Sports underwear may be designed for a specific sport, or it may be designed more generically for several types of athletic activities. Generally speaking, sports underwear can be divided into two categories: lightweight summer underwear and heavier winter weight underwear. The garments may include both tops and bottoms, and the materials used to construct the underwear can vary according to the type of sport and the requirements for movement, warmth, cooling, wicking, and so on. The cost of the underwear can vary as well, especially if the underwear has special features that may require extra material.
Very often, sports underwear is designed to be breathable. This means the fabrics are moisture-wicking. Synthetic materials are often used to allow moisture to escape, keeping the skin dry and comfortable during athletic activities. In warm weather, this can prevent chafing and overheating, and in cool weather, it can prevent a drop in body temperature. Moisture wicking materials are usually lightweight synthetics that fit close to the skin, which is good for avoiding a bunching up of materials that can lead to chafing. Synthetic sports underwear does have a tendency to collect body odor quickly, however, and this may linger even after the garments have been washed numerous times.
Sometimes the sports underwear is designed for a specific sport. Baseball sliding shorts, for example, are meant to be worn as underwear, but they are also designed to protect the user from cuts and scrapes after sliding into a base. Underwear designed for males may even include a pouch in which a protective cup can be inserted for additional safety. These types of shorts are sometimes considered compression shorts because they fit tightly against the body and can even help support the muscles of the legs.
Cold weather sports require heavier weight sports underwear that are moisture-wicking for comfort and thicker for warmth. Sometimes the underwear is even designed for wind resistance; this is useful for high speed sports such as skiing. The underwear used for winter sports is full-length, meaning sleeves extend down to the wrists and pant legs down to the ankles. Natural fibers can be used for such underwear, but synthetics are usually preferred because synthetic fabrics tend to be comfortable and quick-drying. The garments can then be dried out and re-used without the need of a washer and dryer. Backpackers and mountaineers benefit from such convenience, since they are likely to be away from such amenities for extended periods of time.