Bouncing on trampolines isn't just for children. It might just give you the edge you need on the WTA Tour.
Or perhaps success on the tennis court can be traced back to time spent in a boxing ring, halfway up an indoor rock-climbing wall, or in the middle of a dance floor.
For the WTA's athletes, boredom is the enemy when working out - when you start to lose interest, your application will begin to tail off, and then you won't have the conditioning you need for matches.
So many players don't restrict themselves to the gym and have instead embraced a number of other creative ways to stay fit, including kayaking, beach volleyball, working out in the sand dunes, doing exercises with a ladder, or running up and down flights of stairs.
Perhaps what matters most is enjoying yourself - if you're having fun, you're far more likely to continue for longer.
Among the most creative players is Johanna Konta, who has incorporated rock-climbing and trampolining into her routine.
"With the rock-climbing, I was fine with heights, but it is still just a whole mental process to just let go and fall flat. It was definitely an experience," she has said. "The first time I went up, I couldn't let go. It is not funny - I literally couldn't let go. I was hyperventilating, I was sweating, I was thinking: 'I can't let go.'"
Trampolining also presented a few challenges.
"I fell flat on my face. Nobody pushed me, I didn't trip, I just fell."
For Serena Williams, as well as many other players, dancing is just as enjoyable than running on the treadmill. To raise her heartbeat, Williams has tried a number of different forms of dance, including contemporary.
"I dance a lot when I'm healthy," she once told People magazine. "It's a fun way to get a workout instead of going to the gym and jumping on the treadmill for 30 minutes."
There are a number of similarities between boxing and playing tennis, with both individual sports demanding high levels of fitness, hand-eye coordination and focus.
Caroline Wozniacki, who once also ran the New York Marathon during the off-season, has put on boxing gloves to stay fit and to add some power to her arms.
"In both tennis and boxing, you need fast arms and fast feet," the Dane has said.
Which parallels can be drawn between tennis and kayaking? That was the sport that Samantha Stosur once tried during the off-season when she trained with Australia's kayak team.
"I really enjoyed doing a sport I had never done before - trying to keep up with the girls was very tough," Stosur has said, while she has also been seen running up and down town steps.
Maria Sharapova, meanwhile, has worked out on the sand dunes, Belinda Bencic uses a ladder, laid down on the ground, to improve her footwork (she jumps in and out of the rungs), and Victoria Azarenka has played beach volleyball.
Ultimately, tennis players need to find something that brings them pleasure as well as aching muscles.
"It's important to have fun with what you're doing," Wozniacki once said. "Because you can push yourself, train, try to get fit, but if you don't enjoy it, it's just going to last a certain amount of time."