Forget Crunches — According to This Trainer, These Are the Most Effective Flat-Belly Exercises

• Start by lying on your back on a yoga mat with your hands beneath your pelvis .
• Engage your abdominal muscles by drawing your belly button in toward your spine and elevate your legs off the mat slightly This is your starting position.
• Inhale. Bend your knees and, using your abdominals, draw them in toward your chest, ensuring that your feet stay together (and your lower back on ground).
• Exhale. Slowly extend your legs to return to the starting position.

Kelsey recommends doing three to four sets of 10 to 12 reps each.