He was bothering the players on the other court.That's a great video.
110% agree with rec player forgetting about hip. Just go for good turn and hips and shoulders will coil naturally. Then just view extra turn as longer range of motion for shoulder uncoiling ... shoulders and hips uncoil together ... smooth gradual acceleration increase into contact.
I actually do not think all active elements in tennis strokes adds tension ... and I bet we do a lot more active elements than we are aware of. For example ... we grip hard enough to not drop the raquet ... and use arm muscle to control backswing and swing path. I hit with a eastern (probably weak eastern) so experimenting with flip fh was difficult to get in full lag position. Not a grip tension issue ... have always had light grip pressure. My solution to at least get the feel of a flip fh was to simply give a slight active roll to the right in flow with the weightless bottom of swing right before swinging forward. There was zero difference in grip pressure or arm tension ... but major difference in amount of lag. I think players think because it’s muscle memory and not thought of anymore it has no active elements. Same thing happened learning lag on 2hbh. Simply using momentum of racquet coming around in backswing ... a slight active element of putting hands/racquet in full lag with rh drop added zero tension or grip pressure. All in the flow.
If we are going to revive WTA vs ATP ... I just thought I would revive “flip happens automagically or you are doing it wrong” war.