Dirt Jumping(DJ) is one of the names given to the practice of riding bikes over shaped mounds of dirt or soil and becoming airborne. The idea is that after riding over the take off the rider will become airborne, and aim to land on the landing. Dirt jumping can be done on almost anything but the bikes are generally smaller and more maneuverable hardtails so that tricks e.g. backflips, are easier to complete. The bikes are simpler so that when a crash occurs there are fewer components to break or cause the rider injury. Bikes are typically built from sturdier materials such as steel to handle repeated heavy impacts of crashes and bails.