How do you properly use the leg curl machine for an effective workout?

To properly use the leg curl machine for an effective workout, adjust the machine to fit your body size, lie face down on the machine with your legs under the pad, and curl your legs up towards your buttocks while keeping your core engaged. Slowly lower your legs back down and repeat for a set number of repetitions. Make sure to use a weight that challenges you but allows you to maintain proper form throughout the exercise.