Watch Brie Larson Beast Her Way Through This Set of Bulgarian Split Squats

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Captain Marvel fans already know that there are seemingly few physical challenges Brie Larson can't conquer. From 400-pound hip thrusts to 100 sit-ups in five minutes and literally scaling a 14,000-foot mountain like it's NBD, the actress knows a thing or two about getting into superhero shape.

Beyond showing off her fitness feats on social media, Larson is also refreshingly honest about what it takes to get through a tough workout. In a video shared Wednesday on her Instagram page, Larson is heard grunting loudly through an entire set of Bulgarian split squats while working out with longtime trainer Jason Walsh. During Wednesday's sweat sesh, Larson is seen doing the rear-elevated squats with weights in each hand, testing her balance, stability, and strength. (Last year, Chelsea Handler even commemorated her 45th birthday with this killer leg workout.)

If you needed another reason to be impressed with Larson's training, Walsh — who has also worked with Emma Stone — added Wednesday that the 31-year-old actress took a major leap with the total weight. "These were 45-pound Blocks and we progressed to 65-pound blocks for singles! 👏👏👏 good grind," wrote Walsh in the comments of Larson's Instagram post. Larson was also proud to push beyond her limit. "Doesn't always look pretty but gosh it feels amazing," she captioned the video. (Related: Brie Larson's Insane Grip Strength Is All the Workout Inspiration You Need)

Walsh also told Shape that he and Larson worked with Powerblock dumbbells and how the Bulgarian split squat is a "really great exercise to exploit any imbalances from each leg, helps create strength and stability for the hips."

The Bulgarian split squat "targets everything: the quads, inner and outer thighs, hamstrings, calves, hips, and butt," said Cat Kom, founder of Studio SWEAT OnDemand, previously told Shape. She also called this workout a "total-leg destroyer" and told Shape "nothing makes me feel so satisfyingly sore the next day."

Really focusing on form is critical if you want to get the most out of Bulgarian split squat. You need to have strong core stability and recruit all the major muscle groups in your lower body to perform this exercise effectively. To do it, step one foot back, resting it on an elevated surface, such as a weight bench as shown in Larson's video. With the other foot planted in front of you, you'll bend both legs, keeping your chest lifted, and press through the front heel to stand. To follow Larson's suit, you can also hold a free weight in either hand or one heavy weight goblet-style in front of you. You can also do this move with just your body weight. (Check out these other leg day exercises trainers want you to add to your workouts.)

In Wednesday's video, Larson managed to lower her back leg until her front thigh was parallel to the ground — no easy task — engaging her glutes to straighten her standing leg without locking it into place (a no-no for your knees). She did a handful of reps on each side with added support from Walsh, who cheered her on every step of the way, before sitting on the bench and exhaustedly declaring, "I just stared into the void."

This butt-and-thigh-burning exercise is no joke, as evidenced by Larson's pure exhaustion at the end of a few reps. That's why trainers love it so much, with Pearla Phillips, certified personal trainer and owner of Fit Body Transformations in Epping, NH previously telling Shape, "[Bulgarian split squats] not only will give your legs strength and definition, they also engage your core and work your balance at the same time," which allows you to "work smarter, not harder while reaping better results."

- 170 Available at Dick's Sporting Goods

If you want to try Larson's move on your own while adding in weights, try the PowerBlock Sport 24 Adjustable Dumbbell System (Buy It, $170, dickssportinggoods.com). While these weights only go up to 24 pounds, they're perfect for working your way up to Larson's Captain Marvel level of strength. It's totally cool if you grunt the entire way through — whatever it takes, friends. Whatever it takes.