Strong is the new skinny: Model Nina Agdal shows off muscular back as she posts topless workout snap

PUBLISHED: 12:35, 22 April 2014 | UPDATED: 17:56, 22 April 2014

She has an amazing figure but fashion model, Nina Agdal proved that it takes a lot of work to keep in shape.

The 22-year-old posted a topless image of her muscular back to her Instagram account on Tuesday, captioning it with the words: '#progress skinny doesnt mean weak.' [sic].

She also looked like may have been sporting a spray tan in the snap in which she piled her hair on top of her head.

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She's made of strong stuff: Model Nina Agdal posted a picture of her muscular back to her Instagram account on Tuesday

But the health-conscious star's lifestyle has it's downfalls at times and Nina jokingly tweeted: 'Started my day off with a grapefruit squirting directly into my eye. Nice.'

Talking about her fitness regime, she told MailOnline: 'I try to work out at least four times a week for an hour.

'I personally enjoy going to Barry's Bootcamp; it's such a great work out. It's hard but afterwards you feel like you can take over the world.'

Racy lacy: On Monday, Nina attended the New Yorkers For Children annual spring benefit at the Mandarin Oriental in New York

Girls together: Posing with her pal, Selita Ebanks, Nina showed off the results of her hard work in a gorgeous Marchesa Notte dress

The pretty lady was recently pictured showcasing her figure when she attended the New Yorkers For Children annual spring benefit at the Mandarin Oriental on Monday.

The Sports Illustrated model looked incredible in a long black lace dress by Marchesa Notte which showed off her curves.

Last week, she attended the Kiehl's Ride For Charity at their flagship store on Thursday. She barely broke into a sweat as she worked out on an exercise bike alongside Entourage star Jeremy Piven.

In a spin: Last week, Nina worked out on an exercise bike at the Kiehl's Ride For Charity event in New York

The cover girl will soon be joining the cast of Entourage as she makes a sizzling cameo appearance in the forthcoming movie which follows on from the HBO hit series.

In January, Nina was spotted filming party scenes aboard a yacht in Miami, Florida, alongside castmembers Adrian Grenier, Jerry Ferrara, Kevin Connolly and Kevin Dillon.

Fans who loved the original series will have to wait until next year to see the movie, which is slated for a June 12, 2015 US release.