Skateboard legend Tony Hawk is considered one of the world's greatest skateboarders, the only skateboarding guru who successfully completed the front side "900." This stunt consists of 2.5 midair somersaults (900 degrees of breathtaking action) and was witnessed at the ESPN X Games in San Francisco, California in 1999. Since then, daredevils and skating enthusiasts of all ages and skill levels have attempted to replicate the amazing act, but few have managed to pull off the stunt as flawlessly as the great Hawk.

The 900 was executed when Hawk launched approximately 5 feet from the rim of the half-pipe on the U-shaped skate ramp and then did two and a half flips on the board before landing back into the half pipe with both feet and the board intact. For Hawk, it was one of his greatest personal achievements; for spectators, this was history in the making. And for scientists, it was just another trick made possible by the laws of gravity.

Skateboard stunts like the 900 depend entirely on the laws of physics; gravity allows the skater to accelerate, control their speed, move at different angles while airborne and control exactly where they will land. The faster the skater moves, the higher they can launch themselves above the rim of the skateboard ramp. The best way to pick up speed on the ramps is to use a technique called 'pumping,' where the skateboarder uses one foot to launch forward on the board and then quickly bends his or her knees while moving in order to accelerate. After launching off the rim, the skateboarder must curl up into a tight ball so that their body weight is as close to their axis of rotation as possible. This may sound very technical and complicated, but it's the blueprint for skateboarding stunt success for many experienced skaters such as Hawk.

Skateboarders also need to consider wind speed and temperatures when they're approaching a new stunt; the wind can affect how quickly the skateboarder is able to accelerate when on the ground and how long they can be airborne. The climate dictates what type of clothing the skateboarder will need to wear and whether the skateboard's wheels need to be warmed up before the event.

Hawk's execution of this amazing 900 stunt is just one of several legendary tricks and stunts to make headlines in the skateboarding world; he officially retired from professional skating in 2000.

Source:

Science World, Feb. 2001