Your back is set correctly in all these reps.
Quick background. I was making decent progress with my deadlift but as I drew closer to the 400 pound mark, my lower back felt increasingly fatigued, culminating a complete stall at 395 pounds. I recorded myself the following week and realized my back was not even close to being set and that I was pulling with a rounded back.
I am determined to correct this issue so I took over 100 pounds off the bar with the focus on getting my back position set. I also came to the realization (thanks to an older article from Rip) that my four inch belt, while perfectly suitable for my squat, was a big part of the problem for my deadlift back position. I purchased the Starting Strength three inch belt and am using it for deadlifts going forward. Even though the weight is relatively light for me here (280 pounds), I am pulling with the belt to get used to setting my back with the belt on. My hope is that I am getting closer to getting the starting back position right, but it is still a bit of a struggle for me (as I'm sure you can ascertain from the clip).
Apologies for the portrait orientation but my garage gym is too confined to film in landscape.
Thanks in advance for the feedback.
Deadlift Form Check #1 - YouTube
Your back is set correctly in all these reps.
Thanks Rip, glad I got this fixed. Ditching the four inch belt on the DL was huge for me so thanks for that advice as well.