Bobsleigh or bobsled is a winter sport in which teams of two or four make timed runs down narrow, twisting, banked, iced tracks in a gravity-powered sled that are combined to calculate the final score.
Runs begin from a standing start, with the crew pushing the sled for up to 50 meters before boarding. The runners of the sled follow grooves in the ice for this distance, so steering is unnecessary until after the sleigh exits the starting area. Races can be lost in the initial push but are rarely won there. Over the rest of the course, the sleigh's speed depends on its weight, aerodynamics, runners, the condition of the ice, and the skill of the driver.
Race times are recorded in hundredths of seconds, so even seemingly minor errors can have a measurable impact on the final race standings. Because any decrease in speed affects the sleigh for the remainder of the course, errors made high on the track will have a greater effect than those made closer to the finish. Each run down the course in competition is referred to as a heat. The men's and women's standings for normal races are calculated over the aggregate of two runs or heats.