This sit-up variation puts your hip flexors at a disadvantage, forcing your abs to work harder.
- Lie on your back and open your legs into a diamond shape (aka butterfly legs) with the soles of your feet pressed together and knees out wide. Extend the arms overhead.
- Inhale to curl the torso up, and tap the floor in front of your feet to stretch your glutes a bit.
- Slowly lower back to the starting position.
- This counts as one rep; do a total of 10 reps.
Image Source: POPSUGAR Photography / Kyle Hartman