I've read dozens of threads regarding smashes/wrist-usage/forearm pronation so I'm not getting into any of it. Forearm pronation is a given. That's what I use so this question assumes that as you swing, your racquet (as a right handed person) faces left, squares up the bird, and ends up more or less facing right. I haven't seen a thread that deals with this specific issue yet so I'm going to raise it. This might also largely depend on personal preference. From what I've seen there are 3 ways to smash using forearm pronation. 1. As you go through the motion, your grip should remain relatively stable throughout, perhaps being looser at the beginning, and tighter upon impact. 2. As you go through the motion, you start by gripping your racquet primarily using the ring and pinky finger and as you pronate your forearm, tighten up your thumb, index, and middle finger to generate power. 3. As you go through the motion, you start by gripping your racquet primarily using your thumb, index, and middle finger and as you pronate your forearm, tighten up your ring and pinky finger to generate power. All three as far as I know work to some degree (I've tried them all). I think method one gives more angle and perhaps more control. Is there a "proper" way to be smashing with forearm pronation? I've known various advanced players and coaches that use and teach it differently. Personal preference?
I also primarily use #3 but am certainly aware that the other variations are useful & have their advocates. Back in early 2005 there was a very good thread on the use of the fingers for smashing: badmintoncentral.com/forums/showthread.php?t=21018 In this thread, one of the variations was referred to as LBJ (Lee Jae Bok). (Starting) on page 2 of this thread, Lee Jae Bok (lbj707) himself provided considerable insight to the use of the fingers with his smash grip.
Have you ever heard of a force couple? Your fingers transfer forces from your arms to the racquet. The forces generated by your fingers on top are equal to the forces generated by your pinkie. It has to be so the racquet doesn't fall out of your hands. So what we have is two equal but opposite forces an equal but opposite distance from a point between. This results in a pure moment of rotation about that point.
power My power generation comes from my middle and ring finger, though my pinkie finger does add some force, I can generate big smashes when it is off the end of the racquet even. However when I hit my backhand, i do definately have more force being applied through my index finger and thumb