Throw the ball up, don't think and hit it as hard as possible. And eat spinach." More seriously, Krajicek added: "Actually, it's about rhythm and timing. Once you have that, you can worry about strength." Strength in abundance will be on parade at Wimbledon from tomorrow as big boomers like Greg Rusedski, Goran Ivanisevic and Mark Philippoussis - Krajicek, too - try to blow the opposition away. The big serve has always been a potent weapon on grass, but one of its more effective exponents, Roscoe Tanner, has fascinating and surprising things to say about the cannon which got him to the 1979 Wimbledon final and won the Australian Open in 1977. Tanner, now 47, was competing last week in the Mulberry Classic seniors' event at Hurlingham. Talking between his matches, he revealed himself to be a thinking man's server rather than the brute-force fellow we all took him for when he was aceing people at speeds in excess of 140 miles an hour."I had a fascination with the serve," he said "Used right, it is a huge advantage. When you serve you get to step up and start the point, so you get to think about it before you hit it, rather like a golf shot, what to do to set up the rest of the point."Not only can you hit serves of varying speeds but you can hit the two different corners or serve right at your opponent.

You don't always have to hit the big one, it can be a threat. If the other guy is burrowed in, expecting a big serve, you can hit a medium pace, or spin one in, and he misses the return. The way I look at it, them missing the return is just as good as an ace because you don't get a bonus point for making them miss it cleanly."I tried to move the ball around, as well as hitting it hard, but I wasn't going for aces. The way I was taught was to fool the guy, because if you fool him you win the point.

It's like cricket, if the bowler gives the batsman something he isn't expecting he has a good shot at a wicket."The skill is for the server to think about what he is doing. If I was serving and the other guy hit a winning return I regarded it as my fault for serving where he was looking. I could serve at 150mph to Jimmy Connors and if he knew where it was going it would come back at 155."Rusedski is the official record holder of tennis's speed serve with 149mph but Tanner says he has been timed at 153. It happened in 1976 at a tournament in Palm Springs, California. "The speed gun came in towards the end of my career and that day I was repeatedly in the 140-145 range."Afterwards, I was told somebody from an American tennis magazine sitting in the stands with a gun had clocked me at 153.