Skateboarding is a competitive and recreational freestyle sport where individuals ride atop a board with four wheels and attempt to preform various tricks. Skateboarding began in the 1950’s as asphalt surfing, and originally was created by screwing metal or roller-skating wheels onto shorter surfboards. Today, most skateboards are elliptical in size, and made of wood with four rubber wheels attached to the bottom. Skateboarding competitions are considered extreme sporting competitions, and include beginning acrobatic tricks such as ollies and heel flips, as well as difficult tricks like hospital flips and 720 Gazelle Flips.