Azarenka, Zverev and more put in off- season training

After the offseason vacation pictures come the proof that the players are hard at work training for the 2019 season. The pattern of Instagram-posting never fails to be predictable. There's Victoria Azarenka hoping to get her season off to a good start after a below-average comeback year.

Then there's world No. 13 Fabio Fognini showing off some power steps:

And Marin Cilic showing off a scenic run:

Kristina Mladenovic went from the Maldives with Dominic Thiem to the treadmill:

While her boyfriend also didn't waste any time:

Barbora Strycova, who played her last Fed Cup tie this year and won, has some serious ab strength:

And Alexander Zverev was similarly impressive strengthening his core:

While the most amusing video of all may go to Serena Williams, who preferred goofing off in the background while her hitting partner Jarmere Jenkins put in his round:

Expect to see a lot more training as the players all return to intense on-court sessions before the new year kicks off.