Maybe replace image of "strong" with "tonus optimus" or functional tension, just enough, and dynamically adjusting as needed.
To orig-Q: Yes, the stable mass of upper body (via it's momentum) allows the lighter feet to be active and agile. The smoother the path of the body the more active the feet can be (watch WC Slalom racers & mogul skiers). If you are moving the upper body around un-necesarily, one or both feet need to anchor to provide a leverage point from which to do so. Excessice arm movements (at 35-50# each) also have an inhibiting effect on agility, and balance as well.
On chi, I use a concept of "grounding" one's weight, or "settling". Bud Cook called it "weight underside" in an Akido workshop at the '80 Nat. Academy. It is the opposite of always pushing up and creating extra verticle tension in the body in unnatural conflict with gravity. One of my favorites is from Denise McCluggage's Center Skier where she talks about "grooving with gravity". I think of skiing as a "gravitational dance" where when we try to cause what we should allow, we only muck up the flow.
<FONT COLOR="#800080" SIZE="1">[ January 12, 2002 08:09 AM: Message edited 2 times, by Arcmeister ]</font>