If you are looking for a real challenge, then try doing the RKC Plank. Invented by a former Soviet special forces trainer, ...

"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." When you think of Copenhagen, smoked fish and bike lanes might come to mind. But in the fitness world, it ...

Spoiler alert: There is <a href="https://www.womenshealthmag.com/fitness/a19909906/what-it-takes-to-get-a-six-pack/" id="8cce8813-8264-31a7-acbf-afc9c065e83e"> no ...

Planks and jumping jacks are perfectly fine workout moves. But if you combine the two together, you can actually get an even better total-body workout. Meet: the plank jack! Plank jacks involve ...

Burpees are a popular exercise, but they can put a lot of stress on your joints. You can swap burpees for other lower-impact ...

Pilates pro Simone de la Rue demonstrates how to do a plank jack—aka the ultimate cardio and core-strengthening move—with proper form. A little known fact about planks: In addition to working nearly ...

If you’ve ever tried them, you know side planks are challenging­—even more than regular planks. But they’re a critical move, says Keli Roberts, an exercise physiologist with the American College of ...

Why one trainer calls the plank variation "no joke." ...