Riverboarding
（重定向自Hydrospeed）
Riverboarding is a boardsport in which the participant lies prone on their board with fins on their feet for propulsion and steering. This sport is also known as hydrospeed in Europe and as riverboarding or white-water sledging in New Zealand, depending on the type of board used. Riverboarding includes commercial, recreational and the swiftwater rescue practice of using a high-flotation riverboard, designed for buoyancy in highly aerated water.