower back is hanging leg raises.
I just did dumbell rdls and I am in hell.
But I just started...gonna do some Nordic hamstring curls now.
I like to use the leg raise bench, where you can plant your arms and raise your legs, but I grab a 20# dB with my feet as I do it and focus on the negative.