Although male kangaroos do appear to flex their muscles to show off their impressive figures, researchers in a 2013 study said it is not currently possible to determine whether or not such behavior is ...

NO MATTER YOUR fitness goal, efficiency should always be one of your top objectives. Yes, the exact nature of your split will ultimately depend on what you're trying to accomplish—whether that's ...

Any gym-going female human knows just how much men like to show off their muscles. But it turns out that it’s not just male humans who think that flexing their biceps at ladies is an effective ...

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. Curls are the classic ...

NO ARM DAY WORKOUT is complete without a solid biceps pump. The big arm muscles are one of the most popular points of focus for mass-obsessed gym bros, and for good reason. The biceps take up a prime ...