I don't see how that can cause any significant pronation. It must be relying on the rackets inertia? Because it doesnt seem like it will cause any tension in the muscles to do with pronation...
Read what khoai said, he's got it spot on. That's correct, and the inertia of your forearm. That's why they say the stronger you are, the heavier the racket you use.
For only 9 posts, you demonstrate an excellent understanding of what kenzo is saying! Especially the last sentence in bold.
What kenzo is saying re eccentric contraction of muscles is really about prestretching or preloading the muscle fibres just before concentric contraction in order to maximize power and speed from the muscle fibres. That is how the split step in badminton works for your thigh and calf muscles. That is how it works for Olympic weight-lifters when they allow the weight to drop a bit before actually lifting it.
so it's nothing to do with the shoulder then you start to pronate, then when pronation has some momentum, you start suppination. thats all bicep/tricep/forearm - nothing to do with the shoulder!
That's like saying your legs have nothing to do with your smash. Try smashing with no legs. Go on, I dare you.
btw, kenzo, how do you know so much about human physiology and kinesiology? are you a physiotherapist or kinesiologist?
no, it's not at all. My original question is about how pronation can be eccentric - your explanation was 'its the shoulder from backswing'. Which I just vehemently disagreed with. you are continually moving goal posts and attempting to baffle with ********. well, it aint washing with me. The saying 'a little knowledge is a dangerous thing' seems quite apt here. You clearly have some knowledge and adept in at least some technical language, but when questioned on specifics you deflect and can't give accurate answers. It appears that you don't know where the limits of your knowledge are, and wont admit to as much when posed questions that it is apparant you can't adequately answer. adieu.
Haha. No, firstly I explained how a pronation can be eccentric. Then you were confused about how the pronation is eccentric in a backswing for a backhand shot and what external force acts upon the elbow join in order to cause eccentric pronation, to which I said the shoulder. You could explain why that makes no sense to you, but I guess you'd rather play ring a ring o' roses with me. The full explanation of the backswing is to do with proximal-distal sequences, but I don't think explaining it will help your confusion.
amletto, for someone who is trying to learn from another person, being a bit less antagonistic would be helpful... what kenzo is trying to explain to you (which you have to admit is no easy task on a forum without visual aids or pictures), is that the weight of the racket, hand and arm will stretch (ie. eccentric contract) the supinators on the relaxed backswing just simply from gravity acting the arm. Just like the pronators are eccentrically contracted ie stretched on the relaxed backswing for the forehand smash. noticed i said relaxed, because only then can the muscle fibres be preloaded
Maybe I should properly explain so that there's no possible chance of confusion. The way you think you understand it at the moment is that you can give your arm some momentum by pronating concentrically and then relaxing your arm and letting it pronate further eccentrically, and then supinating concentrically. While it's true yes, that you can do this, it does not produce the racket head speed needed to hit a backhand clear. Why? Because this method does not produce enough power in order to sufficiently eccentrically pronate. So how do you produce the power needed to sufficiently eccentrically pronate? Well that's easy, through a backswing generated by power from other parts of your body, which you then transfer to your forearm through a proximal-distal sequence known colloquially as the whipping motion. Oh, another question you could ask is why can't you pronate concentrically to add to the power? Because you don't have time in a proximal-distal sequence. By the time you pronate concentrically, the power you've generated would have dissipated.
So if I understand rightly, you shouldn't try to pronate, it should just happen as a side effect of your arm action? Are you sure "backswing" is the right word? I thought the pronation happened at the start of the forwards movement, as the elbow comes up.
Just as you don't forcibly try to supinate winding up in preparation for pronation in the forehand power stroke, you also don't forcibly try to pronate before supinating in the backhand power stroke. That's why the arm should feel relaxed in the backswing in both types of strokes, otherwise it is difficult to properly transfer the "proximal to distal" forces of the whipping motion that kenzo refers to, ie. from the legs to hips to core to shoulder to arm to forearm to fingers to handle to racket head. As to the second part of your question, as you turn your chest away from the net in preparation for the backhand, you'll notice your hand and racket go towards the backcourt while pronating in a relaxed fashion even before your elbow starts going forward. That is the backswing.
Hi visor, thanks for the reply... Sorry, I'm not getting this. Looking at the video (first post of this thread), if you pause between 1:58 and 2:00, you'll see that the side of the racket that's going to hit the shuttle is facing outwards (away from the player). It looks as though the forearm is pretty much in a neutral position, neither pronated nor supinated. I don't see the pronation happening until 2:01 when the elbow comes up. Am I missing something here?
look at 2:17 to 2:20 slow mo there is a very short and quick drop of the hand and racket head along with very quick pronation on the backswing... just before the elbow leads upwards on the forward swing. that right there is a very quick eccentric contraction that kenzo refers to
@thejym, after looking at the video again, it looks like you missed something important... like the backhand clear and the backhand smash! seriously, those were only half court shots, drops and slices...but not clears nor smashes as your title suggests
It's not just the side effect of your arm action, it's the whole purpose of a "backswing". A backswing is just a term used to describe the motion leading up to the final pronation/supination. In the correct backswing for a backhand clear, you shouldn't try to pronate concentrically as you said. This is commonly referred to by people saying you should relax during a backhand clear. Also never enough backhand smashing
No, it is at 2.11 - 2.12 that when the pronation happened and yes if my understanding is correct it is not a forced (concentric) contraction as it is in a relax state. I think we are going too deep with physio-kinetical stuff even it is very interesting ,can we use simpler term so everyone on the forum could understand. the backhand smash and the clear is already covered in the end of the video , once you got the basic technique then it is down to you to interpret it and add some implementation. ---he is not going to hold your hand and teach you the exact way of how he hit his backhand smash.
Well it's needed to explain why you do the things you do to hit a backhand clear. It's very easy to explain footwork, why you do a split step and position your feet the way you do, why you land heel first and slide your non dominant foot in when you lunge, etc etc. But when anyone asks why you do the shots the way you do, no one ever seems to come up with a good enough or convincing reason except for, that's how you are supposed to do it, or that's how the pros do it, or that's how you generate power. All the coaching cues and jargon used to describe what you should do in order to produce the same shot just really disguise what is actually happening. There has been so much research done to figure out what exactly happens in motions too quick for the eye to see, and most of it goes unnoticed because there is a huge lack of interest, when all it takes is a simple google search. When you understand how something works, it's a lot easier to learn how to do it. Coaching cues are very useful when it's not practical to explain what is really happening, but on a forum you don't have this problem. For a backhand clear, most of the time all you are lacking is a bit of strength in supination to do the correct technique, and if you understand what the correct technique is, then you can simply train to increase your supination strength by using a heavy racket and practicing the correct technique focusing on supination snap or any other preferred method.
