Byline: Richard Evans

Agony, to be honest,' says Great Britain's Davis Cup captain, John Lloyd, when asked about the operation he has just undergone on a chronically damaged knee. 'I couldn't sleep for three weeks with the pain. Sometimes I was throwing up it was so bad.'

Jaime Fillol, the former Chilean No1, went through the same torment. 'It's fine now, but for six weeks I didn't get much sleep, it hurt so much.'

Both these players competed at a time when the game was nothing like as physical as it is today. 'Given my own experience, I dread to think what some of today's players are going to have to go through,' Lloyd says. 'The pounding their bodies take, with all the jarring and wrenching of knee joints, ankles and hips is pretty horrific, especially on hard courts. They are the worst.'

John Alexander, the former Australian Davis Cup player who used to share a BBC commentary box with Lloyd, goes further. 'Hard courts should have a health warning painted behind the baseline, just like a cigarette packet, saying, "This court serious damages your health",' Alexander says. 'If the ATP are not careful, this generation of players will end up suing them in about 10 years when their bodies collapse.'

Gary Lewin, the top physio who has just left Arsenal to join England full time, told me that he felt tennis was now one of the most physically demanding games in the world. 'It's the constant stop-start nature of how they jam on the brakes and push off in a rally that puts extreme strain on...