Trench foot
Trench foot can be prevented by keeping the feet clean, warm, and dry. It was also discovered in World War I that a key preventive measure was regular foot inspections; soldiers would be paired and each made responsible for the feet of the other, and they would generally apply whale oil to prevent trench foot. If left to their own devices, soldiers might neglect to take off their own boots and socks to dry their feet each day, but if it were the responsibility of another, this became less likely. Later on in the war, instances of trench foot began to decrease, probably as a result of the introduction of the aforementioned measures; of wooden duckboards to cover the muddy, wet, cold ground of the trenches; and of the increased practice of troop rotation, which kept soldiers from prolonged time at the front.
Combat boot
The 1917 Trench Boot was an adaptation of the boots American manufacturers were selling to the French and Belgian armies at the beginning of World War I. In American service, it replaced the Russet Marching Shoe. The boot was made of tanned cowhide with a half middle sole covered by a full sole. Iron plates were fixed to the heel. It was a great improvement, however it lacked waterproofing. It soon evolved into the 1918 Trench Boot, also called the Pershing Boot after General John Pershing, who oversaw its creation. The boot used heavier leather in its construction, and had several minor changes from the 1917 Boot.