Flat six-pack abs seems to be what everyone strives for when they hit the gym or get exercising. And why not? A strong core is the cornerstone of a healthy and strong body; toned abs look great; and a midsection without body fat is an excellent way to reduce the risk of obesity, diabetes, and other diseases. There are a lot of late-night TV ads out there touting the latest and greatest in ab-building technology. But the best ab exercises take hard work and proper execution to get rock-solid results. It ...