Why the Pain, What's the Gain?

Running, jumping, lifting, pushing, stretching — our bodies are naturally built to move and work, strengthen and adapt. Yet the gym is a 20th century phenomenon and 'working out'a concept that has produced one of the world's biggest industries: fitness. An industry whose changing ideals reflect society's cultural shifts on what it means to be fit, and how to have the perfect physique.

Why the Pain?...