MELBOURNE, Jan 28 (Reuters) - Novak Djokovic said on Wednesday that the off-season can be a "two-edged sword", with the physical and mental workload players undertake to improve their game sometimes leaving their bodies under strain before the new season even begins.
The 38-year-old marched into the Australian Open semi-finals in search of a record-extending 11th title at Melbourne Park and a standalone 25th Grand Slam crown, but his progress has come amid a streak of unfortunate injuries for his opponents.
Italian fifth seed Lorenzo Musetti was forced to retire from their quarter-final on Wednesday despite leading 6-4 6-3 1-3, a round after Czech 16th seed Jakub Mensik also withdrew with injury.
"There's been a lot of talk about the schedule," Djokovic told reporters. "From one point of view, you would say, well, the players have rested and trained to get themselves into a good physical, emotional, mental game state to perform well and have no reason for an injury.
"But it's kind of a two-edged sword. The off-season is the only time you can really push yourself physically, but also, mentally, emotionally, on the court in terms of tweaking certain things about your game and improving and trying to put more effort than normally you would during the season.
"For most of the players, on a competitive tournament, official tournament, for maybe a month and a half or two months, and coming into new season, obviously body is behaving differently when you are playing official match than playing practice sets.
"So that's one of the factors as well that I feel like is influencing the walkovers or the injury issues that we've been seeing."
He acknowledged that his own body has reacted differently in recent years.
"I haven't had any big major injuries in Australia for most first part of my career, but then the last five or six years I've had pretty much every year an issue," the Serb said.
Heat adds to players' strain.
Tournament organisers invoked the Australian Open's extreme heat policy on Tuesday as temperatures soared past 40 degrees Celsius (104F), halting play on outside courts and closing roofs on the main arenas.
The tournament's heat stress scale had hit its maximum threshold of 5.0 on Tuesday afternoon.
"It's a very physical game. Today's example with Musetti shows how challenging this sport is," Djokovic said. "He was a better player on the court. He was close to winning it. He was in the control, and then obviously something happens."
Djokovic, who took a medical timeout to treat a blister against Musetti, said it remains his only issue ahead of a semi-final showdown with two-times defending champion Jannik Sinner.
"I had a blister that needed to be looked at and retaped," he said. "That's the biggest of my concerns. I don't have any other major issues."
(Reporting by Pearl Josephine Nazare in Bengaluru;Editing by Christian Radnedge)
