OK. Question 1: All objects, whether stationary or in motion, resist being moved. Hand bones are objects. So if hands are moving in one direction, they resist any effort to move them in another direction. The same law applies to every bone in your body and to anything that you are holding, like a golf club. The same law applies to a planet. If hands are attached via a passive flexible wrist joint to your arms, then they will want to stay where they are when any movement of the bigger arms occurs. This phenomena will keep hands in the condition they are, fully flexed at the wrist and already lagging the arm bones, or cause them to flex and then trail or lag the arm bones. This lagging condition of the hands will remain as long as the arms keep accelerating. But if you decide to use the hands muscularly, you will contract the flexor muscles in your forearms to flex the wrists/hands so that you can then contract the extensor muscles to extend the wrists/hands in order to actually do something with your hands, i.e., put them to work! You can simultaneously do the same with forearms, upper arms, hips, legs, feet, etc. Its similar to pushing a child on a swing. In that scenario, most humans will muscularly flex their hands and elbows in order to muscularly extend them to propel the child/swing.
All I'm saying is that I prefer hands to be muscularly active to help produce good golf swings, and both of them can work together to form a remarkable force couplet. I prefer that the right hand flexes and extends much like a good basketball player's free throw or a good rock skipper's rock skip. I prefer that the left hand perform like it would if you turn a Frisbee upside down and place your left thumb flush against the flat of the rim while the narrow edge of the rim is flush against the inside of your forearm. Fling that upside down Frisbee and I guarantee that your left wrist will muscularly hinge and unhinge to create the best fling, just as your right wrist would muscularly hinge and unhinge, though in a different way, to skip a good rock. Do either of these activities and you may not need written arguments to convince you that muscularly active wrists can be a huge advantage when used well.
Question 2: I hope answer 1 suffices here. To slam a door you will likely flex your dominant hand and elbow to then overcome the door's resistance to being slammed, and then you will muscularly extend those bones to get the job done. Very similar to what right arm and hand do in good golf swing.
Question 3: Question 1 answer should also answer this one. You must contract muscles to move bones in one direction, be they little or big bones. Then you must use opposing muscles to flex and contract to move these big or little bones in another direction. You must go through the same process to move every bone even though different muscles are used per each bone, and you can decide not to move a bone or a set of bones in favor of others.
This is another stream of consciousness blurt, so excuse the English. I've been arguing to use appropriate muscular force to move the right arm and forearm, left arm, and both hands to execute good, if not best, downswings for years. The only credible folks to agree with me in a public forum (Tomasello, Vardon, Armour, Jacobs, if they were alive, might agree), are Dr. Zick and Brian Manzella in his own unique way. The Manzella teacher who advocates the basketball jump shot downswing in a recent PGA magazine article I think would agree. Anyhow I'm done with it. I'll only argue face to face here on out. Thank you.
