Tired of that stubborn belly fat? Get ready for a radical change with our 21-day plank challenge. This isometric exercise, ...

Erin Stern, a two-time Figure Olympia champion, broke down her calorie-burning back and abs workout for achieving a smaller waist.

With 7.6 million views on YouTube and the claim it’s the hardest abs workout ever in the title, I had to give this 9-minute ...