Story highlights Julius Yego is first Kenyan to qualify for a field event at the Olympics

Yego reached javelin final at 2012 London Games and finished 12th

The 23-year-old is targeting a medal at the 2013 world championships

He refined his technique by watching videos on YouTube

He is self coached, he relies on YouTube videos to hone his technique -- and in running-mad Kenya, he had to plead with officials to win selection for the track and field team as a javelin thrower.

Julius Yego may not have won a medal at the 2012 London Olympics but his achievement in just qualifying and then reaching the final in this specialist discipline was a triumph over adversity.

"I do not have a coach, my motivation comes from within. Training without a coach is not an easy thing," he told CNN's Human to Hero series.

But this obvious handicap did not prevent him hurling the 800-gram spear 81.81 meters -- his personal best, breaking his own national record -- in qualifying in London to join his sport's elite.

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Yego eventually finished 12th in the final behind Keshorn Walcott of Trinidad and Tobago, who shocked the likes of two-time defending champion Andreas Thorkildsen of Norway to win a surprise gold.

Walcott's upset victory, only the second by a non-European in Olympic javelin competition, should act as encouragement to Yego, who is not short of self belief.

"I want to be a legend and leave a legacy," he said.

"My focus now is on the 2013 World Championships in Moscow. I am trying to be in the top three. I have to move into the medal bracket, not just in the finals."

Yego had to battle "a lot of challenges" to gain acceptance in his own country as a world-class athlete.

The 23-year-old hails from a village in the Rift Valley, the traditional breeding ground for the seemingly endless stream of Kenyan distance runners who have enjoyed such success in distances from 800 meters to the marathon.

The fourth child in a family of nine, he took up the javelin at secondary school when he realized he wasn't going to be a successful footballer.

"My first-born sister used to encourage me, my mum also, but my dad sometimes was angry with me," Yego said.

"Most of my time I was going out of school, no learning, so he was a bit angry with me. But after I proved him wrong he let me continue with this sport."

Yego briefly dabbled with the track, but at a stocky 85 kg his physique is more suited to an event like the javelin and its incredible technical demands.

It helped that an elder brother was also a javelin thrower at their elementary school, and he was also inspired by watching the 2004 Athens Games on the television.

"It just took me, I wanted to be like Andreas Thorkildsen," he said.

Little could he have realized that eight years later, Yego would be competing against his hero in an Olympic final.

With no specialist javelin coaches in Kenya, the then teenager turned to technology to see what Thorkildsen and other great champions such as Czech Jan Zelezny were doing.

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"I watched YouTube and it really paid off for me, to see the training techniques and skills they are using," he said.

Yego first made his mark with third place at the 2010 African championships in Kenya's capital of Nairobi, but disappointment followed at the Commonwealth Games in New Delhi later that year as he was well below his best in finishing seventh.

His big breakthrough came in 2011 at the All-Africa Games, but he nearly did not make it to the championships in Mozambique, which were to prove pivotal to his career and eventual qualification for the 2012 Olympics.

Yego was initially told he would be going with the Kenyan team to the event, but three days later came the shattering news that he would not be making the trip.

"I rang one of the officials in our federation and I asked what was happening," he recalls.

"He told me we don't have enough cash to accommodate all of you, so I told him you can remove one of the runners so you can give me a chance!"

Yego's confrontation with officialdom clearly struck a chord, and three days later he was reinstated on the team.

He repaid their faith with a national record of 78.20m to become the first Kenyan to win javelin gold at the All-Africa Games.

It also led to an invite from the IAAF, the world governing body of track and field, to go on a six-month scholarship to its center in Kuortane, Finland, the traditional home of javelin.

Returning in the spring of 2012, Yego achieved the qualifying mark for the London Olympics and threw further than 80m for the first time later in the summer.

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Now he could not be ignored by the Kenyan selectors and his dream was about to become reality, admittedly as the only field event athlete in a 44-strong team.

"My Olympic experience is something I will never forget. I'm an Olympian now, not everyone can be Olympian," he said.

Like many top Kenyan athletes, Yego has a job with the national police force, but is allowed ample time to train between four to five hours per day, working on specialist exercises in the gym, jumps over hurdles and a throwing routine.

"Javelin requires a combination of speed, skill and power, and if you don't combine all of them, you cannot get it right," he said.

"I was born with the talent, but the skills I have had to work on."

Thorkildsen remains his reference point.

"Andreas is a unique guy, he's very skilful," Yego said. "He does some gymnastics (in training) you cannot do.

"When I watch his squats he's doing almost 200 kg and I was doing 90, so you can see it's a very big range, but now I'm doing 150.

"When I read his biography, he started training when he was just 11, so you can see he's far ahead of everybody."

Still battling the lack of specialist facilities, Yego goes it alone, spending hours every day training at the Kasarani stadium in Nairobi.

"What I love about the javelin, when you throw and you hit it right, when it's flying in the sky, you feel so nice."