It’s no small feat that Kristin Cavallari has totally ripped abs. She works hard in the gym to achieve such a toned tummy. The reality star shared her grueling fitness routine that included heavy weights in a Thursday, May 12, Instagram Stories video. Shen then posted a photo from afterward in a halter crop top and leggings showing her incredible abdominal muscles.

Kristin, 35, was seen with her back leaning against a weight bench with a long bar with at least 40 pounds of weights on either side of it sitting across her midsection. She performed a series of upward hip thrusts, which was quite the workout! The former MTV star let out a few power grunts and plenty of strong breaths to keep her going throughout her set.

Kristin Cavallari Ripped Abs Crop Top
Courtesy of Kristin Cavallari/Instagram

“Got after it with Kevin Klug,” Kristin captioned the video, giving props to her Nashville-based personal  trainer for helping her get through a tough workout.

But it was so incredibly worth it. Kristin shared a mirror selfie after her session was completed and her ab muscles looked so taught and engaged from the exercise, which also firms the glutes as well. “Being done is the best f–king feeling,” she wrote over the photo, celebrating how amazing she looked after putting in her demanding gym time.

It’s amazing Kristin finds the time to get in her workouts with her busy lifestyle as a successful businesswoman and a mom to three young kids. She has her thriving Uncommon James lifestyle and jewelry brand and had expanded into the skincare market with Uncommon Beauty.

But Kristin’s favorite job will always be mom to her three kids she shares with ex-husband Jay Cutler: sons Camden, 9, and Jaxon, 8, and their little sister, Saylor, 6.

The former The Hills alum doesn’t share her children’s faces on social media, although they do make appearances. Kristin recently celebrated Jaxon’s May 7 birthday by holding the bottom of a large gold mylar “8” balloon from his shoulders up in an Instagram photo. “I want my kids to make their own decision to be on social media instead of me making it for them,” she noted in his birthday post.

“Jaxy, my little Mozzy, you are the funniest kid I know. Always up for a good time, you are pure light my love. Part rebel, part kind, sweet soul, there’s never a dull moment with you,” Kristin wrote in his tribute, adding, “Keep being you and growing into this incredible young man. I love you more than you’ll ever know.” The Very Cavallari alum definitely burned off any birthday cake she had that day with her grueling gym session!