Training for a Spartan race is tough enough. But doing it when you have young children? That’s a whole new challenge, especially for a parent who’s home all day. There’s precious little time for anything that doesn’t involve feeding, playing with, watching over, or cleaning up after them.

So how do you break a sweat when you’re bringing up baby (or kids of any age)?

Caitlin Bailey, a Spartan SGX coach and senior trainer with Philanthrofit, a New York City–based personal training company, says it’s easier to sneak in a workout than most parents think. All you need is your body weight.

Bailey recommends doing each of the following exercises for one minute. Go immediately to the next exercise with no rest. After finishing all five, rest one minute. That’s one round. Build up to three rounds, Bailey says, “and you have a quick yet extremely challenging 18-minute workout that can be done anywhere, without any equipment, while your baby is sleeping or the kids are at sports practice.”

Exercise #1: Pushup

You can work your chest, shoulders, triceps, and core muscles, but only if you use good form.

*How to do it: *Get into the high plank (pushup) position with your shoulders directly over your wrists and your body in a straight line from neck to ankles. Bend your elbows and lower your body as a unit. Pause, then push your body back up to the starting position.

To make it more challenging, raise your feet onto a chair or coffee table. To make it easier, Bailey recommends this modification: “Once in the high plank position, bend your knees and place them on the ground.” Lower your chest to the floor, and then use your legs to help you push back up to the starting position.

Exercise #2: Reverse Lunge with Knee Drive

“Lunges are a great exercise that target the quads, glutes, and hamstrings while also requiring a lot of core stability to maintain your balance,” Bailey says.

By stepping back instead of forward, she says you’ll reinforce your proprioceptive awareness of how it feels to move backward. Many will also find it’s a little easier on the knees.

*How to do it: *Stand with your feet together, knees slightly bent, and abdominals braced. Step back with one foot and lower your body until both knees are bent about 90 degrees while keeping your torso upright. Push down through your front heel and, as you return to the starting position, drive your rear knee up to hip height. Lower that foot to the floor and repeat with the opposite leg.

Not challenging enough? Add an explosive jump off the front leg as you drive the back knee forward.

Exercise #3: Russian Twist (a.k.a. Cherry Picker)

While the pushup uses the abdominal muscles as stabilizers, this exercise (which goes by two different names) uses them as prime movers, especially the obliques.

*How to do it: *Sit on the floor with your knees bent and feet on the ground in front of you. Brace your abs and lean back as if you’re in a reclining chair. Place one hand on top of the other. Rotate your upper torso to the right and touch the floor just outside your right hip. Repeat to the left, again touching the floor with your stacked hands. Continue rotating from side to side.

Want a bigger challenge? Hold something in your hands, anything from a diaper bag to an infant, and do the exercise as described. Keep your core tight to protect your lower back, and stop if you feel any pain.

Exercise #4: Prisoner Squat with Calf Raise

“Squats are an amazing, functional exercise that can be done anywhere,” says Bailey. “And best of all, they can be modified or intensified with countless variations.”

*How to do it: *For this variation, begin with your feet just inside shoulder-width, your hands behind your head, and elbows out to the sides. Push your hips back and lower your body into a squat, keeping your weight on your heels, your chest up, and your elbows out. Return to the starting position and, in one continuous motion, rise onto your toes. Pause, feel the contraction in your calf muscles, return to the starting position, and repeat.

For a bigger challenge, jump as you come out of the squat, pointing your toes at the top. Land and go immediately into the next squat.

Exercise #5: Burpee

You knew this was coming, right? It’s not a Spartan workout without burpees, a signature exercise that tests your strength, endurance, and fortitude.

How to do it: Stand with your feet together. Bend your knees and drop until you can put your hands on the floor. Throw your feet back into the high plank position. Do one pushup. Jump your feet back toward your hands. Now throw your hands up in the air as you jump, fully extending your body before landing softly on your feet. Immediately begin the next burpee.

Ready to give Spartan a try? Here’s everything you need to know to find your race.