By Amy Tennery
NEW YORK (Reuters) - When Milos Raonic steps out for a match, he usually expects to be the tallest player on court.
Except at the U.S. Open on Sunday, the 6-foot-5 inch Canadian found himself face-to-face -- or, more accurately, face-to-chest -- with man mountain John Isner, who stands five inches taller.
The sight of towering men taking only a couple of strides to run in from the baseline to the net is nothing new at the majors, with 6-foot-8 Kevin Anderson finishing runner-up at Flushing Meadows 12 months ago and again at Wimbledon in July.
Yet before 2007, there were no men ranked in the top 50 who were taller than two metres (6 foot 6), according to the International Tennis Federation (ITF) -- today, five of the world's top 11 men breach the 6-foot-5 mark.
As these tennis skyscrapers start getting deeper into the slams, they impact how the game is played, according to experts and professionals alike, with the serve being the most obvious weapon at the disposal of the sport's new breed of giants.
Isner's coach David Macpherson said taller players can have "a massive advantage" with their serve.
"You can create more angle in the box, you can get the ball shorter and wider in the box than other players, clear the net by greater margins, and get the ball to bounce higher," Macpherson said.
Players above 1.98 metres (6 foot 6) served at least one ace for every 10 serves, according to the ITF's most recent State of the Game data obtained from the Fed Cup, Davis Cup and Grand Slams. Men who are 1.82m (6 foot) and under recorded just one ace for every 20 serves.
Yet it is not just the ace count that explains why so many tall players are climbing the rankings.
'GREATER LEVERAGE'
Mark Kovacs, executive director of the International Tennis Performance Association, told Reuters that tall players cover more ground with longer strides and generate greater power from groundstrokes, impacting how the sport is played.
"With more tall players the style of play is shifting slightly due to the greater leverage these players have," Kovacs said.
"The more the height increases (among players) the more likelihood we will see more players coming to the net more due to how difficult it is to pass a tall player. That will likely be a change over the next decade," Kovacs said.
ITF data from the Davis Cup also shows that taller players are pushing out the marathon rallies of the sport's past.
When the tallest 25 percent of players serve, 57 percent of their rallies are four or fewer shots. This figure is 10 percent greater than for the shortest 25 percent.
The last time any man shorter than 6 feet won a Grand Slam was almost 15 years ago, an honour that 2004 French Open champion Gaston Gaudio may hold forever.
ADVERTISEMENTWhereas the sport's towering giants were renowned in the past for their huge serves and not much else, former U.S. Open champions Juan Martin del Potro and Marin Cilic, who currently share the record of being the tallest-ever Grand Slam winners at 6 foot 6, have proved to be far from one-trick ponies.
Backing up his booming serve with swift court coverage and canny shot selection, Del Potro squashed Borna Coric in straight sets to clinch his quarter-final berth on Sunday.
With an increasing number of tall players including Del Potro, Alexander Zverev, Anderson, Cilic and Isner, it is not inconceivable that in another 20 years, players such as Roger Federer and Rafael Nadal, who are both 6 feet 1, might be considered an anomaly in the sport rather than the norm.
German fourth seed Zverev, 6 foot 6 and tipped by many as a future grand slam champion, fired down a 136 mph missile during his third-round defeat by Philipp Kohlschreiber.
"I think tennis is going towards the direction of powerful, hard hitters, and that's what us tall people are," the 21-year-old Zverev told reporters.
ADVERTISEMENT(Reporting By Amy Tennery, editing by Pritha Sarkar and Toby Davis)