This is a real quad burner if you do it right. Most bodybuilders don't; they keep the bar away from their glutes instead of holding it right up against them throughout the movement. Elevate your heels slightly and keep your upper body erect. Position the bar against your lower glutes where they join the upper hamstrings. Squat down until your thighs are about parallel to the floor. Come back up but don't lock out; keep constant tension on your quads. One more thing: Do nonstop reps. If you want burn, this will do it! Do three sets of 10-15 reps.