track bikes have employed airfoil designs on the tubes of the frame to reduce aerodynamic drag. Given the importance of aerodynamics, the riders' sitting position becomes extremely important. The riding position is similar to the road racing position, but is ultimately dependent on the frame geometry of the bicycle and the handlebars used. Handlebars on track bikes used for longer events such as the points race are similar to the drop bars found on road bicycles. However, in the sprint event the rider's position is more extreme compared with a road rider. The bars are lower and the saddle is higher and more forward. Bars are often narrower with a deeper drop. Carbon fiber bars of many shapes, as opposed to lighter alloys, are used by many riders for their higher stiffness and durability. In timed events such as the pursuit and the time trial, riders often use aerobars or 'triathlon bars' similar to those found on road time trial bicycles, allowing the rider to position the arms closer together in front of the body. This results in a more horizontal back and presents the minimum frontal area to reduce drag. Aerobars can be separate bars that are attached to time trial or bull horn bars, or they can be part of a one-piece monocoque design. Use of aerobars is permitted only in pursuit and time trial events. Formats of track cycle races are also heavily influenced by aerodynamics. If one rider closely follows, they draft or slipstream another, because the leading rider pushes air around themselves; any rider closely following has to push out less air than the lead rider and thus can travel at the same speed while expending less effort. This fact has led to a variety of racing styles that allow skilled riders or teams to exploit this tactical advantage, as well as formats that simply test strength, speed and endurance. During the early 1990s in individual pursuit events, some riders, including Graeme Obree, adopted a straight-armed Superman-like position with their arms fully extended horizontally, but this position was subsequently outlawed by the Union Cycliste Internationale (UCI), the sport's ruling body. Records In addition to regular track racing, tracks are also the venue for many speed records. These are over either a fixed distance or for a fixed period of time. Generally, time trial events (200m, 500m, 1 km, and Individual Pursuit) will be recorded for