Since the beginning of time, one rule has governed the existence and evolution of all living things, including humankind:
Survival of the Fittest
Pure, unbridled strength is one of the truest forms of this physical fitness, and humans are certainly not shy to put their brute force on display.
From simple bar room bouts of arm wrestling, to cultural festivals like the Highland Games of Scotland, to mass entertainment TV shows like American Gladiator and Sasuke (the Japanese predecessor of American Ninja Warrior), it is inherent in humans to demonstrate their physical power.