I have a huge problem with rounded back on the deadlift off the floor only.
At the beginning I thought its technique problem, but today after 2hour session with lightest barbell (1 biggest plate per side) i found that its more likely to be mobility problem. I just cant reach the barbell without rounding my back.
I can deadlift heavy from about ~3inch boxes no problem with perfect straight back, but without boxes i cant reach the barbell i felt that my arms are too short, and i must round my back to reach the barbell.
I even put on the bar way too much weight and for like half an hour I tried to get good set up only, but i just cant, my back was rounded every single time.
Is it sounds like a mobility problem? If yes how to fix it?