Rounding back during deadlift

[PatricioMelendezCongrains]

Hello,

I have a question about the deadlift form. I’ve noticed that some athletes allow slight upper back rounding during their lifts as long as they maintain tension. I instinctively tried this in my last session, and it felt pretty good.

I’m providing two links for reference: the first is a set of 3 reps at 375 lbs with my old form, and the second is three reps at 390 lbs with a slight “round back.” I would greatly appreciate your feedback on whether it’s acceptable to have some rounding in the upper back.

- Deadlift x 3 / 390 LB - YouTube. - 390LB
- Deadlift x 3 / 375 LB - YouTube - 375LB

I appreciate any help you can provide.

[Mark Rippetoe]

It is common to see some thoracic flexion in very heavy deadlifts. These are not very heavy, nor are they very round. Thoracic flexion shortens the distance between the bar and the hips, which makes a shorter moment arm to operate. I would advise against this in training. If you want to try it at a meet, fine.