8. Ball Crunch:
- Lie with your lower back on the ball.
- Keep your arms crossed on the chest or back of the head.
- Pull your abs to take off the torso above the ball. Also pull your bottom ribcage downwards to the hips.
- Take a precaution to keep the ball stable without rolling.
- Get your back to the rest by stretching your abs.
- You can repeat this 1-3 sets of 12-16 reps.
An exercise ball is the best way for abs strengthening. This can also be used for floor crunches and is available in most of the gyms these days.