Sportswear or activewear is clothing, including footwear, worn for sport or physical exercise. Sport-specific clothing is worn for most sports and physical exercise, for practical, comfort or safety reasons. Typical sport-specific garments include shorts, tracksuits, T-shirts, tennis shirts and polo shirts. Specialized garments include wet suits (for swimming, diving or surfing), ski suits (for skiing) and leotards (for gymnastics). Sports footwear include trainers. It also includes some underwear, such as the jockstrap and sports bra. Sportswear is also at times worn as casual fashion clothing. For most sports the athletes wear a combination of different items of clothing, e.g. sport shoes, pants and shirts. In some sports, protective gear may need to be worn, such as helmets or American football body armour.