Leg Press 

The leg press is an excellent exercise which primarily works the quadriceps and glutes with secondary emphasis on the hamstrings.  Most gyms will have either a 45-degree angled leg press machine or a Universal or Nautilus leg press machine.  Place your feet on the platform a little more than shoulder width apart and toes slightly outward while grasping the handles for support.  It may be necessary to adjust the seat prior to beginning.  Slowly lower the weight slowly to your torso but don't forget to breathe during the movement.  When your legs reach your torso you can push the weight up toward the starting position but don't lock your knees at the top.