Metrication in the United States traditional mile-based lengths. In the Olympics, athletes run 1500 meters, not 1600 meters. Running races in the U.S. are usually run in metric distances (e.g., the 100 metres dash or the 5K run), although the mile distance remains popular. But even 5 and 10 kilometer races most often have mile markers on the course, and no kilometer markers. Long-distance races are often measured in kilometers, although exceptions exist (generally 10 mile races). The marathon is referred to as a 26.219-mile race (the official marathon standard distance originally being in English units — 26 miles, 385 yards) rather than 42.195 km.
Swimming at the 2012 Summer Olympics – Women's marathon 10 kilometre water marathon at the 2012 Olympics featured a field of 25 swimmers: Swimming at the 2012 Summer Olympics – Women's marathon 10 kilometre The women's marathon swimming over a distance of 10 kilometres at the 2012 Olympic Games in London took place on 9 August in the Serpentine at Hyde Park in London, United Kingdom. Hungary's Éva Risztov ended her eight-year absence from Olympic action to capture the women's 10 km marathon title in open water swimming. Leading most of the stretch in a grueling race, she held off a late resistant surge from American teen Haley Anderson on the