MELBOURNE Jan 23 (Reuters) - When the professional tennis tours decided to shorten their respective seasons a few years ago, it was hoped it would extend the longevity of players at the top and cut down on the number of injuries.
At this year's Australian Open, though, players were once more dropping like flies, denting the draws and leaving the physiotherapists at Melbourne Park severely overworked.
The nine first-round retirements, eight men and one woman, equalled the record for the most retirements or walkovers in a grand slam event.
Many of them, including the withdrawal of Palona Hercog of Slovenia after just one game, were clearly a result of a pre-existing injury.
Others, like Czech Radek Stepanek, suffered an injury early in the match and were unable to finish.
The WTA Tour ends in late October, giving the leading women nine weeks off, while the ATP Tour has a seven-week break after the conclusion of the ATP World Tour Finals in London in early November.
The spate of retirements in Melbourne have led some to question whether players are not taking advantage of the longer break to rest their bodies but instead over-training in the off-season.
It may not be as simple as that.
Andy Murray, who famously uses the off-season to train hard in Miami, said there could be any number of reasons for a high number of injuries at this time of year.
"There's a big difference between someone having a muscular injury and twisting your ankle," the Wimbledon champion said.
"Twisting your ankle is bad luck. If there's a lot of muscular sort of injuries and stuff, then that's something different. That can be down to either not training hard enough or training too much.
"Sometimes, if you've been in Europe for a long time and it's freezing cold, coming to this heat, guys can get exhausted pretty quickly, muscles get tired faster.
"When your muscles get tired, it puts pressure on other parts of your body."
The injuries continued into the second week in Melbourne as Serena Williams and Maria Sharapova both suffered problems as their title chances bit the dust.
Williams' coach, Patrick Mouratoglou, said he thought it was most likely down to the difference between practice and competition.
"All the players, you can ask them, if they practice for four hours, every day, for two months, then the first match they play, they're going to be so sore, because competition is completely different," he said.
"They push themselves much more. Even though they feel they push themselves 100 percent in practice, that's not true.
"Stress plays a very important role in that. Because of the stress they also sometimes hit the ball in extreme positions, which can lead to injuries."
Murray, who did not play between September and late December after back surgery, agreed.
"We push ourselves hard in training and in practice, but playing matches, you always will tend to push yourself that little bit harder," he said.
"No matter how much training you've done, you might have been training for four weeks in December, you can wake up after playing the first match and feel terrible just because you're going that few percent harder."
For the past few years, Mouratoglou has taken his players to a training camp in Mauritius in December.
The last month of the year is one of the few opportunities players have to work on technical changes to their game, which Mouratoglou said can be a problem in itself.
"Every technical change, especially if you repeat it every day, can also bring an injury," he said.
"If you're not used to working on a physical aspect, because during the year you cannot, and then suddenly you focus on it too much, then you can also have an injury.
"There are 100 reasons to have an injury because you have a pre-season and you're away from competition.
"The off-season is the time to improve physical things but you also have to do it in a clever way, always step by step, always giving enough recovery." (Reporting by Nick Mulvenney; Editing by John O'Brien)