FoolishOwl writes "Scientists at the University of Leeds tested the effects of wearing heavy medieval armor by monitoring volunteers, who were experienced medieval reenactors, as they walked and ran on treadmills, while wearing accurate replicas of 15th century armor. While the suits of armor weighed between 30 and 50 kg, comparable to the weight of gear carried by modern soldiers, volunteers who carried equivalent amounts of weight in backpacks had an easier time with the weight. Volunteers in armor burned more energy and had difficulty breathing. The scientists speculate that much of the additional effort was due to weight of armor on the legs — leg armor was one of the first things dropped in the shift towards lighter armor in the 16th century. While it has long been assumed that heavy medieval armor limited mobility, and that this contributed to the outcome of battles, such as the Battle of Agincourt in 1415, this was the first study to quantify the impact of wearing heavy armor."