Sara Sigmundsdottir is an Icelandic CrossFit athlete and one of the sport's biggest stars. Training her core is key, and she works her abs at the end of every session, she told Insider. Sigmundsdottir ...

A gymnastic staple that more then meets the eye, hollow rocks teach you how to stabilize your midline and brace the spine for a plethora of other full body movements. When done properly, the hollow ...

Youve never needed any elaborate equipment or gear to build rock-solid core strength. Sit-ups, leg lifts, and hollow body holds and rocks have always done the trick. But that doesnt mean you cant ...

Strengthen your core, hips, quads and back using this abs exercise to build full-body strength, endurance and stamina. The hollow hold is an isometric exercise, which means your muscles contract ...

Gymnasts are not just textbook strong; they flip their bodies around defying gravity, so their biceps, abs, and quads need to be downright powerful. Trust me: I slipped on my first leotard at 4 years ...