Naturalism in Greek sculptures, in part, was the result of what medical practices?
The natural beauty of the human body became prevalent during the Archaic period. Sculptures during this period tended to be nude males (females of the period were clothed). The male sculptures were posed standing.
The Archaic period influenced (and became) the Classical period. Sculpture of this period became more realistic (naturalistic) because of the new studies of human movement and anatomy. The main pose of both the Archaic and Classical period was Contrapposto. In this pose, the figure is standing with weight shifted more towards one foot. This would then shift the shoulders into a more natural and realistic pose.