Cycling, also called bicycling or biking, is the use of bicycles for transport, recreation, exercise or sport. Persons engaged in cycling are referred to as "cyclists", "bikers", or less commonly, as "bicyclists". Apart from two-wheeled bicycles, "cycling" also includes the riding of unicycles, tricycles, quadracycles, recumbent and similar human-powered vehicles (HPVs).
Bicycles were introduced in the 19th century and now number approximately one billion worldwide. They are the principal means of transportation in many parts of the world.
Cycling is widely regarded as a very effective and efficient mode of transportation optimal for short to moderate distances.
Bicycles provide numerous benefits in comparison with motor vehicles, including the sustained physical exercise involved in cycling, easier parking, increased maneuverability, and access to both roads, bike paths and rural trails. Cycling also offers a reduced consumption of fossil fuels, less air or noise pollution, much reduced traffic congestion. These lead to less financial cost to the user as well as to society at large (negligible damage to roads, less road area required). By fitting bicycle racks on the front of buses, transit agencies can significantly increase the areas they can serve.
In ice hockey, cycling is an offensive strategy that moves the puck along the boards in the offensive zone to create a scoring chance by making defenders tired or moving them out of position.
Cycle sport is competitive physical activity using bicycles. There are several categories of bicycle racing including road bicycle racing, time trialling, cyclo-cross, mountain bike racing, track cycling, BMX, and cycle speedway. Non-racing cycling sports include artistic cycling, cycle polo, freestyle BMX and mountain bike trials. The Union Cycliste Internationale (UCI) is the world governing body for cycling and international competitive cycling events. The International Human Powered Vehicle Association is the governing body for human-powered vehicles that imposes far fewer restrictions on their design than does the UCI. The UltraMarathon Cycling Association is the governing body for many ultra-distance cycling races.
Bicycle racing is recognised as an Olympic sport. Bicycle races are popular all over the world, especially in Europe. The countries most devoted to bicycle racing include Belgium, Denmark, France, Germany, Italy, the Netherlands, Spain and Switzerland. Other countries with international standing include Australia, Luxembourg, the United Kingdom and the United States.