A bronze Greek made around 450-40 BCE was made precisely to illustrate the ideal balanced form of a body. The musculature is overwhelming and certainly enhanced, and the spear balances the sculpture while silently praising the military prowess of its bearer. The figure displays a fluidness in his movement due to his contrapossto stance. One can almost see the follow-through of the behind leg.
The marble version aka the copied made by the Romans relied on a tree stump to support the weight of the stone and stay true to the athletic form and relaxed stance.