Swimming at the 1948 Summer Olympics – Men's 400 metre freestyle Swimming at the 1948 Summer Olympics – Men's 400 metre freestyle The men's 400 metre freestyle event at the 1948 Olympic Games took place between 31 July and 4 August at the Empire Pool. 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. Key: OR = Olympic record, Q = qualification by place in heat,
Swimming pool long and at least deep. Competition pools are generally indoors and heated to enable their use all year round, and to more easily comply with the regulations regarding temperature, lighting, and automatic officiating equipment. An Olympic-size swimming pool (first used at the 1924 Olympics) is a pool that meets FINA's additional standards for the Olympic Games and for world championship events. It must be wide, divided into eight lanes of each, plus two areas of at each side of the pool. Depth must be at least . The water must be kept at and the lighting level at greater than