The general assumption about sports, is that it's healthy to exercise for a fit and nicely-shaped -- perhaps muscular body. Such a body could be a sign of good health and is being deployed to glamourize its dominance or reproducibility in nature. But of course there is also the fashion issue and bodylanguage and several other factors to judge whether one is "in shape" or not. Tomek Pietek makes a nice conceptual piece about these subjects: With his Skin Suit he raises the question whether all that training leads to a well-designed body like nature intended... or just a strapping piece of meat.
Luckily this Muscle-Man is able to show his inner beauty as well: