Just four years ago, Eunice Sum was a heptathlete living in a Kenyan village. Now, she is the dominant force in the women’s 800m, and will spearhead Kenya's medal charge at the World Relays later this month alongside her mentor and track 'mother' Janeth Jepkosgei.

It is hard to believe now, but world champion Eunice Sum once regarded the 800m as a “tough event” – one she didn’t think she was suited to.

Just like Kenya’s 800m world record holder David Rudisha, Sum was a schoolgirl multi-eventer. The two-lap event represented the painstaking finale to the gruelling seven-discipline heptathlon. 

“I never had the endurance for the 800m,” the softly-spoken 25-year-old tells SPIKES.

It was Janeth Jepkosgei (2007 world 800m champion) who first recognised Sum’s potential. After watching a 21-year-old Sum produce a 2:27 800m in the heptathlon at a meeting in Kenya in September 2009, Jepkosgei asked her if she would like a job in the police force, and the opportunity to train with her group in Eldoret.

“It was a big honour and I accepted immediately. Janeth was a world champion from Osaka [2007]. I was pleased to be given the chance to train in athletics, and also be recruited for the police.”

Sum, who was good enough in the heptathlon to finish second at the national junior championships, left the sanctuary of her home village to live and train in Eldoret.

“The first week, I couldn’t even keep up with the runners for the first 20 minutes. After just ten minutes I was dying,” she says. “But Janeth used to encourage me to catch up. Slowly I improved and could keep up for longer.”

Sum – whose cousin Alfred Kirwa Yego won world 800m gold at the same champs as Jepkosgei – gradually became accustomed with the specific training demands of the 800m. In 2010, her first full international season, she ran a time of 2:00.28 in Slovenia. 

She dipped below the two-minute barrier for the first time with 1:59.66 for second at the 2011 Kenyan champs. She also reached the semi-finals of the world championships in Daegu, missing out on the final by just one place. She describes her display in South Korea as a “great moment”.

Eunice Sum in the 800m at the IAAF World Championships (Getty Images)

Kenya in Moscow: Eunice Sum at the world champs. 

Under the advice of her coach, Claudio Berardelli, Sum opted to target the 1500m in 2012. The switch in emphasis seemed to work when she finished second over the metric mile distance at the Kenyan Olympic trials.

A personal best of 4:04.26 in Paris three weeks before the Olympics offered further encouragement, but at London 2012 she wound up tenth in her heat, recording a modest 4:16.95.

“To this day, I really don’t know what happened,” she says. “The night after the race I couldn’t even sleep.”

Such disappointment, in an Olympic Stadium just 10 miles (16km) away from the home of her beloved Chelsea Football Club, was hard to take. Counselled by her family, Sum recalls her cousin Yego telling her: “When things happen, you just have to accept them”.

She did more than just accept it. Racing sparingly over 800m, she used the 1500m as an endurance builder in the countdown to the Moscow 2013 World Championships.

Approaching Moscow under the radar (bar an early season PB of 4:02.05 for the 1500m in Doha), Sum had a ‘round-by-round’ mentality and made the final along with Mariya Savinova, the Russian world and Olympic champion.

“I hoped to compete for a medal, because Savinova was at home,” says Sum.

In that final, the rangy athlete executed a perfect race of controlled aggression to slay the home favourite. 

Second at the bell but eight metres adrift of the leader Alysia Montano, Sum hit the home straight still down on the Montano, and facing a new threat. 

“I heard the crowd roar and then Savinova coming up on the outside. I could see by looking up on the big screen that Savinova was really moving.” 

However, with Montano fading, Savinova’s challenge started to falter – and it was Sum who slowly opened up an advantage.

“In the last 30 metres I thought I could win the gold” – and she did.

Since her magical Moscow moment, she has used her winnings to help build a new three-bedroom house in Eldoret, which will be completed later this year. 

Sum has also enjoyed the benefit of a good winter’s training, and started the season unbeaten with a couple of 800m races in Australia and a victory over the two-lap distance in Kenya. 

A 1:57.38 personal best clocked when striking world gold in Moscow is impressive enough, but it could be due for further revision this season.

“I’m stronger [than last year],” she says. “I have no injuries. Training is a little bit improved from last year.”

Sum is in the Kenyan 4x800m squad for the World Relays in Nassau later this month, and will compete alongside her mentor Jepkosgei.

“What makes this special is that I shall be in the same team with my mother in athletics, as we try our best to bring glory to our country,” says Sum.

She owes a huge debt of gratitude to Jepkosgei, for the faith she showed in her ability. Yet there is one area where the pair will never see eye to eye: English football.

“I’m a Chelsea fan, and Janeth supports Liverpool,” says Sum. “When we discuss the Chelsea v Liverpool game, there is a very big tension.”

And Sum’s having it all her own way this year. After Chelsea prevented Liverpool from winning their first league title since 1990, she romped to victory over a talented field at the season opening Diamond League meet in Doha.

Sum gets all the luck, eh?