Mizuki Noguchi, Japanese runner

Mizuki Noguchi (野口 みずき, Noguchi Mizuki, born July 3, 1978) is a Japanese professional long-distance runner who specialises in the marathon event. She is an Olympic champion over the distance.

Initially starting out as a track and cross country athlete, her first major success was becoming the Asian cross country champion at age 21. She soon switched to road running, however, focusing on the half marathon. She won the individual and team silver medals at the 1999 IAAF World Half Marathon Championships, and won a second team silver with a fourth-place finish at the same competition in 2000.

A switch to the marathon event demonstrated her talents further: She won the Nagoya and Osaka Women's Marathons, and took the silver medal in the marathon at the 2003 World Championships in Athletics. Her good form continued and she became the Olympic champion in the marathon at the 2004 Athens Olympics. She won the Berlin Marathon the following year, setting world records at 25 km and 30 km along the way, and finishing with a personal best of 2:19:12 – a course record in Berlin and a new Asian record for the distance. The 25K world record was beaten by Mary Keitany of Kenya in 2010, who ran the distance in 1:19:53 hours.Before the 2008 Summer Olympics in Beijing, Noguchi had set the second fastest time in the world for the previous year. However, she was ruled out of all competitions after tests revealed that she had fatigue and a muscular back problem. She missed the Olympics and the entire 2009 and 2010 seasons as a result. She returned in November 2011 with a fifth-place finish at the Zevenheuvelenloop. She tried to gain a spot on the 2012 Olympic team, but her run of 2:25:33 hours left her in sixth at the Nagoya Marathon. A return to Nagoya in 2013 brought her third place with a run of 2:24:05 hours.