Heels together done with a WERKSAN 20 Kg bar. The bar wants to turn out so, I make sure the bar stays close and touches the Traps at the bottom of each rep. by insisting on this, I am making sure the bar path IS a true Behind the Neck Press even though its being done with one hand. Again, I am using Heels Together to make sure its the shoulder & arms doing the work NOT the legs! God Bless!!