Crunches are a familiar movement that you can easily do from the comfort of your own home or in a gym setting. This quick, 15-minute (or less!) series can be completed with minimal to no equipment.

Bore your core? If the only way you’re training your abs is by doing crunches, you might. Having an arsenal of abdominal exercises is essential to keeping your abs strong and your movements graceful.

But often, whether it's pulling on jeans or wearing a swimsuit, sucking it in is all we've got. And we all know how effective that is. With diligent work, though, you can strengthen and flatten those ...