Thanks ADA, this version is primarily targeted for the the external rotators of the hip or deep muscles of the glutes. To make it work well the upper body needs to be stable and as upright as possible. Once the the feet are placed well allow the knees to open wide and keep the arms straight and shoulders stable. As the legs go up and down do your best to keep the heels together and that ought to send the work straight to its target. I hope this helps! Thanks for asking!