If you're using a mat, place it on the ground perpendicular to the elevated step.

Lie down on the ground (or on top of the mat) so that your body is perpendicular to the step. Rest your heels up on the step so that your toes are pointed up. Your legs ought to be straight and angled slightly out into a V-shape.
Tilt your pelvis under a bit and engage your core. This can protect your back from excess stress once you sit up.

From here, raise each arm out straight in front of your chest and use your core to raise your torso. As you sit up, reach your arms up, and then at the top of the sit-up, twist your body to the proper and reach your left hand toward your right ankle.

  • Come back to the center with each hand raised, and then use your core to lower your body back down.
  • Repeat, however, this time at the top of the movement, reach your right hand toward your left ankle.
  • Come back to the center with each hand raised, and then use your core to lower your body back down.

This is one rep. Do 15 reps

This move is “very difficult for many people,” says Oprea. To make it easier, position your body further away from the elevated step; to make it more difficult, scooch yourself closer. You can also make the move easier by performing it with your heels on the ground versus on the elevated step, says Oprea.

However, you do the move, concentrate on continual core engagement as you sit up and down and as you perform the twists. Keep it “nice and controlled,” says Oprea. “This isn't meant to be fast and slinging your body around.”

If you have difficulty balancing, stand close to a sturdy object—like a tree or bench—and gently rest a hand on top of the object for extra stability. To make the move harder, hold a set of light dumbbells in your hands as you squat.