The spandex speed suits worn by downhill ski racers generally provide minimal protection from high winds, and almost no protection from cold air and crashes while racing. Most racers wear skin-tight thermal underwear underneath the suits and don thicker ski jackets and tearaway pants between runs.
The Olympics and international racing associations mandate that all downhill ski suits worn in competition be at least minimally air-permeable. Because of this requirement, alpine racing suits offer only mild protection from the biting winds and rushing air that racers may encounter. With many races decided by 10ths of seconds, most racers prefer to sacrifice personal comfort for the improved aerodynamics accorded by these sleek alpine speed suits. Some downhill racers do wear a body-shaped plastic protection device on their backs underneath their suits, but otherwise race with no other padding or protections within the suit itself.
Many racers attempt to mitigate the elements by wearing thin, micro-fiber thermal underwear underneath their suits. This provides increased protection from the cold air that seeps in through the permeable outer material. For further protection, it is common to see racers wear thicker ski jackets and insulated pants with full length zippers over their suits while they await their runs.
An experimental suit was approved for international competitions in late 2015. It uses accelerometers and smart technology to automatically inflate, providing more protection from the elements than traditional alpine racing suits.