Swimming at the 1968 Summer Olympics – Women's 400 metre freestyle Swimming at the 1968 Summer Olympics – Women's 400 metre freestyle The women's 400 metre freestyle event at the 1968 Olympic Games took place between 19 and 20 October. 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. Heat 1 Heat 2 Heat 3 Heat 4 Heat 5 Heat 6 Key: OR = Olympic record
Swimming pool sanitation as bench-ledges or as "stools" at in-pool bars, plunge pools, and shallow children's wading pools. Swimming pool sanitation Swimming pool sanitation is the process of ensuring healthy conditions in swimming pools, hot tubs, plunge pools, and similar recreational water venues. Proper sanitation is needed to maintain the visual clarity of water and to prevent the transmission of infectious waterborne diseases. Sanitation methods include a water filter to remove pollutants, disinfection to kill infectious microorganisms, swimmer hygiene to minimize the introduction of contaminants into pool water, and regular testing of pool water, including chlorine and pH levels. The World Health Organization