Plaza Statement - A relaxed back makes your dancing..... soft and fluently!
In the Swing dances such as the Waltz and Foxtrot the men should take care of the frame and holdOften I see men when trying to maintain their hold that they are blocking the freedom of their shoulderblades en their dancing becomes to look restricted and stiff.
A soft swing action requires strong feet and a relaxed back allowing the body to swing forwards and to side free and fluently. That's what's makes your dancing more sensed to the music and your partner