The single leg hip raise off a bench is a great way to fire up the glutes and get hip extension power. This is also where a lot of your power will come from.
First, practice with 2 feet on the ground. Be sure that the body is only hinging at the hips, and not at the low back.
Second, I use the band because it forces the working knee to cave in, which in turn forces you to push against that resistance. In other words, it gets more muscles involved!