Beth Skwarecki is Lifehacker’s Senior Health Editor, and holds certifications as a personal trainer and weightlifting coach. She has been writing about health for over 10 years. Double unders are ...

Add Yahoo as a preferred source to see more of our stories on Google. That last point is no small thing. If you’ve ever jumped rope for more than 30 seconds, you’ve felt its muscle burning, endurance ...

What do AMRAPs, Fitaid, and No-Bulls have in common? Welp, they’ve all been popularized by the sport of functional fitness (also known as CrossFit). And there’s one more biggie to add to the list: ...

Jumping rope is much more than a playground pastime. Just ask Molly Metz, a five-time jump rope world champion, who has done roughly 1,400 unbroken double-unders (that's when you turn the rope ...

While double unders are Molly Metz’s bread and butter, she promises there are more to her CrossFit workouts than jump roping’s less-liked sibling. “Even for me, sometimes I get sick of double unders,” ...