Pre-season training is in full swing for players as they gear up for the upcoming 2018 campaign.
Nadal is expected in Abu Dhabi imminently for the Mubadala World Tennis Championship exhibition event which will also feature Novak Djokovic.
While Federer will travel to Perth, Western Australia in the coming days for the Hopman Cup which begins on December 30.
Nadal, the world number one, withdrew from the ATP World Tour Finals with a knee problem while the gruelling season appeared to catch up with Federer as he lost to David Goffin in the season-ending event.
They are likely to be the favourites heading into the Australian Open after dominating the 2017 season.
And Henman says the quick turnaround in seasons is part and parcel of being a top player.
Henman told Express Sport: “That’s what as a professional tennis player, you are incredibly aware of.
“The season really is 11 months of the year. You try and have a little bit of a break, especially if you reach the ATP World Tour Finals.
“You get about 10 days of probably doing nothing then you’re back in pre-season, the physical training then back on court.
“It’s an incredibly short turnaround.”
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