Dead lifts are a great way to tighten your gluts and quads, but rank as the number 1 exercise that causes injury to your back.  To avoid injury keep your shoulders back and stick your butt up.  This will ensure that your gluts are doing the work. Tighten your butt as you come back up to a stand to get that extra burn.  If you feel it in your back...you are doing it wrong!  And remember based on your flexibility some people may be able to go all the way down the floor while others just passed their knees.  That's ok!  Work in your zone of comfort and in time your flexibility will increase.