The Limbo exercise works your back, arms and abs.

This movement is called the limbo. You're gonna start facing the TRX with your feet parallel, holding loosely with one arm. You're gonna let your body weight drop back, reaching for the ground there. With one arm, you're gonna pull the [unk] in towards your side and grab the TRX. So quickly, it looks like this. Right here, keep those abs strong. Give a little extra squeeze from the glutes there right from your butt.