The flat back deadlift is the standard technique most people use, or strive to. By pulling your lats back, taking the slack out of the bar and making a proud chest, you’re able to maintain a nice straight back position.
The lats back (flat back) position is difficult to maintain with heavy weight.
The round back deadlift is great for more advanced lifters wanting to move really heavy weight.
Start with your upper back rounded and keep a neutral low back position.
With the round back deadlift you start with your shoulders down and lats in the front pocket — a much easier position to maintain and allows you to shorten the ROM.