Swimming at the 1972 Summer Olympics – Men's 400 metre freestyle Swimming at the 1972 Summer Olympics – Men's 400 metre freestyle The men's 400 metre freestyle event at the 1972 Olympic Games took place September 1. This swimming event used freestyle swimming, which means that the method of the stroke is not regulated (unlike backstroke, breaststroke, and butterfly events). Nearly all swimmers use the front crawl or a variant of that stroke. Because an Olympic size swimming pool is 50 metres long, this race consisted of eight lengths of the pool. Rick DeMont of the United States originally won the gold medal in 4:00.26. Following the race, the International Olympic
Swimming pool sanitation Other filter media that have been introduced to the residential swimming pool market since 1970 include sand particles and paper type cartridge filters of 50 to filter area arranged in a tightly packed 12" diameter x 24" long (300 mm x 600 mm) accordion-like circular cartridge. These units can be 'daisy-chained' together to collectively filter almost any size home pool. The cartridges are typically cleaned by removal from the filter body and hosing-off down a sewer connection. They are popular where backwashed water from a sand filter is not allowed to be discharged or goes into the aquifer. Automated pool