Heat sickness, sore, stretched muscles and chest infections.
This year's Sydney International has been the scene of more pullouts than good passing shots.
Third-seeded Elena Dementieva of Russia withdrew from her singles semifinal with heat illness on Friday, giving Australian Samantha Stosur her second walkover win in a row.
On Thursday, top-seeded Lindsay Davenport, suffering from bronchitis, pulled out of her quarterfinal with Stosur.
"Certainly having one walkover is a bit strange, but having two, it's a bit ridiculous," said Stosur.
Davenport was one of five players who withdrew or quit during matches on Thursday, the same day that Andre Agassi suffered a hip injury in Melbourne at the Kooyong exhibition tournament. His place in next week's Australian Open is in doubt.
Max Mirnyi of Belarus, a semifinal loser to Lleyton Hewitt on Friday, joined Stosur in the walkover sweepstakes at Sydney. He won his second-round match when Joachim Johannson retired with a hamstring injury and his quarterfinal when American Taylor Dent quit with dizziness.
Nadia Petrova of Russia also pulled out with heat exhaustion and Leander Paes of India, who plans to play mixed doubles with Martina Navratilova at next week's Australian Open, left a doubles match on crutches with a left foot injury.
It's been hot in Sydney over the past few days, but no hotter than usual this time of year during the height of the Southern Hemisphere summer.
Temperatures on the center court surface at the Olympic complex ranged from 40? C to 45? C on Friday, about 10 degrees warmer than the air temperature. Those are conditions similar to what the players can expect in Melbourne at the Australian Open.
The WTA Tour invoked its Extreme Heat policy on a number of occasions this week. It allows players a 10-minute break before the start of a third set if the so-called heat stress index, a combination of the ambient air temperature and court surface temperature, exceeds 28? C.
Hewitt, who prides himself on his conditioning and ability to play in all weather conditions, says the heat and the tournament's proximity to the Australian Open has a lot to do with the injuries and retirements.
"It's tough for them when they have to come over from Europe where it's minus degrees over there at the moment," said Hewitt. "So to come and expect to play your best tennis straight off the bat under these conditions, you know it's never going to happen."
Hewitt said the surface at Sydney and at Melbourne adds to the heat problem.
"I think the difference here in Australia is the Rebound Ace" said Hewitt. "It's at least 10, 15 degrees hotter on court than it is sitting in the stands purely because of the Rebound Ace surface."
Stosur said there's no logical reason for the high toll on players.
"We've all supposedly had an offseason, and had a break and been training," said Stosur.
"Any time you play a tournament the week before a Grand Slam, everybody is a bit careful about what they do. But having said that, if you enter a tournament, everyone hopes they can go through with it and then to finish it off."
Hewitt wouldn't be drawn on the seriousness of some of the injuries.
"Only that person can actually know whether they can go out there and are going to make it worse for next week or not," said Hewitt.
"Physically, I know there are a couple of people not feeling well, feeling sick, whatever. We can't say one way or another whether that's right or wrong. Only they really know."