From Longman Dictionary of Contemporary Englishbackstrokeback‧stroke /ˈbækstrəʊk $ -stroʊk/ noun [singular, uncountable] DSSa way of swimming on your back by moving first one arm then the other backwards while kicking your feet
Examples from the Corpus
backstroke• Rouse owned the 100 backstroke, owned the world record.• A similar best ever 2.57.68 saw Jonathan Sayer fourth in the 200 backstroke.• She made the Olympic team last week, then finished second in the 200 backstroke on Monday.• Susan is in nine events 100m and 200m backstroke, breaststroke, butterfly, freestyle and 200m individual medley.• That would be Counsilman, who plans to swim the 50 backstroke and 50 freestyle.• Then I slipped over and did a leisurely backstroke back up the pool.• Martin won the 13 years 100 metre backstroke by one hundredth of a second.• In the water he started out on a fast crawl, then switched to a slower backstroke.