Quiet and still are not good descriptors for the upper body imo because no part of the body is an island. If I elicit a grf that passes through my foot and up my leg to the hip, the chain reaction does not stop there.....in my experience as an ex-racer and instrucor/trainer, "quiet" can bring about more of a posed, robotic "instructor-y" look, when in reality skiing is fluid and dynamic.
Some examples of the active upper body whilst the legs turn include, but are not limited to, pelvic movement in all 3 planes, spinal movement in all 3 planes, rib cage (that's right!) movement in all three planes, etc....hardly what is call "quiet".
zenny
Not sure where "quiet" ever got associated with inactive or numb. The body can't even stand still ordering lunch at McDonalds without being active.
"Quiet" is an overall descriptor of looks, not a description of muscle activity. To be quiet involves moving the right parts at the right time. And that means moving now to put oneself in the right position later. That is likely the biggest requirement of a quiet upper body. The opposite would be a flailing upper body.
This tennis article from 2005 makes a similar point about the great, but apparently "robots", of tennis. Quiet upper body is related to balance.
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How 'Body Sense' Makes Better Tennis Players
by Rhys Thomas
...John McEnroe, Miloslav Mecir, and Marcello Rios led a revolution in which players made the game look easy by "quieting" the upper body during even the most aggressive strokes. This allowed them to play with completely vertical spines and relaxed arms. Rotation around this vertical axis increased power in their games and let their arms accelerate at the ball with much less raw strength than previous players required.
These players helped to create the footwork and balance that every top player uses today. They did not listen to coaches tell them to stop and hit, only to have to recover later. Instead, they listened to their "balance," began to recover before they hit the ball, and were on their way back to center at the contact point, making their movements seamless. ...
In the new millennium, Roger Federer has raised the bar even further. While his strokes are beautiful and his movement fluid, his most renowned trait is his ability to keep his upper body "quiet," his head still, and his neck relaxed. With little or no head movement, his vision is better, he has a better sense of where he is on the court in relation to the ball, and he can coordinate his body movements effortlessly. In short, Federer plays tennis in complete balance. ...
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http://www.ultimatebalance.com/art2_tennisone.html
I saw Federer play at the US Open a few years ago. The way he moves is very deceptive. He covers ground without seemingly trying to. Very smooth. Going up to net suddenly he's there. The decpetion is perhaps from a very stable, quiet upper body. It is not weaving and bobbing around as he runs forward. As we tend to focus more on the body than the legs it looks like he's gliding or not trying that hard but he gets there very quickly.