We all know that most power comes from upper arm rotation + forearm pronation in smashes and clears. But i was wondering how much upper arm rotation is actually needed? In many technique videos step by step instructions the elbow raises unnaturally high (or at least it feels that way for me). Someone who understands this could explain it to me In conclusion my questions are:
1. How much upper arm rotation is needed for smashes and clears?
2. How high should the elbow raise during the rotation?
I can only speak for baseball and tennis because I'm new to badminton. basically this is the same overhead throwing motion. every throw starts with the upper arm in a neutral and bent position. then as the elbow accelerates forward and upward the lower arm lays back (upper arm externally rotates). then the elbow will decelerate and the arm rotation reverses into internal rotation (and arm extension). see this video: http://www.youtube.com/watch?v=wnPFSDTU_ng#t=1m53 also much of the elbow raise you see comes from shoulder tilt. the upper arm will not raise much higher than shoulder height but the shoulders tilt so that the elbow points up. the upper arm anatomically cannot raise much over the shoulder line. fu Haifeng might demonstrate lifting the elbow but it is not what he is actually doing because his shoulder would not survive that. any throw is basically a tilted sidearm throw, they will act in the shoulder line but tilt that line Uploaded with ImageShack.com
I know a lot about the overhead throw because I play baseball at a relatively good level. in baseball the overhead throw is studied a lot. actually one of the reasons I started to play badminton was to improve my conditioning, footwork and hand eye coordination for baseball (I'm a strong hitter but weak defender)
sorry last post was double. Also consider that upper arm IR and pronation don't happen at the same time. top hitters won't extend the arm and then use IR to support pronation in racket whipping. the IR will actually happen mostly while the arm is still bent so that it not only whips the racket but moves the hand forward/up in space (see the pitcher). the pronation then comes at the very end.