In the faster-is-better world we live in, carving out 30 to 45 minutes a day for a good workout can seem like a major challenge — and that can totally mess with your quest for a strong core. Enter: the 7-minute workout.

This strategic, super-effective form of high-intensity circuit training is supported by science. To complement the original and give you even more 7-minute options, we consulted with a pro.

Yusuf Jeffers, certified personal trainer and Head Coach at Tone House in NYC, created a companion ab workout that requires only your body weight.

A killer combo of core-strengthening moves and cardio, this circuit is designed to “attack” not only your abs and obliques but also the muscles in your back, your pelvic floor, and even your shoulders, says Jeffers.

And, truth be told, it beats doing hundreds of crunches.

“If you’re training for a sport — or just for everyday life — you usually don’t use any one muscle in isolation,” he says. “This correlates closer to actual, functional movements.”

And that’s a good thing: While crunches certainly strengthen your abs, your body benefits more — by torching more calories, for example — from movements that recruit more than one muscle group.

Though it’s important to remember that high-intensity interval training isn’t meant to be a daily workout, it’s a great tool to have in your exercise arsenal, particularly on days when you’ve only got 7 minutes to spare.

Perform each move below for 30 seconds, resting for 5 to 10 seconds in between. Expect to do anywhere from 15 to 20 reps, but remember that quality always tops quantity, says Jeffers.

Don’t stress if your rep count is on the lower end the first couple of times you try this — there’s always room to improve. If time allows, you can repeat the circuit 2 or 3 times.

With this circuit, go big or go home. Try to work at the highest possible intensity for as many reps as you can manage in 30 seconds without sacrificing proper form.

1. Firefighter

Stand with feet shoulder-width apart and core engaged. Shift weight onto right leg and lift left knee, bending left leg to a 90-degree angle. Keep arms in front of you as if you’re climbing a ladder.

Extend left arm overhead as you push off right foot. Explosively lift right knee until it’s level with your hips. Pull hand down as you lower your right leg. Repeat on the other side.

Continue alternating legs and arms as fast as you can. This should feel as intense as high knees (No. 5).

2. Knee-in crunch

Lie faceup with fingertips behind ears and legs extended. Lift legs until feet are about 6 inches off the floor. Engage core and lift shoulder blades off the floor.

Come up like you’re doing a regular crunch while also pulling knees in toward chest. Careful not to pull on your neck — use your abs to lift. Reverse the movement to return to starting position.

3. Glute bridge

Lie faceup with knees bent and feet flat on the floor. Place arms on the floor by your sides, palms facing down. Keep head and shoulders firmly planted on the floor. As you inhale, press through your feet. As you exhale, squeeze glutes to lift hips off the floor.

This exercise is great for hip stabilization and for boosting ab strength — plus, it works your butt (bonus!).

4. Bicycle crunch

Lie faceup with fingertips behind ears, knees bent at a 90-degree angle, both feet off the floor. Lift head and shoulders off the floor.

Bring right elbow to left knee as you extend right leg straight. Quickly reverse the movement to repeat on the other side, bringing left elbow to right knee. Continue to alternate.

5. High knees

Stand tall with feet hip-width apart. Engage core and use lower abs to lift and lower one knee at a time, as if running in place.

Bring knees to the same height as hips, thighs parallel to the floor. Try not to lean back. Stay on the balls of your feet and alternate legs as quickly as possible.

6. Reverse crunch

Lie faceup with arms at your sides, palms facing the floor. Bend knees so hips and knees form 90-degree angles. Engage core.

Activate lower abs to lift hips off the floor, bringing knees toward chest. Lower back down to starting position as slowly as possible to keep your lower abs engaged.

7. Mountain climber

Start in high plank position with core tight and hands directly under shoulders. Keep core engaged to stabilize hips as you drive right knee toward chest.

Return right leg to starting position, then repeat with left leg. Continue alternating legs to pump knees as fast as possible.

8. Windshield wiper

Lie faceup with arms straight out to sides (so your body forms a T) and legs extended. Raise both legs toward the ceiling until they’re perpendicular to the floor.

Without lifting head or shoulders off the floor, lower both legs to the right, as close to the floor as you can get without losing form. Reverse the movement to lower both legs to the left. Continue to alternate like — you guessed it — windshield wipers.

9. Push Jacks

Stand with feet together, elbows bent, palms facing up. Quickly jump feet apart and pump arms up toward the ceiling (like you’re raising the roof). Reverse the movement and repeat as fast as you can.

10. Pike-up

This move gets both your abs and shoulders in on the action.

Start in high plank position with hands directly under shoulders. Engage core and lift hips high as you jump your straight legs forward.

At this point, your body should look like an upside-down V. If hamstrings are too tight to fully extend legs, keep a slight bend in knees. Jump back to starting position.

11. X-up

Lie faceup with arms at your sides. Engage core and sit up. Raise right hand and left leg simultaneously. Touch right fingertips to left toes. Return to starting position and repeat with the opposite hand and leg.

12. Hollow body hold

Finish strong with an isometric hold. Lie faceup with arms by your sides and legs extended. Engage your abs and lift shoulder blades and legs off the floor.

Keep your lower back pressed into the floor throughout the exercise — the closer your legs are to the floor, the more challenging this is. Hold this posture for 30 seconds.

Now it’s time to put it all together. Perform as many reps as possible of each exercise, for 30 seconds each. Rest for 5 seconds between exercises. Repeat the circuit 2 or 3 times as desired.