It's likely that the last time you swirled a hula hoop around your hips was on the middle school playground or your backyard when you were an 8-year-old. But much like the varsity jackets and chunky sneakers of the 90s, the hula hoop is making a comeback — and it's reinventing itself as a sassy piece of fitness equipment. Fitness experts explain why everyone should be hula-hooping their hearts out, as well as tips for how to hula hoop for fitness (and fun!).