Carrie Underwood's Secret for Keeping Workouts Interesting Is a Deck of Cards

The singer tells SELF how she makes fitness a priority—even if that means doing pull-ups at the park.

For Carrie Underwood, there is no such thing as a "typical" week of workouts. But whether Underwood is demoing moves at a photo shoot for her activewear brand CALIA by Carrie or chasing around her 3-year-old son, Isaiah Michael, she always finds a way to keep moving.

"I just try to fit things in wherever I can," Underwood recently told SELF at a New York City event for CALIA. "My son goes to a 'Mother's Day Out' program two days a week, so I can try to bank on those two days. I'll drop him off at school and go to the grocery store, then come home and work out." She uses those precious moments of free time to run the 3 miles around her neighborhood, which she tries to check off her to-do list in 30 minutes. Other days, she'll work out with trainer Eve Overland via Skype.

When she has a whole precious hour in the gym to herself, she likes to turn working out into a card game.

To keep her workouts interesting, Underwood turns to a deck of cards. "I'll assign a move to each suit, then flip over a card and do the number of [reps that corresponds with the number]. So if it's an eight, I'll have to do eight push-ups," she says. For a total-body workout, she'll make sure to include an upper-body move, lower-body move, abs work, and cardio. "I'll do things like push-ups, pull-ups, and sometimes I'll assign a suit to running on the treadmill and I'll run a quarter mile." She also tries to work in some moves on the BOSU ball.

The card game serves two purposes for Underwood: It keeps things fresh and saves her the energy of having to plot out an exact workout. "You don't have to think too much," she explains. When she doesn't have cards on hand, she'll improvise a similar system using dice—assigning one move to each number on the die, and then doing 15 reps of whichever move she rolls.

As fans have noticed on Instagram, Underwood's husband and son are occasional uninvited guests in her home gym.

"My son crashes my workouts a lot. It's really sweet and sometimes it's like, 'OK, I guess I'm done working out now because he's not letting me do things,' which is just being a mom," she says.

But even when life gets in the way of her pre-planned workouts, she manages to sneak in movement wherever she can. Playing with a toddler is its own form of cardio, but she tries to do double duty whenever she's outside with the family. "We try to be active as much as we can," says Underwood. "There's a little mini park in our subdivision, so I'll take [Isaiah Michael] to that and try to get in some pull-ups or some steps. There's a bench, so I can do some tricep dips."

Both cardio and strength training play a role in her routine.

Last time Underwood spoke to SELF, she had just started strength training. Over a year later, how has her lifting progressed? "The more I work with weights, the more I love them," she says. But when she craves an endorphin rush, Underwood opts for a run. But for someone as busy as she is, strength training is usually a more efficient way to fit in a workout. "I really enjoy it," she adds.

Underwood had to take a break from fitness after her fall in November—but still managed to maximize her time off.

Last November, Underwood fell on the steps of her home and ended up with a broken wrist and needing 40 to 50 stitches in her face. Underwood had to take a break from her physical lifestyle, including playing with her son. With her love for efficiency, it's no surprise that she even managed to be very productive during her healing time. "It did allow me more time to write and to produce and do all the stuff with my music," she says. "There were definite rough, scary patches, but there were some silver linings as well."

After an afternoon of burpees, sit-ups, and treadmill runs, all while dressed in her latest CALIA by Carrie collection, Underwood says, "Every day I feel a little more like myself."