Wondering how Kim keeps that envious figure? Well, her now famous trainer, Melissa Alcantara, took to social media to reveal Kim’s grueling workout regiment.

Mrs. West introduced us to Melissa in a KUWTK episode where she asked the Instagram fitness influencer to train her. And so, Kim’s intense fitness journey began in early 2016. Her primary routine consists of weight training, but as the latest posts show, her cardio isn’t for the faint of heart.

“She actually did 15-minute banded StairMaster,” said Alcantara with a shocked emoji in response to Kim’s snap of climbing the StairMaster with a band around her thighs. After the cardio warmup, Kim does five back-to-back rounds of 30-second dumbbell shoulder thrusts (with 10-pound dumbbells), a 30-second rest, then one minute of mountain climbers.

In 2018, Kim posted a big thank-you to Melissa, crediting her trainer for the fitness transformation:

“Shout out to my trainer @fitgurlmel, who really changed my body. When I wasn’t happy with what I saw back in the mirror I spent a whole year training so hard 5 or 6 days a week putting in a lot of work and changed the way that I eat and there’s such a noticeable difference. I am firm and [have] less cellulite and [am] so much more confident. SO THANK YOU for waking up at 5 am to do crazy body building workouts & sprints that I hate & putting me on to this lifestyle.”