Cycling, also, when on a two-wheeled bicycle, called bicycling or biking

Plan

1. 
   Cycling
   
2. 
   History
   
3. 
   Equipment
   
4. 
   Racing
   
5. 
   Health effects
   
6. 
   References
   

Cycling, also, when on a two-wheeled bicycle, called bicycling or biking, is the use of cycles for transport, recreation, exercise or sport. People engaged in cycling are referred to as "cyclists", "bicyclists", or "bikers". Apart from two-wheeled bicycles, "cycling" also includes the riding of unicycles, tricycles, quadricycles, 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, especially in densely populated European cities.
Cycling is widely regarded as an effective and efficient mode of transportation optimal for short to moderate distances.
Bicycles provide numerous possible benefits in comparison with motor vehicles, including the sustained physical exercise involved in cycling, easier parking, increased maneuverability, and access to roads, bike paths and rural trails. Cycling also offers a reduced consumption of fossil fuels, less air and noise pollution, reduced greenhouse gas emissions, and greatly reduced traffic congestion. These have a lower financial cost for users as well as for 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 addition, cycling provides a variety of health benefits and reduces the risk of cancers, heart disease, and diabetes that are prevalent in sedentary lifestyles.Cycling on stationary bikes have also been used as part of rehabilitation for lower limb injuries, particularly after hip surgery.Individuals who cycle regularly have also reported mental health improvements, including less perceived stress and better vitality.
Among the disadvantages of cycling are the requirement of bicycles (excepting tricycles or quadricycles) for the rider to have certain level of basic skill in order to remain upright, the reduced protection in crashes in comparison to motor vehicles, often longer travel time (except in densely populated areas), vulnerability to weather conditions, difficulty in transporting passengers, and the fact that a basic level of fitness is required for cycling moderate to long distances.
History
Cycling quickly became an activity after bicycles were introduced in the 19th century. Today, over 50 percent of the human population knows how to ride a bike.
War
The bicycle has been used as a method of reconnaissance as well as transporting soldiers and supplies to combat zones. In this it has taken over many of the functions of horses in warfare. In the Second Boer War, both sides used bicycles for scouting. In World War I, France, Germany, Australia and New Zealand used bicycles to move troops. In its 1937 invasion of China, Japan employed some 50,000 bicycle troops, and similar forces were instrumental in Japan's march or "roll" through Malaya in World War II. Germany used bicycles again in World War II, while the British employed airborne "Cycle-commandos" with folding bikes.
In the Vietnam War, communist forces used bicycles extensively as cargo carriers along the Ho Chi Minh Trail.
The last country known to maintain a regiment of bicycle troops was Switzerland, which disbanded its last unit in 2003.
Equipment
In many countries, the most commonly used vehicle for road transport is a utility bicycle. These have frames with relaxed geometry, protecting the rider from shocks of the road and easing steering at low speeds. Utility bicycles tend to be equipped with accessories such as mudguards, pannier racks and lights, which extends their usefulness on a daily basis. Since the bicycle is so effective as a means of transportation, various companies have developed methods of carrying anything from the weekly shop to children on bicycles. Certain countries rely heavily on bicycles and their culture has developed around the bicycle as a primary form of transport. In Europe, Denmark and the Netherlands have the most bicycles per capita and most often use bicycles for everyday transport.
Road bikes tend to have a more upright shape and a shorter wheelbase, which make the bike more mobile but harder to ride slowly. The design, coupled with low or dropped handlebars, requires the rider to bend forward more, making use of stronger muscles (particularly the gluteus maximus) and reducing air resistance at high speed.
The price of a new bicycle can range from US$50 to more than US$20,000 (the highest priced bike in the world is the custom Madone by Damien Hirst, sold at US$500,000 depending on quality, type and weight (the most exotic road bicycles can weigh as little as 3.2 kg (7 lb)^]). However, UCI regulations stipulate a legal race bike cannot weigh less than 6.8 kg (14.99 lbs). Being measured for a bike and taking it for a test ride are recommended before buying.
The drivetrain components of the bike should also be considered. A middle grade dérailleur is sufficient for a beginner, although many utility bikes are equipped with hub gears. If the rider plans a significant amount of hillclimbing, a triple-chainrings crankset gear system may be preferred. Otherwise, the relatively lighter, simpler, and less expensive double chainring is preferred, even on high-end race bikes. Much simpler fixed wheel bikes are also available.
Many road bikes, along with mountain bikes, include clipless pedals to which special shoes attach, via a cleat, enabling the rider to pull on the pedals as well as push. Other possible accessories for the bicycle include front and rear lights, bells or horns, child carrying seats, cycling computers with GPS, locks, bar tape, fenders (mud-guards), baggage racks, baggage carriers and pannier bags, water bottles and bottle cages.
For basic maintenance and repairs cyclists can carry a pump (or a CO₂ cartridge), a puncture repair kit, a spare inner tube, and tire levers and a set of allen keys. Cycling can be more efficient and comfortable with special shoes, gloves, and shorts. In wet weather, riding can be more tolerable with waterproof clothes, such as cape, jacket, trousers (pants) and overshoes and high-visibility clothing is advisable to reduce the risk from motor vehicle users.
Items legally required in some jurisdictions, or voluntarily adopted for safety reasons, include bicycle helmets, generator or battery operated lights, reflectors, and audible signalling devices such as a bell or horn. Extras include studded tires and a bicycle computer.

Bikes can also be heavily customized, with different seat designs and handle bars, for example.