There are three distinct sliding sports, performed on what would popularly be termed types of sledge, gliding at high speed, against the clock, downhill on an iced track. These are skeleton, luge and bobsleigh racing. Skeleton is always an individual sport, luge can be individual or in pairs while bobsleigh is usually for two or four persons although in para-bobsleigh a single-person monobob is used. After a running start, Skeleton riders travel head-first lying on their front on the sledge while luge is performed with the rider lying on their back, travelling feet first. Bobsleighs are easily distinguished as they are covered machines that the riders sit inside after running to push off, although monobobs may be driven by a seated athlete throughout the run. Technology is important in the sports for the aerodynamic design and materials of the sledges, athletes’ costumes, track design and refrigeration and mountain transport infrastructure. The infrastructure of the three sliding sports, skeleton, luge and bobsleigh, is expensive to maintain, especially if artificial refrigeration is used. The different disciplines, especially bobsleigh and skeleton, therefore often share the same track. In competition race results are determined by timed runs, often over a couple of days. Rules about the weight, materials, type of steel used for runners, enforced by testing procedures, also ensure fair play. The three disciplines share the same origins as a sport in the toboggan clubs and races of late nineteenth century Switzerland.