Line skates will have to candidly admit defeat gravity Roller pulley to a large extent derived from the skateboard. As early as 1981, athletes began to slide in the race for the skateboard ramp and U-type tube to try, they leapt to handrails, steps have been at the bottom of slide. In this way, the sport began to shape the. With the continuous popularity of the sport, who can stand the line round the block stamping high-strength also came into being. These pulleys can block the streets and in the U-shape of the ramp on the slider moves, and greatly enhance the ability to control. Nineties of the twentieth century witnessed a series of brilliant round line. 1995 Newport, Rhode Island, organized the first ESPN X Games.