Competitive rowing includes many different types of competition, e. g. endurance races, time trials, stake racing, bumps racing and side-by-side formats. There are two types of rowing: In sweep rowing, each rower has one oar, held with both hands. Whereas in sculling each rower has two oars, one in each hand, usually without a coxswain. The standard competition distance for world rowing championship side by side races is 2 km.