On a daily basis the Roman era soldiers lived in their basically light armor, and regularly carried in the neighborhood of 60 to 70 pounds in tools, armor, and rations. They lived their whole life on foot, and striped to their fighting necessities could probably have sustained a very lively clip, even over rough terrain. Add to this the adrenalin push of the possibility of an extremely painful death, and it just might all add up.

Remember these were boys (quite literally) who had never been to Berger King.