NAIROBI, April 26 (Xinhua) -- Kenya's former 800-meter world champion Eunice Sum is set to move up the cadre this season and feature in the 1,500-meter distance starting with the Doha Diamond League meeting on May 4.

Sum, who has been struggling to return to her best form, hopes her movement up in distance will work better for her. She will launch her career this season in Doha running in the 1,500m race.

However, the 28-year-old will need to dig deep and use all her energy as she comes up against South Africa's Caster Semenya and former world junior champion Winnie Chebet in the Qatar capital.

"My training is good and I hope to start off with good results in Doha. There are no major competitions and I have rested enough since last year," Sum said Thursday in Eldoret.

Semenya was dominant at the Commonwealth Games winning both the 800m and 1,500m races.

As the 2017 world bronze medalist in 1,500m and two-time Olympic and three-time world champion in 800m, Semenya also won the 2017 Diamond League trophy over 800m following an opening victory at the Doha Diamond League last May.

Semenya closest competition will come from the two Kenyans and the 2016 world indoor bronze medalist and U-20 world indoor record holder, Gudaf Tsegay of Ethiopia.

In the men's javelin, Kenya's Julius Yego, the Olympic silver medalist will seek to put behind his loss at the Commonwealth Games by taking the game to reigning Olympic champion Thomas Rohler of Germany.

There will also be three medalists from London 2017, which includes world champion Johannes Vetter of Germany, world silver medalist and 2018 Diamond League champion, Jakub Vadlejch of the Czech Republic, and world bronze medalist Petr Frydrych of Germany.

Also in the mix are Olympic silver medalist Julius Yego of Kenya, and another rising star, 20-year-old Neeraj Chopra of India, who is the 2016 U-20 world champion, 2017 Asian champion and record-holder, and recent gold-medalist at the 2018 Commonwealth Games.

Rohler last year wowed the crowds in Doha as he threw an incredible 93.90 meters to move him to second on the world all-time list behind world record holder Jan Zelezny.

However, just two months later, the 2017 European Athlete of the Year winner Vetter overtook Rohler to claim the second world all-time position after he threw 94.44m in Luzern.

The world champion has continued this scintillating form into 2018, where he has already thrown 92.70m at the European Throwing Cup in Portugal in March.