Meet Liam Hoekstra, one of the very very rare people to have myostatin-related muscle hypertrophy, or muscle enlargement:

Liam has the kind of physical attributes that bodybuilders and other athletes dream about: 40 percent more muscle mass than normal, jaw-dropping strength, breathtaking quickness, a speedy metabolism and almost no body fat.

Lest we all become too envious, it's important to keep in mind that, while his soft-tissue changes make him seem almost superhuman, his skeleton, and most importantly his joints, have not changed at all. Like a car, the human body is an intricate, inter-related system. Also like a car, beefing up the power without simultaneously strengthening the support structures results in something fun, but fragile.

To put it another way, there's a reason professional athletes in strenuous sports end up being forced to retire due to injuries, and it's not always the fault of physical contact.