Jemima Sumgong

2012 Sumgong was seventh at the highly competitive Kenyan Cross Country Championships at the start of 2012.

At the 2012 Boston Marathon, high-profile withdrawals and hot running conditions worked in her favour as the race came down to a sprint finish against Sharon Cherop, with Sumgong taking the runner-up spot two seconds behind. Sumgong tested positive for the banned substance prednisolone in her post-race anti-doping test and was given a two-year ban from competition by Athletics Kenya. However, she was cleared on appeal by the IAAF in September 2012, as the local injection which Sumgong had received was permitted under the governing body's rules. Cleared to race, Sumgong again finished behind Cherop at that year's Philadelphia Half Marathon, taking third place.

2013 Sumgong was much improved at the 2013 Rotterdam Marathon, as she won the race in a time of 2:23:27 – bettering her previous mark by over six minutes. She lowered her personal best for a second time in 2013 – to 2:20:48 – in finishing second to her training partner Rita Jeptoo at the Chicago Marathon.

2014 Sumgong finished in fourth place at the Boston Marathon in her fastest ever time of 2:20:41 (the downhill and point-to-point nature of the Boston course means that her time is not considered as a personal best). Later in the year, she finished second at the New York City Marathon, losing a close battle with compatriot Mary Keitany, whose winning margin of three seconds equalled the narrowest in race history.

2016 On 24 April, she won the London Marathon with the time of 2:22:58. The event was notable as she fell during the run, but still managed to finish ahead of the rest of the field. On 14 August 2016, she won a gold medal in the Rio Olympics with a time of 2:24:04. Sumgong's 2016 Olympic gold medal is Kenya's first gold medal in the women's Olympic marathon.

Doping case Sumgong was to defend her title at the 2017 London Marathon on April 23, but two weeks prior to the race she was suspended after testing positive for erythropoietin (EPO) in an out-of-competition test conducted by the International Association of Athletics Federations (IAAF) in Kenya, announced on April 6, 2017. She was eventually suspended for 4 years on it was announced on 7 November 2017 and her ban would start from 3 April 2017 which is when she was provisionally suspended. Her doping ban was eventually doubled to 8 years and re-started in January 2019 after it was deemed that she had lied and fabricated her medical records, ruling her out of international competitions until 2027. This was her second doping ban in 5 years after she tested positive in 2012 also.