T Nation

Deadlift: Ached vs Non-Arched Back

not advocating arching back but, which one would allow you to lift more weight?

Arched or neutral lumbar spine with a little thoracic rounding usually lets you lift the most.

arches are stronger than angles

arched lower back,
bent forward a bit with the upper - reduces ROM - pulled tight during the rep.

It’s all individual though - google ‘Bob Peoples deadlift’ to see a weird example