A new discovery by scientists: Neanderthals carried heavy loads more easily with flat soles A new study shows that the flat soles of the Neanderthals were not a physical defect, but an evolutionary adaptation to maintain balance and carry pressure while carrying heavy loads. The heel bone of Neanderthals was shorter, wider and longer compared to modern humans. Also, their feet were usually in a position of pronation (turning the foot inward) and the outer longitudinal arch of the foot was less high. These differences in the leg structure of Neanderthals and intelligent humans provide new information about the way our ancestors moved and the influence of lifestyle on the human skeleton.