<P> Football remained a popular sport in England throughout the ensuing centuries, but it wasn't until the emergence of The Football Association in 1863 that the sport of football emerged as an actual organized game in England . With this, the sport took off in popularity, and understandably a demand for equipment began to emerge to ensure player safety and comfort . More importantly, technological innovations during this time period played a key role in new methods and materials used for production of cleats . In the 1840s, a method of hardening rubber and stopping it from decaying, called vulcanization, was developed in both England and the United States . Vulcanized rubber is used in the production of all types of shoes, but is especially beneficial in the production of cleats, in that one of the primary purposes of football cleats is to protect the player's feet . Technology continued to improve in the coming decades, and by the 1890s studs are first used to make football cleats . The concept of spiked and studded shoes for other sports began to emerge as well in the late 19th century . In the 1890s, a British Company (now known as Reebok), developed the earliest known spiked leather running shoes . </P> <P> Cleats began to be used in the United States in the 1860s when metal spikes were first used on baseball shoes . A baseball shoe, as defined by the Dickson Baseball Dictionary (3rd Ed), is "a special type of shoe designed and worn by baseball players that features cleats for traction and a full set of laces for support ." The first official baseball shoe was invented and produced by Waldo M. Claflin, of Philadelphia in 1882 . The use of cleats gained further notoriety in the United States with the birth of American football in the early 20th century . The original football shoes were actually baseball shoes, but innovations quickly emerged . In the 1920s, detachable cleats were first introduced . As the game continued to grow, cleats had to adapt to technological advances in playing surfaces, most notably artificial turf . By the 1970s, players were wearing footwear with short, rubber cleats for use on artificial turf . </P> <P> Innovations in cleat technology continued to take place throughout the mid to late 20th century . In 1954, the first modern football boots were made by Adidas . They were lighter, had a non-leather sole, an upper portion made from kangaroo skin, and included replaceable rubber or plastic studs, which could be screwed in at different lengths . Later, in the 1990s, Adidas introduced another innovation in the form of rubber blades instead of studs, which faced different directions and allowed for better grip . Today, different types of cleats exist for different surfaces: replaceable aluminum cleats which are worn in wet dirt, firm plastic cleats which are for regular surfaces, and short, plastic or rubber cleats for very hard surfaces . </P> <P> Firm Ground cleats are defined as cleats that are made typically for use on natural surfaces such as dirt and grass . These cleats are equipped with large studs on the bottom of the shoe to assist in gripping the surface and preventing sliding and assisting in rapid directional changes . These studs are permanently attached to the cleats (i.e. they are not removable). The stud itself is often called a cleat . There are three main types of soccer cleats: round, hard ground, and bladed . Active outdoorsman and philanthropist Erik Van Till is credited as a creator of the round cleat . While the studs are sometimes made out of metal, this is less common, as they are illegal in some sports for safety reasons . </P>

What is the bottom of a cleat called