Adjust leg pad to contact lower leg just above the ankle. Adjust seat back to align knees with pivot point on machine. Sit in good body alignment (abs tight, chest up, back straight). Position legs to keep kneecaps on top. Lock top pad comfortably on quadriceps. In a controlled motion, flex the knees by bringing feet down and back as far as possible. Contract hamstring muscles fully without compromising form; avoid any hip movement. While maintaining the controlled motion, return to starting position without setting down weight or relaxing the muscles. Do not allow the knee to hyperextend.
Great exercises you can do using a leg machine.