Inline skating

Inline skating is a multi-disciplinary sport and can refer to a number of activities practiced using inline skates. Inline skates typically have two to five polyurethane wheels depending on the style of practice, arranged in a single line by a metal or plastic frame on the underside of a boot. The in-line design allows for greater speed and maneuverability than traditional (or "quad") roller skates. Following this basic design principle, inline skates can be modified to varying degrees to accommodate niche disciplines.

Inline skating is commonly referred to as rollerblading, or just blading, due to the popular brand of inline skates, Rollerblade.

An inline skate appeared in a Paris patent in 1819, but were overtaken in popularity by quad skates.

The German branch of SKF developed and produced inline skates in 1978 with wheels designed for hockey rinks and streets. The product was discontinued after one year as the management did not want a consumer product in its portfolio.

Other inline skates were developed as a substitute for ice skates. In 1980, a group of ice hockey players in Minneapolis, Minnesota, were looking for a way to practice during the summer. Scott and Brennan Olson formed the company Rollerblade, Inc., to sell skates with four polyurethane wheels arranged in a straight line on the bottom of a padded boot. They sold the company in 1984 to Bob Naegele jr., who advertised to the general public and sold millions. Life magazine published a photo of American skater Eric Heiden, training for the 1980 Olympics, using such skates on a Wisconsin road.

The sport became popular in the United States in the 1980s and 1990s, with tens of millions of participants. In 1996, Jason Lewis completed the first solo crossing of the United States on inline skates, part of Expedition 360, a successful attempt to circumnavigate the globe using only human power. En route he was hit by a car in Colorado, breaking both legs. After nine months he completed the journey from Fort Lauderdale to San Francisco. In 2012, Kacie Fischer became the first woman, and the fastest person, to inline skate across the United States; she skated from California to Florida in 47 days. Aggressive inline skating events were featured in the X Games from 1995 to 2005. Popularity waned in the 2000s, with parental concerns over injuries and the rising popularity of soccer, lacrosse, and skateboarding. There was a revival sparked by the need for socially distanced recreation during the COVID-19 pandemic.

Some disciplines are part of World Games.

Aggressive inline skating (referred to by participants as rollerblading, blading, skating or rolling) is a sub-discipline primarily focused on the execution of tricks in the action sports canon. Aggressive inline skates are specially modified to accommodate grinds and the jumping of large gaps.Aggressive skates are identifiable by a prominent gap in between the second and third wheels (known as the H-block) which allows for grinds perpendicular to the direction of the wheels. A hard plastic surface on the sole of the boot known as a "sole plate" or "soul plate" allows for grinds parallel to the wheels. From these grind surfaces comes a lexicon of well-known grind stances, though sliding can occur on any surface of the boot or wheels. Aggressive skates typically have much smaller wheels than regular inline skates. The small size allows for more freedom when grinding as there is less risk of catching on obstacles. These smaller wheels feature a flat profile to accommodate the impact from jumping tall heights.