Boogar, this made me laugh. In English the term "underarm" refers to the hollow between the upper arm and the torso. The part that starts growing hair when you reach puberty, the part where you apply underarm deodorant. It is also referred to as "the armpit"!
The part of the arm you are referring to is called the FOREARM. [emoji2]
All good.
But I will show the video Siva is talking about.
The pivot from the elbow that causes the forearm to rotate in that motion IS IN FACT Shoulder Rotation.
The other movement in the video which shows what you shouldn't do IS CALLED Shoulder Extension.
So the rotation does in fact come from the shoulder. But that rotation should not stress your shoulder.
And, the simple FACT OF THE MATTER IS, the shoulder pain Siva is experiencing is coming from the bad mechanics we have been talking about in his strokes!!!!
That is the big difference between efficiency and inefficiency, functional movements and dysfunctional movements.
Why did Siva not feel the shoulder problems before with the bad mechanics he clearly has? The old rubbers, with their springy sponge, did so much more of the work of the strokes for him, that he didn't notice the effects of those dysfunctional movements on his shoulder joints.
With tacky rubber, your technique must be excellent for you to be able to utilize their full potential; this is because the sponge does not help you unless you have enough impact and your technique is very CLEAN.
And Siva's strokes are fundamentally flawed despite his ability to play at a decent level. He has been able to have bad strokes and get decent shots for HIS level. But his strokes are not what causes him to be his level. In fact, I would put money on it, that, guys who he plays 50/50 with, guys who he plays and wins half the time, and loses half the time, after they get past his serves, they are much better than him at most other aspects of the game. But, Siva's serves ARE darn good. So that is okay.
BTW: I am not saying that there is anything wrong with Siva when I say his strokes are fundamentally flawed. Siva is a self taught player. And he has learned many things by watching players on Internet videos, misunderstanding what he is seeing and not realizing he is doing something different than what he thinks he is doing.
But he is quite capable of fixing those fundamental flaws which are actually holding him back. When he fixes them, his overall technique and his level of play will skyrocket. Because he still has something special. And that is touch.
But Siva's upper arm moves in SHOULDER EXTENSION way too much in both FH and BH strokes for the safety of his shoulder joint. And that motion on his FH where the elbow raises higher than the racket, like what Samason Dubina imitates as NOT WHAT YOU WANT, in the video below, that is downright BAD--like DANGER Will Robinson--to the health of your shoulder joint. And I actually have a feeling that that motion on his FH actually contributed to the pain Siva began to feel when he was making his BH shots.
I hope this helps Siva.
Watch this video of Samson Dubina over and over again and try and duplicate that kind of FH. Try and make the BH come from the pivot on the elbow too. When you can isolate the movement of the forearm and make it so that the upper arm does not move forward and back during your stroke, then you can let the upper arm start moving some. Then at some point doing a fuller arm movement on big strokes will be okay. But that won't happen until you can pivot from the elbow on both FH and BH strokes because there is too much going on with your strokes that needs changing as of now. And now you know that those strokes are hazardous to the health of your shoulder.
At 1:50 in following video, Ariel Hsing is strapping her arm to her side. The interviewer asks: "What's that?" Her answer is: "Forehand Fixing Machine!!!!!!" See if you can figure out why.
Sent from Deep Space by Abacus