Celebrity trainer Harley Pasternak wants you to get back — literally. He created this 15-minute workout to strengthen your back and butt to improve your posture and create a longer, leaner look. Grab a pair of medium free weights and get ready for a real booty burn!

If you love this workout, be sure to check out Harley Pasternak at the Propel Co:Labs Fitness Festival in LA (May 5-6), Miami (June 2), New York (July 14), and Chicago (Aug. 11). Get your tickets here [1].