Nicole Winhoffer [1] knows a thing or two about Summer bods. The stunning celebrity trainer who stars on Khloé Kardashian's [2] Revenge Body on E! has endless experience sculpting the bodies of top athletes, movie stars such as Ellen Pompeo [3] and Kate Hudson [4], and singing superstars like Madonna [5]. What do all her clients have in common? Killer arms! I asked Nicole for a move that I could do at home or on the road to get ready for sundresses [6] this Summer.

First things first — grab a prop! (And no, she doesn't mean some expensive equipment you have to go out and buy.) "I always think it's important to have a prop — that way you can add resistance and you burn more calories when your brain is focussed on another item. A towel is great because we all have a towel at home!"

Check!

"Take the towel and put it behind your back. Grip the towel with your palms down at the edge of the towel and pull the towel apart so that there is a really strong straight line that you are creating. So I like to say, no flaccid towels!"

(Did I mention Nicole is wildly funny!?)

"Then you want to pull that towel apart, palms down, and that way you're opening up your shoulders and your chest, and your heart because naturally we are hunched over."

Nicole explained so much of our life today is spend hunched over — driving, Instagramming (guilty!), working on the computer, etc., so she created this exercise to focus on the external rotators of our shoulders.

"My favourite muscles in the arms are Teres Minor and Teres Major, which are the small stabilizing muscles that can improve bra fat, and we really neglect these smaller muscles. This movement is for all three of those muscles."

Yes! Finally a way to address my pesky bra fat, which always seems to be there no matter how much I work out!

"Then you want to bring your elbows bending up toward the ceiling and release while you are pulling that towel apart. I'm big on high repetitions because I believe that what you repeatedly do is how you are, so what we are doing here is waking up new muscles, retraining the body and the shoulders to pull back, and in turn you're sculpting the muscles that we don't use in everyday life."

So there you have it! Nicole's number one arm move to get you sculpted for Summer. I'm off to find a towel . . .