Cold-weather warfare
Trench foot is a medical condition caused by prolonged exposure of the feet to damp, unsanitary, and cold conditions at temperatures as warm as for as few as 13 hours. Exposure to these environmental conditions causes deterioration and destruction of the capillaries and leads to morbidity of the surrounding flesh. Affected feet may become numb, affected by erythema (turning red) or cyanosis (turning blue) as a result of poor blood supply, and may begin emanating a decaying odour if the early stages of necrosis (tissue death) set in. As the condition worsens, feet may also begin to swell. Advanced trench foot often involves blisters and open sores, which lead to fungal infections. If left untreated, trench foot usually results in gangrene, which may require amputation. If trench foot is treated properly, complete recovery is normal, though it is marked by severe short-term pain when feeling returns. Trench foot affected tens of thousands of soldiers engaged in trench warfare in World War I. Keeping feet warm and dry, or at least changing into warm and dry replacement footgear, is the best way to avoid trench foot.
Foot arch stretcher
The base is generally one to two feet long and is made of a rigid material. In general, either the full base or parts of the base are covered with foam or another soft material and overlaid with fabric. This manufacturing process is used to both hold the shape of the foot arch stretcher and to provide comfort for the areas of the leg and foot that will come into contact with the base while in use. Sometimes, additional padding is added to the area of the foot stretcher base that will come into contact with the heel of the foot. This additional padding is added for comfort because the heel area usually receives the most leverage and accompanying pressure during the stretching process.