On top of working your abs and obliques, this move also doubles as a great thigh toner. Plus it's a great modification for hanging leg raises, too.
- Lie flat on the ground with your legs extended straight up toward the ceiling. Place your hands underneath the back of your head. For added stability, place your arms out to your sides, allowing your palms to grip the floor (much like you would in a push-up position).
- Pressing your lower back into the ground, slowly lower both legs down toward the floor, then slowly raise them back up. If this is too difficult, lower them as much as you can or lower one leg at a time.
- Complete 10 to 15 reps.