Position your body in the leg extension machine and adjust the leg pad so that it is resting on your ankles. Grip the handles and fully extend your legs until you feel a full contraction in your quads. Pause briefly at the top to squeeze your quad muscles and then lower the weight back to the starting position.
Tip: Remember to use a full range of motion on this exercise by fully extending your legs and getting a good stretch at the bottom. Do not allow your legs to rest at any point during the movement because this will take the tension off of your quads and will decrease the amount of muscle stimulation you can achieve.