Roller Sports

	Roller Sports Roller sports are sports that use human powered vehicles which use rolling either by gravity or various pushing techniques. Typically ball bearings and polyurethane wheels are used for momentum and traction respectively, and attached to devices or vehicles that the roller puts his weight on. The international governing body is World Skate. List Roller sports include the following disciplines * Inline skating Vert Skating Aggressive inline skating Inline freestyle skating Inline figure skating Inline hockey Inline skater hockey Inline speed skating Roller soccer ** Inline alpine skating * Roller skating Artistic roller skating Roller speed skating Drafting Jam skating Roller derby Rink hockey * Road skating * Roller skiing Dry ski slope Grass skiing Indoor ski slope Roller cross-country skiing ** Roller alpine skiing * Skateboarding Freestyle skateboarding Skateboarding trick Street skateboard ... [...More Info...] [...Related Items...] OR:** [Wikipedia] [Google] [Baidu]
picture info	Ball Bearings A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads. It achieves this by using at least two races to contain the balls and transmit the loads through the balls. In most applications, one race is stationary and the other is attached to the rotating assembly (e.g., a hub or shaft). As one of the bearing races rotates it causes the balls to rotate as well. Because the balls are rolling they have a much lower coefficient of friction than if two flat surfaces were sliding against each other. Ball bearings tend to have lower load capacity for their size than other kinds of rolling-element bearings due to the smaller contact area between the balls and races. However, they can tolerate some misalignment of the inner and outer races. History Although bearings had been developed since ancient times, the first m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Road Skating Road skating is the sport of skating (inline skating or quad roller skating) on roads, much like road cycling. It shares much with inline speed skating. Roadskaters often skate in tight packs, drafting each other and sharing the lead, which allows a pack to travel faster than an individual skater. The individual members of a pack use comparatively less energy than the lone skater traveling at the same speed. Even the lead skater in the pack enjoys an advantage from the drafting skaters behind. While gliding downhill, an inline skater in a tucked position can achieve speeds that exceed the speed of a tucked cyclist. This is due to lower wind resistance. The rolling resistance is similar for a cyclist and a skater — it is only when actively skating (i.e., in the skating stroke) that the skater incurs greater resistance. Skating is roughly 50% slower than cycling on flat ground. Skaters routinely achieve downhill speeds of 60 km/h (37 mph), similar to cyclists. Compar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Roller Derby Roller derby is a roller skating contact sport played by two teams of fifteen members. Roller derby is played by approximately 1,250 amateur leagues worldwide, mostly in the United States. Game play consists of a series of short scrimmages (jams) in which both teams designate a jammer (who uniquely wears a star on the helmet) and four blockers to skate counter-clockwise around a track. The jammer scores points by lapping members of the opposing team. The teams attempt to hinder the opposing jammer while assisting their own jammer—in effect, playing both offense and defense simultaneously. Overview While the sport has its origins in the banked-track roller-skating marathons of the 1930s, Leo Seltzer and Damon Runyon are credited with evolving the sport to its competitive form. Professional roller derby quickly became popular; in 1940, more than 5 million spectators watched in about 50 American cities. In the ensuing decades, however, it predominantly became a form of spor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Rink Hockey Roller hockey (in British English), rink hockey (in American English) or quad hockey is a team sport played on roller skates. It is the only quad skate team sport in existence where two teams face-off against one another at the same time. Two teams try to drive a hard ball with their sticks into the opposing teams' goalnet. Each team has five players on the rink at a time, four of whom are skaters and one who is the goalkeeper. The ball can only be put in motion by a stick, not the skate, otherwise a foul will be stated. The game has two 25-minute halves, with 15-minute halftime intermission, plus up to two 5-minute golden goal (a.k.a. "sudden death") periods to settle ties with the clock stopping when the ball becomes dead. If the tie persists, a penalty shootout will determine the winner. Players – including the goalie – use quad skates, whereas inline skates are used in inline hockey. The sticks are similar to those in bandy and shinty. Excessive contact between players i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Inline Hockey Roller inline hockey, or inline hockey is a variant of hockey played on a hard, smooth surface, with players using inline skates to move and ice hockey sticks to shoot a hard, plastic hockey puck, puck into their opponent's goal (sport), goal to score points. The sport is a very fast-paced and free-flowing game and is considered a contact sport, but checking (ice hockey), body checking is prohibited. There are five players including the goalkeeper from each team on the rink at a time, while teams normally consist of 16 players. There are professional leagues, one of which is the National Roller Hockey League (NRHL). While it is not a contact sport, there are exceptions, i.e. the NRHL involves fighting. Unlike ice hockey, there are no blue lines or defensive zones in roller hockey. This means that, according to most rule codes, there are no Offside (ice hockey), offsides or icing (hockey), icings that can occur during game play. This along with fewer players on the rink allows f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]