In this short video, the good folks at AsapSCIENCE explain the effects of myostatin, a protein that inhibits muscle growth past a certain point. If you've ever had friends who work out a little and gain a lot of muscle, this video may help temper your frustration at that effect. And no, there is no snake oil you can buy (yet) to change your own myostatin situation. Learn up:
Related is this 42-minute TLC show about Liam Hoekstra, a kid with a rare myostatin-blocking genetic condition (and resulting impressive strength). This video is a few years old, made when Liam was 3 years old. Today he's a wrestler in grade school.