Tip: Build Your Butt With Bands

• You can put bands around the end of the bar, but I like to attach one to the rack so that it's providing resistance at the waist during the movement. It also acts as a cue to "get your hips through."
• Keep your knees barely bent during this movement, and use a controlled eccentric (negative) and a somewhat powerful concentric for each rep. You need to think about pushing your butt out and into the wall behind you while maintaining this "soft knee" position.
• old the top portion of the movement for a second before starting the next rep. You shouldn't look like you're dry humping the band. Do 4 sets of 12 reps.

First, it's easy to do wrong. You see guys load the bar with back-breaking weights, then barely bend over and squat down slightly. This sucks because the hamstrings don't lengthen enough in this position, and hip flexion is minimal.

Second, with a barbell the resistance is high at the bottom quarter of the movement and minimal at the top quarter. Ideally you'd want the resistance to increase as the concentric is performed so that tension doesn't diminish as much during the completion of hip extension. Banded good mornings fix the problem.