Nick Kyrgios enjoyed the full freedom of a high-intensity practice session at Lyneham's tennis centre on Tuesday, as so many of his Australian Open competitors spent their hours desperately maintaining fitness and sanity in Melbourne quarantine.
As Kyrgios prepares for his first tournament in almost a year, a leading exercise scientist has labelled this year's chaotic Australian Open as a "once-in-a-lifetime match point" for Australian participants not required to endure a fortnight-long lockdown.
The University of South Australia's Professor Kevin Norton has highlighted the severe challenges facing the world's best players, who will be left with barely a week to prepare for the Melbourne tournament once they've completed their mandatory quarantine.
Norton said players who spend two weeks cooped up in a hotel room will face physiological and biomechanical decay, a loss of cardiovascular adaptations, reduction in decision-making ability and a significant disadvantage in acclimatising to the Australian Open's notorious hot temperatures.
It leaves the likes of Kyrgios and his compatriots a glorious opportunity to win their home grand slam.
"It's hard to quantify it with a number but I would say it's a very significant [opportunity]," Norton told The Canberra Times.
"The first thing that happens is that blood volume will shrink. That happens even in a 24-hour period if you're flying. Everybody knows you get dehydrated on a plane and all that sort of stuff, but if you're locked down and you can't do any intense exercise it's the same sort of thing.
"It's not just a matter of drinking water and your body fills up with water again. It's a physiological response to high-intensity training.
"Training induces increases in blood volume and circulatory function to help maintain heart efficiency, regulate muscle blood flow and oxygen delivery, as well as help control body temperature. It also provides a reservoir of fluid for potential sweat, which is essential for body cooling during elite competition.
"When you're in good shape you sweat. Often they'll sweat early in their exercise session and they'll sweat more, and that's really important for your body.
"After a few days of inactivity, most of these cardiovascular adaptations will be lost, exacerbated by the long-haul flights to Australia."
World No.1 Novak Djokovic is one of several players who have complained about the quarantine conditions, while reportedly providing a list of demands to Open organisers to improve quarantine conditions.
That led to Kyrgios labeling Djokovic a "tool" on Twitter late Monday night.
As of Tuesday afternoon there were 72 players confined to two weeks' worth of quarantine, leading many to creatively turn their hotel rooms into mini-training camps.
Kyrgios, who will head to Melbourne in late January, has meanwhile been training in his home town without the shackles of a hotel room.
MORE CANBERRA SPORT:
Norton praised the athletes' creativity in developing a hotel room exercise regime, but said the lack of exposure to Melbourne's summer weather would play a key factor throughout the tournament.
"We're talking about 10 days is typically how long it takes to acclimatise to heavy exercise in hot environments," Norton said.
"A week's probably pushing the limits and most of those players, they won't be acclimatised to training hard and competing in the heat. That's of most concern.
"Anything that goes beyond three sets will be almost impossible for those that have been locked up in quarantine because they just won't be conditioned."
Norton said two weeks in a confined space would also have a major bearing on decision-making in key moments.
"When you train hard in preparation for competition, the final two weeks is all about fast-twitch, fine-tuned decision-making under the most extreme speeds and fatigue," Norton said.
"They don't necessarily lose reflexes, but it's the accuracy of those reflexes.
"A little bit of the edge comes off, what we call choice response time, or decision-making capacity - sometimes it's called executive function.
"It's in the brain, it's the ability to pull information together and make a correct decision at speed."