Aaron Small, Master Personal Trainer Athletic Club Northeast: Gym Smarts: Lower Body Leg Press Lying Down This is the leg press laying down on your back. What it works is your gluts, hamstrings, and your quads muscles. You need to check to see if it needs to be adjusted. if its too far away, you want to pick up the lever and slide this down. When you lie down on your back you want your knees and hips at an angle 90 degrees. You want your feet to stick up just a little bit so that your knees don't go in front of your toes as you do the leg press. Make sure you are in a comfortable 90 degrees. When you are ready you will push up and don't want your knees to lock. You want to lower right before the weights stack hits. When I say your knees should not lock, I am referring to this. That can cause a knee injury.