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 ...

The concept of a plank is pretty simple: You hold yourself up in a pushup position for a set period of time to work your core, glutes, and hamstrings—all muscles you need in order to run fast and ...

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 ...

When you think of Copenhagen, smoked fish and bike lanes might come to mind. But in the fitness world, it’s the name of a challenging side plank variation. A Copenhagen plank is a static bodyweight ...

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 ...

YOU KNOW THE SAYING: Work smarter, not harder. You may have already incorporated that mentality into your training routine, subbing unfocused, 60-minute workouts for strategic 30-minute sessions, or ...

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

Vanilla ice cream, a plain cheeseburger, that little black dress-sometimes keeping it simple is actually the most satisfying. That goes for the core move youve probably done in almost every workout ...

Add Yahoo as a preferred source to see more of our stories on Google. Love ‘em or hate ‘em, planks are a popular fitness move for a reason: they’re effective. This one move engages the entire body, ...