Rowing, often called crew in the United States, is the sport of racing boats using oars. It differs from paddling sports in that rowing oars (called blades in the United Kingdom) are attached to the boat using rowlocks, while paddles are not connected to the boat. Rowing is divided into two disciplines: sculling and sweeping. In sculling, each rower (or oarsman) holds two oars, one in each hand, while in sweeping each rower holds one oar with both hands. There are several boat classes in which athletes may compete, ranging from single sculls, occupied by one person, to shells with eight rowers and a coxswain, called eights. There are a wide variety of course types and formats of racing, but most elite and championship level racing is conducted on calm water courses 2 kilometres (1.2 mi) long with several lanes marked using buoys.
Modern rowing as a competitive sport can be traced to the early 17th century when professional watermen held races (regattas) on the River Thames in London, England. Often prizes were offered by the London Guilds and Livery Companies. Amateur competition began towards the end of the 18th century with the arrival of "boat clubs" at British public schools. Similarly, clubs were formed at colleges within Oxford and Cambridge on the programme for the 1896 games, but racing did not take place due to bad weather. Male rowers have competed since the 1900 Summer Olympics. Women's rowing was added to the Olympic programme in 1976. Today, there are fourteen boat classes which race at the Olympics. In addition, the sport's governing body, the World Rowing Federation, holds the annual World Rowing Championships with twenty-two boat classes.
