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.
Boot (torture)
A similar implement, the "foot press", consisted of a pair of horizontal iron plates slowly tightened around the bare foot by means of a crank mechanism, squeezing the foot with sufficient force to pulverize the bones. Although it was quite standard to line the lower plate with ribs to prevent the foot from popping out of the grip of the instrument as it became sweatier, a crueler variant of this device—typically encountered in Nuremberg, Germany—lined the upper plate with hundreds of sharp spikes. A version from Venice, sometimes called the "foot screw" or "toe breaker", connected the crank mechanism to a drill that slowly mutilated the foot by boring a hole through the center of the instep as the press was tightened. In the most extreme case, the press was tightened until the plates met, so grinding the foot bones to powder.