@kourtneykardash / Instagram 1 / 8
@kourtneykardash / Instagram 1 / 8

She's gonna feel that in the morning! After a short layoff, Kourtney Kardashian was back in the gym with her trainer this week, and it sounds like he made up for lost time.

The eldest Kardashian posted two bathroom selfies one Instagram on Feb. 17 sporting black workout pants and a black sports bra. The images show off the mother of three's impressively toned physique.

"Don has been gone for 10 days but he is back!," she wrote of her trainer Don Brooks, adding that he pushed her to her limits. "He almost made me throw up...love those kind of workouts."

In a side selfie that showed off her toned tummy, Kourtney wrote, "I needed this."

Recently, Kourtney's trainer said he puts the reality star through a series of intense cardio and resistance moves during their 45-minute training sessions, which they do three to five times a week.

Around the same time as her selfies, Kourtney took to Twitter to tell her fans what she was listening to during her beast-mode sessions. Perhaps, not surprisingly, her fitness soundtrack hits close to home.

"The Life of Pablo just took my workouts to the next level," she wrote, referring to her brother-in-law Kanye West's newest album. She later added, "Warning: when listening to Highlights in the gym and @ElDeBarge and @TheKingDream sing, you may start singing really loud." She added the hashtag "#TheLifeOfPablo."

Aside from helping her with her figure, Kourtney said the gym helps her with her anxiety, too.

"Of course, when I'm having an anxious day, my workout is so much harder," she wrote on her subscribers-only app, KourtneyKardashian.com, last month. "But that's when it feels good to power through it! I try to exercise 5 days a week.

"My anxiety is always worse in the mornings so that's when I schedule my workouts. I usually start with a quick run or jumping rope to warm up. I have to do something fast to really kill it. And I definitely need good music."

Sounds like she's got the music part covered.