Nairobi, Aug 15 (IANS): Olympic javelin silver medallist Julius Yego of Kenya has vowed he will be back in his best form after a recurrent ankle injury blighted his performance at the London World Athletics Championships.

Yego failed to score in his first attempt but returned to throw 76.29 metres and 75.31 metres to bow out of the championship in last position, reports Xinhua news agency.

"I have had a bad season. My training was good, but I have not reached the peak form I desire to compete with at this level. I will be back, stronger soon," he said on Monday.

The Commonwealth Games champion, who took the world by storm in 2015 in Beijing where he claimed Kenya's first gold in the field event, was a pale shadow of himself and lost out on his World Javelin title to Johannes Vetter from Germany, whose first attempt of 89.89 metres was enough to beat the rich field at the Olympic Stadium in London on Saturday.

Yego said it was the same groin injury that almost cost him the Commonwealth Games victory in 2014 in Glasgow.

"Even though I won I was in great pain. It's the same problem that saw me withdraw from the Olympics after the third throw," said Yego, who, however, went on to win silver in Rio.

Fourth in the Moscow 2013 World Championships, the Kenyan took the world title in Beijing in 2015.

Starting off the season with an ankle injury, the groin injury took the wind out of Yego's sails but the Kenyan is adamant he will be strong enough to challenge for medals at the 2018 Commonwealth Games in Gold Coast, Australia.

"I felt some piercing pain in the groin on my right leg after the first attempt. I tried to get some good momentum in the second and third attempts but I just couldn't," said Yego.