Tennis players (L-R) Andy Roddick, Tomas Berdych, Novak Djokovic, Rafael Nadal, Roger Federer, Robin Soderling, Andy Murray and David Ferrer pose for a group photo ahead of the ATP World Tour Finals, in London, November 19, 2010. [Photo/Agencies]

LONDON - At 29, Roger Federer will be the elder statesman at the ATP World Tour finals which start in London's Docklands on Sunday, but the Swiss is not about to start fretting about the passing years.

In fact, the 16-time Grand Slam champion is adamant the demands of the muscular, super athletic, power-based game that now dominates tennis have made the top echelons of the game a no-go zone for the new kids on the block.

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A keen observer of the sport's trends, Federer said on Friday that there were no teenagers inside the world's top 100 and suggested you would not find a player younger than 22 with a double-digit ranking.

Just like his artistic game, which often flies in the face of the baseline warfare played by so many of his rivals, Federer's observation was spot on, as a trawl through the ATP's latest ranking list showed.

You have to scroll down to 114th-ranked Bulgarian Grigor Dimitrov - a player often compared to Federer - before you find a teenager cutting it at the sharp end of men's tennis.

It is a far cry from the day when Federer reached the top 100 when he was 18. Current world No 1 Rafael Nadal did it when he was 17 and Andy Roddick charged into the world's top 20 before his teenage years were over.

Next generation

"Promising newcomers? Not a whole lot really," Federer told reporters when asked where the next generation of possible Grand Slam champions were.

"I was asking myself that same question. It's quite surprising for me because when I was coming up there was (Lleyton) Hewitt and (Marat) Safin and Roddick and (Juan Carlos) Ferrero and (Tommy) Haas. They were all in the top 100 as teenagers.

"Then you think of Boris Becker winning Wimbledon when he was 17 and Michael Chang the French Open before that."

Rather than suggest the supply lines of talent have become snagged, Federer believes the physical demands of top-level tennis mean players are developing later, unless they are blessed with the power and athleticism of Nadal, who won 11 titles in 2005 as a teenager, including the French Open.

"It's become more physical and more mental and maybe they need longer to break through now," said Federer, the oldest of the world's top eight players contesting the season's finale at London's O2 Arena.

"It can be a good or bad thing depending on where you look at it from. But I'm always excited to see who is coming up."

Sweden's Robin Soderling, who took several years to turn his teenage potential into titles and who now, at the age of 26, has reached a high of fourth in the rankings, said tennis had become a game for grown-ups.