How and why do leg curls on a gym ball?

The Swiss ball leg curl is a variation of the leg curl movement used to develop and strengthen the hamstrings.

This exercise ball exercise challenges the core to stabilize the body while contracting the hamstrings to bring the exercise ball toward the body.

For this reason, you will be less likely to cheat as you would when trying to increase the load used in a weight training exercise. The goal instead will be to execute the movement with good technique before moving on to a more difficult single-leg variation.

1. Get into a prone position with your feet on an exercise ball and your arms extended out to your sides.
2. Start the movement by flexing your glutes and extending your hips until you have a straight line between your heels and your head.
3. Keeping your hips extended, bring your heels toward your buttocks, flexing your hamstrings.
4. Slowly return to the starting position and repeat the movement until you complete the required number of repetitions.

Training tips

• Do not let your hips rotate as you bend your legs.
• Once you get used to this movement, you can also do unilateral work and increase the difficulty by working with only one leg at a time.