All You Need Is a Pair of Socks to Do This 15-Minute Total-Body Workout From Carrie Underwood’s Trainer

No equipment—not even shoes—is required.

You don’t need to hit the gym to get a great workout. Heck, you don’t even need equipment—or shoes.

For proof, check out this five-part bodyweight circuit that celebrity trainer Erin Oprea shared on Instagram on Monday. It’s a challenging, yet beginner-friendly sequence that you can do at home in just your socks.

“I was inside and [feeling] lazy and was like, Just get up and do something,” Oprea, whose famous clients include Carrie Underwood and Kelsea Ballerini (among others), tells SELF of the inspiration for this circuit. “I didn’t want to put on a jacket, I didn’t want to put on shoes,” and thus the sock-centric workout was born.

The circuit targets practically every muscle in your lower-half while also giving you both cardio and balance work.

The first portion of the circuit—a three-part lunge series—works your legs from multiple angles. You’ll strengthen your quads, outer thighs, inner thighs, glutes, hamstrings, and calves. The reverse lunges in particular work your quads and glutes; the curtsy lunges hit the outside of your glutes; and the lateral lunges target your inner thigh muscles, says Oprea. All three variations will challenge your balance, too, she adds. The last two moves in the circuit—plank jacks, and mountain climbers—will deliver an extra challenge to your shoulders, glutes, and core, she explains.

On top of the strengthening and balance benefits, the sequence gives you a stellar cardio workout. “All of these moves will get your heart rate going,” says Oprea.

By doing these movements with socks, you’re actually getting even more of a strengthening challenge than if you performed the OG versions.

When you perform the traditional versions of these five exercises, which all involve picking your feet up off the floor during certain portions of the movements (like when lunging in any direction, or jumping your feet out and in during the plank jacks, for example), you give your muscles a micro break every time your limb(s) is lifted.

By keeping your feet continually grounded, however, you’re keeping the muscles continuously engaged throughout the reps with no reprieve, explains Oprea. “There’s more time [that your muscles are] under tension,” she says.

Here’s how to do the five-part circuit, plus, advice for scaling the difficulty to match your fitness level.

As mentioned, you can do this entire circuit on hardwood (or another type of smooth, hard surface) in just your socks. If you don’t have hardwood, you can complete the moves on carpet by placing a glider, paper plate, paper towel, or even a plastic food storage container lid (essentially, anything that slides well on carpet will work) beneath the sliding foot (for the lunges) or both feet (for the plank jacks and mountain climbers).

You’ll complete the following circuit three times through with no break in between the moves. (Of course, that's the ultimate goal—if you feel you need to take a break to catch your breath, you should do what's right for your body and work up to nonstop movement as you get stronger.) Then, rest about 1 to 2 minutes in between each circuit. For this rest, you can either relax completely, or jump rope for active recovery, says Oprea. Allot about 15 minutes for the total workout.

Reverse Lunge — 15 reps each side

  • Start standing with your feet shoulder-width apart. Put your hands on your hips, clasp them in front of you (like Oprea demos), or put them behind your head. If using a glider (or substitute), place it under your left foot.

  • Raising your left heel off the ground, press through the ball of your left foot to slide your leg back about two feet as you bend both knees to lower into a lunge, creating two 90-degree angles with your legs.

  • In this positioning, your shoulders should be directly above your hips and your chest should be upright (a slight forward lean is OK, as long as your back is flat and not arched or rounded forward). Your right shin should be perpendicular to the floor and your right knee should be stacked above your right ankle. Your butt and core should be engaged.

  • Push through the heel of your right foot as you slide your left foot in, pausing when your foot is about halfway back to the starting position. This is 1 rep.

  • Do 15 reps and then switch legs for another 15 reps.

By staying low and not fully standing between each rep, you’ll maintain more tension and challenge your muscles more, says Oprea. Also, be sure to keep the weight on your front heel as you slide your other foot in to engage your glutes, and keep your core tight throughout for stability, she adds.

To make these lunges (and the lunges below) more challenging, hold a dumbbell in each hand, says Oprea. To make the move easier, hold onto the back of a chair with the hand of the forward leg or place it against the wall for extra stability. You can also stand all the way up in between each rep to reduce the tension on your legs.

Curtsy Lunge — 15 reps each side

  • Start standing with your feet shoulder-width apart. Again, put your hands on your hips, clasp them in front of you (like Oprea demos), or put them behind your head. If using a glider (or substitute), place it under your left foot.

  • Raising your left heel off the ground, press through the ball of your left foot to slide your leg diagonally behind you as you bend both knees to create two 90-degree angles with your legs.

  • In this positioning, your shoulders should be directly above your hips and your chest should be upright (a slight forward lean is OK, as long as your back is flat and not arched or rounded forward). Your right shin should be perpendicular to the floor and your right knee should be stacked above your right ankle. Your butt and core should be engaged.

  • Push through the heel of your right foot as you slide your left foot in back to the starting position. This is 1 rep.

  • Do 15 reps and then switch legs for another 15 reps.

On the leg that’s stationary, make sure that the area from your knee to the ankle stays perpendicular to the ground, says Oprea. Don’t let it angle sideways—this will help engage the side of your butt, she explains.

Lateral Lunge — 15 reps each side

  • Start standing with your feet hip-width apart. If using a glider (or substitute), place it under your right foot.

  • Slide your right foot straight out to the side as your bend your left knee, hinge forward at the hips, and push your butt back into a lunge.

  • Keep your chest lifted and core engaged.

  • Pull your right leg back as you stand up straight and return to the starting position. This is 1 rep.

  • Do 15 reps and then switch legs for another 15 reps.

Keep your chest up and shoulders back and engage your core for stability. The sliding leg should stay locked and straight throughout the reps, says Oprea. This will help you stretch your hamstrings and get lower. The stationary leg, on the other hand, should remain slightly bent. With that leg, make sure to push back into your hips so that your knee doesn’t extend beyond your toes, says Oprea. The goal is to get that quad parallel to the ground, she adds.

Plank Jack — 30 seconds

  • If using gliders (or a substitute), place them under both feet.

  • Get in a high plank position with your arms shoulder-width apart and your wrists directly under your shoulders. Your core, butt, and quads should be tight, and your back should be straight (not arched or rounded).

  • Maintaining the good plank position described above, slide your feet apart and then immediately bring them together again. As you move, think about keeping your hips as stable as possible and avoiding bouncing your butt up and down.

  • Continue sliding your feet in and out for 30 seconds.

Though Oprea busts out these reps at a fast clip, you should focus on form rather than speed when doing this move. “You’re not just free flying your legs,” says Oprea. Think about squeezing your glutes and quads as your legs glide in and out in a very controlled manner. You’ll also want to keep your butt down as you move your legs. “It’s not bottoms up, it’s bottoms down,” says Oprea.

For a more beginner-friendly version of this move, simply hold a plank for 30 seconds.

Mountain Climber — 30 seconds

  • If using gliders (or a substitute), place them under both feet.

  • From a high plank position, engage your core and slide your right foot forward to bring your right knee to your chest. You should move at a quick, but controlled, pace.

  • Return to the starting position and immediately draw your left foot forward to bring your left knee to your chest.

  • Continue this movement, alternating legs, for 30 seconds.

Keep your butt down as you complete the reps, advises Oprea. If you need to dial down the intensity of this move, simply reduce your speed.

Lastly, we'll leave you with Oprea’s tip for crushing the circuit as a whole: “Put on some good music, laugh, smile, and have fun with it.”