Former marathon world record holder Patrick Makau of Kenya has announced his retirement from athletics and will instead focus his energies on coaching younger athletes.

Makau, 33, has lost his fight to gain fitness after persistent patella-tendon injury, forced him off training and competition since 2017. With doctors warning against him running, Makau has opted to throw in the towel.

"With the age catching up, with persistent patella-tendon injury due to which I was forced to cancel competition in 2017 for both Boston and Berlin marathons, I know this is the right time to say it is enough," Makau said Thursday in Nairobi.

The two time Berlin marathon champion is credited for reclaiming the world marathon record from the grip of Ethiopian Haile Gebreselassie in 2011 when he clocked 2:03:38 eclipsing the Ethiopian's time of 2:03:59.

Gebreselassie had beaten Paul Tergat's record of 2:04:54 set in 2004. Wilson Kipsang improved Makau's record after two years to 2:03:23, but that has also been shuttered to 2:02:57 by Kenyan Dennis Kimetto, which is the current record.

"I have had a wonderful career as an athlete. My life is defined by athletics, what I have today is because of the sport I love. Athletics has literally changed me, allowing me to grow and to make positive impact on lives of my family and our community," said Makau, the 2007 World Half Marathon champion.

"For this I am truly grateful." However, Makau will not be taking a long walk away from athletics completely.

To remain busy, he intends to help guide a new generation of young distance runners realize their dreams and develop their careers, especially from the southern part of Kenya where he comes from.

"I want to coach some athletes who have no guides. I want to continue giving back to the community," he said.

His biggest regret however is his failure to make the cut for Kenya team to the 2012 Olympics in London despite him being the world record holder at the time.

"I missed the Olympics after failing to complete at the London Marathon in 2012 because of injury. I went to London knowing I was already in the team for the Olympics. I therefore didn't push myself to finish the marathon. I had a wild card by selectors before they had a change of heart," said Makau.

Makau, who started his road running career with victory at the 2005 Zanzibar Half Marathon, believes it was the late Danish coach Zane Branson, who nurtured his talent.

However, he says his injury crisis was down to failure to embrace physiotherapy, strength and conditioning early enough during his career.

He signed up for Adidas Running team and he has been one of their top talents in the battle for dominance against Nike and Puma.

"It was a privilege to wear three-stripes and take marathon world record back to Kenya in one of the best shoes ever made," said Makau revering to his Addidas spikes.

Makau has run in over 20 marathons, he has finished at least 11 ever since he debut in Rotterdam in 2008.