Lie on your back with your knees bent, feet flat on the floor, and your hands lightly supporting your head. Curl your head, shoulders, and upper back off the floor by contracting your abs, hold the squeeze for a moment at the top, then lower back down with control. It's a short movement by design - your lower back stays on the floor and your abs do the curling, not your neck and not momentum.

Works: abs

Breathing: Exhale as you curl up, inhale as you lower back down.

Common Mistakes: Pulling on the head and yanking the neck forward, lifting the lower back off the floor and turning it into a sit-up, and dropping back down instead of lowering with control.

Make Easier: Cross your arms over your chest and shorten the range - even a small controlled curl works the abs if you squeeze at the top.

Make Harder: Pause for a two-count at the top of every rep, or move on to High Crunches or Air Bike Crunches.