BOBSLEDDING

Course used in both bobsledding and lugeing. also called bobsleighing the sport of sliding down an ice-covered natural or artificial incline on a four-runner sled, called a bobsled, bobsleigh, or bob, that carries either two or four persons. Bobsledding originated as a sport distinct from tobogganing in Switzerland about 1890, and the first organized competition was held in 1898 on the Cresta Run at St. Moritz, Switzerland. The sport earned its name after competitors adopted the technique of bobbing back and forth to increase the speed of the sled. In 1923 bobsledding became an internationally recognized sport with the organization of the International Bobsleigh and Toboggan Federation (Fdration Internationale de Bobsleigh et de Tobogganing ) and with its inclusion in the first Olympic Winter Games at Chamonix, France, the following year. Since 1931 both two-man and four-man world-championship competitions have been held yearly, except during World War II. Though several countries have women's bobsled teams, international competition is not offered for females. The bob run used in international competition is between 1,200 and 1,600 metres (1,313 and 1,750 yards) long, with an average slope of between 8 and 15 percent. There are generally from 15 to 20 turns per course, ranging in size up to huge hairpins of more than 180. Most bob runs have permanent foundations of concrete or stone, which are covered with several inches of ice. The straightaways have sidewalls of reinforced ice about 46 cm (18 inches) high. The large turns are banked very steeply, built up as high as 6 metres (20 feet), and may have an overhanging lip of ice to prevent the fast-traveling bobsleds from flying out of the turn. Early bobsleds were built mostly of wood. Steel runners were adopted within a few years, and, by the mid-20th century, steel and aluminum were used throughout. The four runners are generally mounted in pairs on two axles. Steering is accomplished by turning the front axle either with ropes or by a wheel linked to the axle by cables. The brake is a toothed bar that is pressed against the ice between the rear runners. Racing bobsleds have a streamlined cowling in front of the driver to reduce wind resistance. Two types are used: two-man boblets, as they often are called in Europe, and four-man bobsleighs. Rules limit combined team-and-sled weights to 390 kg (860 pounds) and 630 kg (1,389 pounds), respectively. Other sled dimensions are also specified. The start of the race is crucial to a team's success. Riders, wearing cleated shoes, run alongside the sled, pushing it to achieve maximum velocity. As it builds speed, the men jump in, the driver in front and the brakeman, pushing the back of the sled, entering last. The heavier four-man sleds attain speeds approaching 160 km (100 miles) per hour; the smaller, lighter two-man sleds are only slightly slower. A race consists of four descents by each team, the total time for the four heats determining the winner. Electrical timing equipment measures elapsed time to 1/100 of a second.