Contrast the Magic of the bending right elbow with a " preserve the triangle" method. The switch from one to the other revolutionized my game. Something Lynn learned from Homer Kelley in 1982. He saved himself the decade of grief that a lot of people endured.
Getting really "wide" was a great companion to Covering the straight line Base Line (Steering of a sort), back in the day. What I'd give to be able to go back in time and correct that death move of mine.
For what Homer said about preserving the triangle you can key word search " Mallard".
Seems to me the tucking under of the hips would limit the hula hula hip action and clearing the right hip. Might lead to a sway down the target line and a big steer if not carefully monitored.
Proper hip action does no lead to a bad back but can be used to pull the body into a straight up alighnmant without added stress to the spine. If anything it aleviates stress on the spine.