Lie face down on a leg curl machine and lock your heels under the foot pad. Make sure your legs are fully extended and the foot pads are resting on the back of your ankles.
If the machine is equipped with handles, grip them. If not, grip the front of the pad you are lying on.
Remaining flat on the bench, with no arching of your spine, curl your legs up in a smooth arcing motion by bending your knees until your hamstrings are fully contracted. Hold for a count of one.
Slowly lower your legs to the starting position in a smooth arcing motion.
Don't use so much weight for this exercise that you need to swing or jerk the weight up. Doing so can cause injury to your lower back and / or hamstrings. Start with a lower weight until your strength increases.
Standing tall with a tight core and flat back, hold a barbell or a pair of dumbbells in front of you. Hands should be slightly wider than shoulder-width.
Maintaining a tight core and flat back, bend your knees slightly and push your hips back. Keep your arms extended and the weight close to the body. Once you feel the contraction in the back of your legs, slowly return to the starting position.
Place a barbell on the floor and stand facing it with your feet shoulder width apart, toes pointing forward and your knees slightly bent. This is the start position.
As you exhale, bend at the waist keeping your back straight and knees slightly bent until you feel tension in your hamstrings.
Grasp the barbell with an overhand grip. Your arms should be fully extended with your hands spaced shoulder width apart.
Lift the barbell by extending your hips and waist in a smooth action until you have returned to the upright position, inhaling as you do so.
Pause for a count of 1-2.
Return the barbell to the floor or just above it by repeating step two.
This exercise should be avoided by those who suffer from lower back problems. To avoid injury, keep your back and torso straight at all times throughout this movement. This exercise can be performed using dumbbells or a straight bar attached to the low pulley of a cable station.