Your favorite ab-building machine at the gym may be causing you more harm than good. That's right—we're talking about the torso rotation machine. This is the Chubby Checker–inspired ab machine you sit ...

Women's Health may earn commission from the links on this page, but we only feature products we believe in. Why Trust Us? That said, different ab machines function in very different ways, so it's ...

Try these four daily walking variations to engage your core, improve posture, and help flatten your stomach after 50.