By Mitch Phillips

RIO DE JANEIRO (Reuters) - When you have become the world and Olympic champion in triple jump, arguably the most technically challenging of all athletics events, it seems a radical move to change your take-off leg, but for American Christian Taylor the switch is paying dividends.

Taylor won the world tile in South Korea in 2011, added the indoor world title in 2012 and completed a dream year when he triumphed at the London Olympics.

However, although he was still only 22, the relentless pounding had already taken its toll on his body, particularly his left knee, and he decided to take the risk of switching.

Now he lines up as favorite to retain his title, jumping further than ever, after going back to the drawing board.

"I was having a lot of patella issues with left knee," he told reporters on Wednesday. "It got to where I was focusing on coming out of competitions healthy instead of trying to strive for a world record."

So Taylor decided to switch things round, and of course initially had to go backwards to go forwards.

"It was far from easy. The biggest thing was the timing, so it was repetition, repetition," he said.

"It's a lot co-ordination. Timing and muscle development goes into it and in the 2013 world championships I didn't make the podium."

Gradually, however, things started to come together and after a "fun 2014" when he returned to the track to run some relays - including a 45.17 400 meters, he had mastered the new approach.

By the 2015 season he was not only jumping as well off his right as during his left-legged peak, but further, and in his first event he cleared 18 meters (59 ft) for the first time.

At the world championships later that year he improved to 18.21, second only to the world record of 18.29 set by Briton Jonathan Edwards in 2005, to claim his second world title.

"That 2015 was a game-changing year for me," Taylor said.

"There was incredible competition from (Cuban) Pedro Pichardo, he jumped 18 meters and he pushed me to raise my game."

Now he is in Rio seeking to become the first man since Viktor Saneyev completed his hat-trick for the USSR in 1976 to successfully defend the title.

"Triple jump is very special and to do back-to-back is very difficult," he said.

"It beats your body up and the biggest challenge is staying healthy."

Taylor, now based in the Netherlands after a spell in Britain, is injury-free at the moment and is targeting not only a second gold, but Edwards' world record.

"It's stood for so long because it was so special," he said of that remarkable leap in Gothenburg, Sweden 21 years ago.

"But trying to beat it and the excitement of the big championships is what excites me and my fire and passion is unchanged."

(Editing by Bill Rigby)