The clamshell strengthens your hip muscles and pelvic floor while (bonus!) balancing the strength of inner and outer thighs, Bonney says. "This move is especially good for runners, as a lot of our ankle and knee alignment comes from the pelvis and hips being stable," she says.
How to Strengthen Your Core With Clamshells:
- Lie on your left side with one leg stacked on top of the other, knees bent at about a 45-degree angle and your feet in line with your hips. Rest your head on your left arm.
- Brace your abs or draw your belly button in toward your spine.
- Keeping your feet touching, raise your right knee as high as you can. Be sure not to shift your hips or pelvis. Your lower leg should remain in contact with the floor.
- Hold for one second, then return your right leg to the starting position. That's one rep.
