Fitness model Maggie Russell is training for the World Beauty, Fitness and Fashion competition in Australia and has a vigorous workout that makes us tired just thinking about it.

According to the 20-year-old, she works out four hours a day and eats 1,100 calories. So basically, her body is just muscle – like, A LOT of muscle.

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And while her waist is incredibly tiny, her butt is a whole other story.

Scroll through the gallery to see more Instagram models who have ~booties~ that people buzz about.