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 ...

Halle Berry stunned her fans by flexing her biceps in her latest Instagram post, which caught them off guard. Last month, Berry had stirred up excitement with her bikini photos in a scenic sandy ...

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 ...