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Body kinetics for power strokes

Discussion in 'Techniques / Training' started by Phil, Aug 16, 2003.

  1. Phil

    Phil Regular Member

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    This past week I was at Brantford for the summer badminton camp, and on one of the evenings, there was a presentation for the coaches and anyone who wanted to watch at the camp coordinator's house. This presentation was on badminton power strokes, the clear, backhand clear, and the smash.

    Of the two making the presentation, one was I believe and kinetics researcher, the other a biomechanist. They are the only ones who have done any research in badminton relating to how the body works, and the presentation was based on over 30 years of research. They had already done countless presentations around the world and at IBF technical meetings and whatnot. Video footage of a player in a lab at 400 frames per second was used, and apparently Great Britain and Germany have tried buying it, but they will not sell it to them. Slow-motion footage of some international tournaments and players was used as well. They had two cameras that cost $17,000 CAD each and they payed for but themselves to do the research because of lack of funding.

    Some of us (players at the camp) were out go-karting that night, so when we got back we had missed the part on the forehand clear and smash, but we came in right as he was starting to explain the backhand shot.

    Anyways, here are some points that I learned from the presentation in no particular order (not all were new to me, and I'm sure many here will already be familiar with them):
    (the presenters were Dave Waddell and a lady I can't remember her name, both looked at least in their 60's)

    - pronation or supination of the forearm is the final motion in a power shot, and combined with shoulder rotation are VERY important to power
    - there is no such thing as "wrist snap" for a power shot; a smash takes 1/10th of a second, there is no time to "snap your wrist" as many coaches teach; doing wrist curls to strengthen your forearm is USELESS for increasing power, exercises that work the pronation and supination of the forearm are what works
    - pronation/supination combined with shoulder rotation contributes to about 30% of the power in a power stroke
    - joint-action motion is very important; I believe this is what someone was talking about before in a post called "questioning the kinetic link"; e.g. your legs rotate then stop then your hips rotate and stop then you upper body, etc. until finally your forearm and racquet finishes the motion like the cracking of a whip
    - every smash is a jump smash, your feet always leave the ground if you are using body rotation
    - if you watch someone smash and their racquet finishes with the racquet face facing down, they are losing power; so if you were watching from the side you would see the side of the racquet head; the racquet head should be making a 180 degree turn from the beginning of the stroke through pronation/supination through to the follow through; same with backhand, the follow through should see the racquet face facing sideways
    - if you watch a proper backhand stroke in slow motion, you will see that it is a reflection of a forehand power stroke, with the exception being the elbow preparation, was very cool watching the slow motion video capture of a backhand in reverse and it looked just like a forehand stroke
    - elbow is important for preparation in a stroke; for backhand, lower elbow and have forearm closer to body right before the stroke to put pressure on the muscles; same for forehand power strokes, with elbow pulled back; it is important that with this elbow/arm preparation that there is no pause between when the elbow is lowered/pulled back and when the stroke commences, other wise the pressure on the muscle would have been wasted; so don't pull down/back your elbow too early, or it will be wasted
    - the ideal angle of the elbow between the forearm and upper arm for a power stroke is between 90deg and 135deg; any less than 90 is loss of power because to close to your body, vice-versa for over 135deg extension of arm
    - continuing the previous point, reaching "as high as you can" for a shot as many coaches teach is not efficient and loses alot of power; as well, doing this for a backhand shot can lead to hyperextension of the elbow

    I'm sure there was more, but I lost my paper that I wrote everything down on! :eek:

    So basically, don't do wrist curls if you want to increase your power, it is useless because it is the pronation or supination of the forearm that is very important to power, as there is no "wrist snap." Much easier to understand with the video aids.

    Phil
     
  2. Ashish

    Ashish Regular Member

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    whao these guys have done their homework
     
  3. Californian

    Californian Regular Member

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    This kind of technical work always fascinates me. There is so much more research that could be done, but there is so little financial reward in it.

    These presenters should put their work into a video presentation and offer it for sale. Thanks for the post, Phil.
     
  4. Nanashi

    Nanashi Regular Member

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    this might be why they haven't put a price cali! =)
     
  5. ruth1

    ruth1 Regular Member

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    that sounds like a cool session to sit on in. did they happen to mention what exercises for the pronation/supination would be most beneficial?
     
  6. Californian

    Californian Regular Member

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    I can understand why they don't want to package their presentation for sale. Once they make it available like that, they lose control of what happens to it. I'm wondering if they have published anything in journals or book form.

    From the little bit of searching I did, I see that Dave Waddell seems to be a significant name in Canadian badminton. Obviously, he must have an office or some way to be contacted about arranging a presentation. This is something I think many of us would like to go to if we knew where it would be held, and if we could get in to it.
     
  7. teddy

    teddy Regular Member

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    Does that means anything improving your wirst power is of no use because it is not used in generating power?
     
  8. birdieman

    birdieman Regular Member

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    i thought pronation was the rotation of the forearm 90 degrees to meet the shuttle with a flat raquet face so you don't slice/cut and lose power. and the wrist snap was to direct the shuttle downwards and increases your power.
     
  9. Californian

    Californian Regular Member

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    In a full 180 deg. pronation, you rotate the racquet head 90 degrees, contact the shuttle with the flat face, and continue the rotation for another 90. Obviously, the timing is critical for accuracy.
     
    #9 Californian, Aug 17, 2003
    Last edited: Aug 17, 2003
  10. cooler

    cooler Regular Member

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    A tennis serve is almost 100% identical to a badminton smash. Forearm and upper arm rotation is used extensively. I have seen photos of anna kournivkova and arbi H. and peter gade arms as full cocked positon, they look identical. That's how i come to think more fore/upper arms rotation would add to my smash. I have tried exerting more forearm and upperarm rotations from advice also given in previous BF posts(2002?) and had given me more raw power but with less accuracy when compared to my regular smash. I'm sure accuracy would improve with practice. However, the full power smash is very energy demanding and is a trade off to quick release smash in quicker rallies.


    on a side note, a friend told me arbi Heriyanto is coaching the US national team, is this true?
     
    #10 cooler, Aug 17, 2003
    Last edited: Aug 17, 2003
  11. My99broke

    My99broke Regular Member

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    also, while you are waiting for the shuttle in a forehand stroke, its also very important to have your wrist cocked up so that you can turn the full 90 (or 180?) degrees to pronate. When you look at your racquet behind you the face should be pointing in the general upward direction, this is also a key factor to pronate properly.
     
  12. Phil

    Phil Regular Member

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    They didn't go specifically into exercises, although on the side the lady was showing someone one that uses a rubber band type thing held in the hand and the other end underneath the foot while sitting. Hole forearms out parallel to ground and rotate them. I wasn't paying much attention to that because she was showing someone else.

    However, an on-court exercise that was stressed was to have two players just hit back and forth standing flat-footed using only shoulder rotation and wrist pronation. The players can eventually start hitting from farther and farther apart, even in the first session as they learn to use these two body movements effectively. The same can be done for backhand.

    According to the researcher's, wrist snap is pretty much a myth for full power strokes. Of course, you should be using a snapping stroke for net kills, etc. Watch a slow-motion video of a good international player, and you will see the full pronation.

    I've attached a picture of Shon Seung Mo and you can see that his forearm has almost fully pronated.

    I'm going to be away for a few days, so I won't be able to answer any questions quickly.

    Phil
     
    #12 Phil, Aug 18, 2003
    Last edited: Aug 18, 2003
  13. Phil

    Phil Regular Member

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    ...
     

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  14. Phil

    Phil Regular Member

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    Here is another really good one of Bao Chunlai. You can tell that even though he was hitting a tough shot from behind his body, he has still pronated, and the picture has a realy good angle to show it.
     

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  15. kwun

    kwun Administrator

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    following this thread with great interests.

    two points that especially caught my eyes.

    one is the backhand being reflection of forehand. after learning of this fact, i went to the gym and did some backhand trying to focus more on using pronation for power. i can't say i got it completely, but i noticed the combination of a relaxed grip and some pronation is really adding a lot of power to the stroke.

    i deliberately try to imitate the forehand''s pronation (mirrored), so my preparation had the back of my palm facing me, and then rotate during the stroke, at the end of the stroke, the back of the palm is facing outwards.

    this is the exact opposite of forehand, where the palm is facing me on recoil, and then wrist pronates and at the end of the forehand, the palm is facing outwards.

    it took me a few shots to get the timing correct. i noticed that i need more body movement with the pronation added. in particular, i need to rotate my body clockwise more during impact to compensate the extra pronation. this is again, mirror of forehand.
     
    ainchekar likes this.
  16. kwun

    kwun Administrator

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    the other point that was interesting is that the researcher seems to claim that flexion has 0% contribution to power in a smash. while conceivable, i am sceptical of these black/white claims. perhaps pronation contribute more than flexion, but surely flexion have some contribution? may be 10%?

    the wrist/forearm/arm is such a complex structure i am still having trouble trying to figure out how the whole thing goes during the stroke.
     
  17. Neil Nicholls

    Neil Nicholls Regular Member

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    Is that all ??
    Where does the rest come from ? Can it all be from the whip action ?


    Kwun,
    I've been trying to make my backhand clear the same as my forehand (but in reverse) for quite a while now. I don't think you need much (if any) body rotation.
    Where you make contact with the shuttle is important.
    If you are standing (or have lunged) such that you have your back to the net, you want the shuttle to be in pretty much the same place as for a forehand smash.
    In front of you (further away from the net than you are).
    If you try to hit it behind you, the racquet head will be decelerating by the time you hit it.
     
  18. Cheung

    Cheung Moderator

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    the rotation for 'overhead' backhand is called supination. I hesitate o call it overhead becuase the striking point isn't always over the shoulder.
     
  19. Pete LSD

    Pete LSD Regular Member

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    I agree that the overhead backhand doesn't always have an above shoulder striking point. Technically backhand overhead is supination of the forearm - an outside-in rotation along the forearm axis.

     
  20. Phil

    Phil Regular Member

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    I'm back for a day, gonna be for about a week after this post.

    They said that wrist flexion has pretty much no value at all... I lost my papers with the info on it but hopefully my friend can send it to me soon. Remember that this is in regards to power strokes. He emphasized that there is no time to "flick the wrist down" in a smash because it takes so little time to complete the whole stroke.

    Another thing that contributed to power was the angle between the upper arm and forearm (elbow joint) and the angle between forearm and racquet (wrist). This is why you should not fully extend your arm for power strokes. I wasn't there for the main explanation or physics of it.

    One more point I remember now before I have to go, for drives on the forehand side where the racquet head is above the waist, pronation is used, while for forehand drives below the waist, supination is used. Vice-versa for backhand drives; supination for above waist drives, pronation for below waist drives.

    Hopefully I can get my info back and get more information.

    Phil
     

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