Lay face down on a leg curl machine with ankles under roller pads. Adjust the pad to just above your heels and the lever arm to your height.
Sit on the leg curl machine with your legs straight and ankles against the roller pads. Set the machine to your height and fasten the lap pad to your thighs.
Position one leg beneath a leg curl machine pad and secure the ankle strap if using a cable machine. Contract your hamstrings to curl your leg up toward your glutes, stabilizing your body.
Lay on your back with your heels on a Swiss ball and arms by your sides for balance. Lift your hips to form a straight line from shoulders to heels.
Do any of the aforementioned exercises with one leg: supine, seated, standing, or Swiss ball curl. Keep your hips level and form consistent to build leg strength equally.