LONDON, Aug. 27 (Xinhua) -- Following is an A-Z of swimming at the London 2012 Paralympic Games, which will officially open on Aug. 29:
Anchor - The final swimmer in a relay event.
Backstroke, breaststroke, butterfly - Three of the four competitive racing strokes at the London 2012 Paralympic Games. Freestyle is the other stroke.
Classes - There are 10 classes for swimmers with a physical impairment. Class 1 swimmers have an impairment which affects their swimming of a stroke the most. Class 10 swimmers have an impairment which affects their swimming of a stroke the least. There are three classes for swimmers with a visual impairment (11 to 13) and class 14 is for swimmers with an intellectual impairment (learning disability).
Drafting - To swim just behind another competitor in an adjacent lane to take advantage of the watery slipstream created by his or her wake.
Events - The shortest Paralympic swimming event is 50m - one length of the pool. The longest event is 400m - eight lengths of the pool.
Freestyle - An event in which swimmers may use any stroke they choose, usually the crawl. In the medley events, freestyle means any stroke other than backstroke, breaststroke and butterfly.
Gold - There will be 148 gold medals contested at London 2012. There are 67 events for women and 81 events for men.
Heats - All swimmers race in groups of up to eight at a time. The top eight qualifiers from the heats go through to the finals.
IPC - International Paralympic Committee - the governing body of sports for athletes with a disability.
INFO - The place media go for all the Paralympic sport news, flash quotes, results, biographies and much more.
Jessica - Jessica Long from the United States was born in Siberia, Russia. She was adopted from a Russian orphanage at the age of 13 months and moved to the USA. LONG won three golds at the Paralympic Games at Athens 2004 and four golds, one silver and one bronze at Beijing 2008.
Kick - The leg movements of a swimmer. From February 2011, a breaststroke kicking movement is no longer permitted in butterfly.
Ludwig - German-born neurologist Sir Ludwig Guttmann (3 July 1899 - 18 March 1980) founded the Paralympic Games precursor, the Stoke Mandeville Games, in 1948 while working with injured military personnel at the national spinal injuries centre at Stoke Mandeville Hospital in Buckinghamshire. He is considered one of the founding fathers of organized physical activity for people with a disability. His daughter Eva Loeffler from Britain has been appointed mayor of the London 2012 Paralympic Village.
Medley - A relay event in which each competitor in a team swims separate legs of each of the four racing strokes. The order of strokes is backstroke, breaststroke, butterfly and freestyle. In the 150m medley races, swimmers use only three strokes. They do not swim butterfly.
Negative split - Swimming the second half of the race faster than the first half.
Oldest - The oldest swimmer competing at London 2012 is 55-year-old Sebastian Rodriguez from Spain, born Feb. 27, 1957.
Paralympic swimming - is one of the few sports to have taken place at every Paralympic Games since Rome 1960.
Qing - Xu Qing from China won four medals at Beijing 2008, including three golds.
Relay - In relay events each team has four swimmers. Each swimmer must not start until the swimmer in the pool has touched the finishing pad.
Swimmers - Paralympic swimmers can start their race in different ways. They can stand atop or beside the starting block, start from a sitting position, in the water or have help with balance while on the starting block.
Tap - Visually impaired swimmers have someone who uses a pole to tap them when they are reaching the end of the pool.
Underwater - There are seven underwater camera viewing windows at the Aquatics Center.
Visual - Visually impaired swimmers wear blackened goggles to ensure the same level of blindness.
Wings - The two temporary wings at the Aquatics Center will be removed after the London 2012 Paralympic Games, reducing its spectator seating capacity from 17,500 to 2,500.
Xavier - Xavier Torres, from Spain, has won 16 Paralympic medals in swimming since his debut at Barcelona 1992.
Youngest - The youngest swimmer competing at London 2012 is 13-year-old Nikita Howarth from New Zealand, born 24 December, 1998.
Zaha Hadid - The internationally acclaimed British architect and designer of the Aquatics Center.