Lie on your back with your arms by your sides, palms pressing into the floor, and your knees tucked in over your chest. Curl your hips off the floor and drive your feet straight up toward the ceiling, extending your legs until your body is stacked vertically from shoulders to toes - then lower back down with control, bringing the knees in as your hips return to the floor. The lift comes from your lower abs curling the hips up, not from swinging the legs for momentum.

Works: abs, obliques, hip flexors

Breathing: Exhale as you drive your feet up, inhale as you lower back down.

Common Mistakes: Kicking the legs up with momentum instead of curling the hips, letting the legs drop fast on the way down, and loading the neck by rocking too far up onto the shoulders.

Make Easier: Lift your hips just a few centimeters and keep the knees bent, building the range over time - or master Reverse Crunches or Leg Raises (Floor) first.

Make Harder: Pause at the top with your toes reaching for the ceiling, lower to a slow three-count, or move on to Windshield Wipers.