We've all dreamed about it: A leaner, stronger midsection, preferably with that iconic six pack that seems to elude most of us. Of course, getting this is easier said than done--with an increasing love for crisps instead of the gym, our stomachs better resemble Bowling balls than a washboard. But don't give up yet--as with most things in life, this can be reversed.How to Build Stronger AbsAlthough diet matters more when it comes to making those elusive abs visible, they won't help you develop a more muscled midsection--and here is where core exercises come in. In years past people believed doing tons of crunches was the key, but now we know it's more about how you train them instead of how much you train them. For leaner, more muscled abs, give these exercises a try:1. Back extension. Lying on your stomach, keep your legs together while keeping your hands behind your neck. This is the starting position. Now slowly raise your chest and shoulders off the ground towards your hips, as if you're doing a reverse crunch. Hold this position for a couple of seconds before releasing.2. Plank. Start by lying on your stomach with your forearms facing the floor. Your feet should remain together. This is the starting position. Now slowly lift you body upward, using the momentum of your forearms and toes. Try to keep your body as straight as possible--you should feel your core tensing up. Hold this position for as long as you can, going for 30 second intervals to start.3. Reverse crunch. To start, lie on your back with your knees bent at a 90 degree angle. Keep your arms at your sides for support. This is the starting position. To engage your abs, slowly bring your knee inward towards your chest. Hold the position for a couple of seconds before releasing. For an extra challenge, try holding a medicine ball between your knee while doing this exercise.Remember, less is more--keep the repetition ranges short but intense to build those washboard abs.