Leg press, close stance murders.some tips for legs...when it comes to working quads (unless it's dangerous...squats or front squats...things where balance is important) push with the balls of your feet with feet close together and see if you feel those puppies working more. Hams as Dante told me...put feet high and wide as possible and push with heels....sorry for the rant
I personally enjoy putting my feet lower on the sled.
Another "tip", over emphasize the heel motion. Sometimes i even lift the top of my foot on my heel at the top of the motion.
I try to almost get most of the pressure on the heel