If you want killer abs, then you have to work on them. Men's Health gives you the expertise advice on improving your abs. Try this "pulse up" exercise that helps beginners strengthen their core muscles.
Lie with your hands under your tailbone and extend your legs straight up towards the ceiling perpendicular to your torso. Lift your hips off the floor in a straight line, pause, then lower your hips.
Breathe out as you push up towards the ceiling, squeeze the abs and breathe in as you slowly return to your starting position. At the bottom of the movement avoid resting your backside on the ground and instead aim to keep tension in your abs at all times.
Too easy? Ask your training partner to push down on your feet to help apply some gentle resistance.