Remember that scene in Jurassic World where Chris Pratt’s character is working with his Velociraptors? This exercise replicates his movement in this scene that won zookeepers fame across the globe for “Pratt Keeping”.
The Harpy Eagle is just a more modern version of the Velociraptors that Pratt was training. You do need a leg band to do this exercise, but I believe a pair of old socks tied together to form a band will suffice in a pinch.
Place both legs inside a resistance leg band. Take a step backwards, as far as band will allow you to step. Bring other foot to meet before stepping back on that foot.