1. Russian Twist
Lie on your back and lift your back and legs, such a way that body is balanced on the butt only. Your back should be straight, while your knees could be a little bent. Extend your arms above your chest and then move them from one side to front and back to another side, while maintaining same position for the rest of your body.
2. Elbow to Knee Crunch
Lie on the floor and keep your hands behind your head. Next you have to bend your knees and put left ankle over the right knee and then bring the right leg towards your chest. Tighten your abs and hold the position for about 30 seconds. Now switch the sides and repeat. Perform a few sets.
3. Diagonal Plank
This plank is going to be intense. First you need to get down on all fours while keeping your body in a straight line. Make sure that your feet are shoulder-width apart. Next, raise right arm and left leg at the same time. Hold the position for 2 seconds and switch the arm and legs. Repeat.
4. Reverse Crunch
Lay straight on the floor and keep your legs perpendicular to the floor. Then, raise your hips off the floor, bringing your legs closer to your chest without bending your knees. Maintain the position for a while and repeat.
5. Cross Body Mountain Climber
Get down on all four again, like a plank and extend your arms under the shoulders. When your body forms a straight line, lift the right knee bringing it towards your left elbow. Then after lowering it, do the same with opposite arm and leg.