Why do people use a higher tension and get more power?

Discussion in 'Techniques / Training' started by xrawrhenry, Dec 26, 2009.

  1. LD rules!

    LD rules! Regular Member

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    any ideas As to how to train your wrist and machines or devieces I can purchase ? Thanks
     
  2. psychophant

    psychophant Regular Member

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    courtesy of BC's very own Mr. Paul Stewart :)

    http://www.youtube.com/watch?v=YLlYpja1nRo

    very simple but useful lesson.

    cheers!
     
  3. taneepak

    taneepak Regular Member

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    Lower tensions were used in the old days because the racquet frames then were mainly made of wood or aluminum, which besides not being able to be strung to high tensions without warping also did not have high enough youngs modulus to take advantage of very high tensions.
    In a way low tensions are a carry-over from the old days. Low tensions depend more on the resilience or stretching/compression of the stringbed to send the bird on its way.
    Today's carbon graphite racquets, which can range from low youngs modulus to ultra high modulus graphite, are very much stiffer than the old wooden or aluminum racquets. Unlike the old racquets whose frame will vibrate when hit at very high tensions due to the less rigid materials used, resulting in significant loss of energy, today's racquets of especially the very stiff ones like the Li Ning N series are best used at very high tensions. With very high tensions on frames that are super stiff-stiff as in youngs modulus-the stringbed at very high tensions and the racquet becomes a more lethal weapon because of its "oneness" instead of two separate pieces of frame + stringbed of the old days where the frame makes almost no contribution to power and high speed shots that we see today.
    This means that if you have very stiff or high youngs modulus racquets, then use high tensions to access their full potential. Of course they can be used at low tensions but this is not what very stiff or high modulus racquets are designed for.
     
  4. wristworks

    wristworks Regular Member

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    Higher tension generates more power if you're strong. Gollum correctly stated that if you were to start with a low tension and gradually move up, you'll find you generate more power up to a certain point. At that point, if you increase the tension more, you lose power.

    String tension works on a similar principle to shaft flexibility. Your string-bed is like a trampoline, pure and simple. When the shuttle makes contact with the string-bed, it bends the strings back. The strings then snap back into place, which propels the shuttle forwards. Like I said, exactly like a trampoline: you land on the trampoline, you bend the surface down, and then it springs you back up in order to regain its original shape.

    So let's say you start off at a neutral tension. We'll say 23 lbs. At the moment that you contact the bird, the force of your swing bends the strings back, let's say 2 cm. The strings then snap back into place and propels the bird forwards. So we'll use that as a standard.

    Then you increase your tension to say, 26 lbs. IF YOU ARE STRONG, then at the moment that you contact the bird, the force of your swing will still be able to bend the strings back 2 cm. Except now, because the tension is higher, the strings snap back into their original position at a faster speed and thus, increases the repulsion. Lo and behold, all the increased speed and repulsion translates to a more powerful smash.

    Wonderful. This increasing tension thing seems to be working. So now you decide to increase the tension to 30 lbs. Theoretically, it should work the same way. The higher tension should snap the strings back at an even faster speed and generate even more repulsion right? Well, that depends on your ability TO BEND THE STRINGS BACK 2 CM. If you are strong enough to bend the strings back 2 cm, then yes, you will create more power. However, if the tension has gotten so high that you can't even generate enough power to bend the strings back 2 cm, then the strings will only bend, say 1 cm (or less). In THIS scenario, then, yes, the strings will still snap back at a faster speed... but they're only snapping the distance of 1 cm, not 2. When that happens, you lose power (and you'll feel like you're hitting the shuttle with a wooden board).

    So you want to aim for an optimum balance right? You want to increase your tension as high as you can (for the increase in repulsion) WITHOUT compromising your ability to bend the strings. That's why professionals use super high tensions. THEY have the strength to bend the strings, even at comically high tensions. As a result, they reap the reward that is a more powerful and explosive smash. But if you don't have the strength to bend the strings, then you won't be able to reap the benefits of those same high tensions.
     
    #24 wristworks, Jan 6, 2010
    Last edited: Jan 6, 2010
  5. DivingBirdie

    DivingBirdie Regular Member

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    the physics explained in a simple manner---i think you nailed it
     
  6. scann

    scann Regular Member

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    Excellence explaination.

    My stringer allow to increase the tension by .5 lbs, so I am happy with 25.5lbs now.
     
  7. staiger

    staiger Regular Member

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    This is one of the best explanation on the string tension on this forum , someone should make it a sticky !
     
  8. t3tsubo

    t3tsubo Regular Member

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    You miss an important point in this explanation, which debunks the myth that higher tension gives you more power.

    Physically, there is no way correlation between string tension and the velocity that a badminton bird (or any object) leaves the racquet with the tension of the strings because energy must be conserved. A high string tension does not more waste energy to be created in the transfer of energy from the "swing" (input energy).
    However, you are correct in what you said because you specified that MORE input energy will be given in a higher tension racquet:
    Basically, i think you mislead a lot of people reading this because you didn't point out that it is not the string which is causing more power to in imparted, but you yourself. If you swing at the same speed or "power", you will NOT be able to bend the string back 2 cm like you were able to with the lower tension racquet and the resultant velocity will be the same. Your increased STRENGTH (to quote your own post) and the resultant increased SPEED of your swing causes the increased MOMENTUM of your racquet which causes the increased resultant velocity of the shuttleock.

    The laws of physics must be observed!

     
  9. cooler

    cooler Regular Member

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    The premise of high string tension + high racket speed to give big smash speed is too simplistic. It's somewhat true but in large part, not necessarily true. Big smashes aren't necessarily dependent on high tension string bed. People who use the tennis racket principle to say low tension string would yield more power(speed) from trampoline effect is also somewhat correct but in large part, not necessarily correct. The key driver to high shuttle speed generation is so simple, it is how fast u swing your racket using good old fashion muscle power + proper stroke technique. Making improvement on your racket speed is another topic and it's up to u and your coach to work on. However, i can give u real examples to support my claim. A BC member, Vining W., can launch shuttle bombs with a racket string tension of 17-19 lbs. Clearly his string bed isn't trampolining the shuttle out with rocket speed, it's his racket doing the job mostly, the string is there just to hold onto the shuttle. On the other extreme, Fu Haifung and TBH hold the top smashing speed record (i quoted these two players as fastest shuttle speed were tested under 2 different condition). I believe their racket string tension aren't the highest, right? I'm sure there are top pros out there that use higher tension than Fu HF and TBH but yet can not top current smash speed record holders.
     
  10. t3tsubo

    t3tsubo Regular Member

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    This has been scientifically disproved (i can link you to the journal where they did the experiment if you really want, unfortunately no such test has been done for a badminton racquet and shuttlecock). With all other variables the same (swing speed, point of impact, angle etc), the string tension does not affect the speed of the tennis ball.
     
  11. wristworks

    wristworks Regular Member

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    I said right from the get go that high string tension only increases power if you're strong so I don't know where all this misleading comes from. In fact, throughout the entire post, I made it a point to say that you have to be strong in order to properly utilize higher string tensions.

    What I am doing is illustrating the difference between having a low string tension vs. having a high string tension. As I said, if you are NOT strong, none of this will matter because you will only ever get power from a low tension. But I posit the assumption that, say you are a strong player. So let's say I'm a world class player. I'm pretty much as strong as you can get for a badminton player. Is there a difference in power between playing with a 19 lbs string tension vs. a 27 lbs string tension? Of course. Because your input will always remain constant: everyone smashes as hard as they can, regardless of string tension... you don't decide to "decrease" the amount of strength you put into your smash just because you have lower tension strings.

    So everyone's input will be relatively consistent, i.e. I will always use as much strength as I can when I smash, regardless of whether my tension is 19 or 27. So, as I said, let's assume I am a world class player. My input will always be consistently very high. With that consistent input, a racquet strung at 27 lbs will give me more power than a racquet strung at 19 lbs because 27 lbs will release energy FASTER after it's been loaded with potential energy. Sure, you can load the exact same amount of energy onto a racquet strung at 19 lbs. But because the tension is so much lower, the amount of time it takes for that potential energy to be released as kinetic energy is longer. As it stands, that increase in time already means that more energy is wasted. Furthermore, because the racquet is moving at such a fast speed, a lower tension means that the strings might not even be finished snapping before the shuttle leaves your racquet.

    If you want to really technical, the Conservation of Linear Momentum actually proves my point further. Momentum is retained in collisions, but KINETIC energy isn't. The more rigid two objects are, the more kinetic energy is retained (i.e. billiard balls and Newton's Cradle). If you had a case where 2 objects were perfectly rigid (only theoretically possible), then you would retain 100% of the kinetic energy. However, as the objects lose their rigidity, kinetic energy gets diffused. So for badminton, the lower the string tension, the more kinetic energy gets wasted.

    It's like throwing a deflated tennis ball against the ground with all your might vs. throwing a brand new tennis ball against the ground with all your might. The brand new ball bounces higher right? Same principle. Or compare throwing a tennis ball against a brick wall vs throwing it against a mattress.
     
    #31 wristworks, Jan 8, 2010
    Last edited: Jan 8, 2010
  12. t3tsubo

    t3tsubo Regular Member

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    I do agree with your point, but I just thought it wasn't clear that it was you and not your string tension that was causing a speed difference (since your post seemed to indicate that a speed difference existed with a change in string tension).
    the other gripe i had was when you said "optimum balance" in the end - which implies that different tension WOULD give you different resultant speeds, which does contradict what i thought. But your explanation of it
    that actually makes a lot of sense, and I hadn't gotten that technical in my thought experiment yet, since i was mostly comparing it with studies done for tennis which showed no difference. But you've changed my mind. That explanation is good.
     
    #32 t3tsubo, Jan 8, 2010
    Last edited: Jan 9, 2010
  13. cooler

    cooler Regular Member

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    You do that, go find that scientific journal.
    I do not believe a science paper will say in tennis, string tension has absolutely no effect on the exiting ball speed.
    Also, don't convince me as i said "but in large part, not necessarily correct". Convince this guy. http://www.badmintoncentral.com/forums/showpost.php?p=1310016&postcount=9
     
    #33 cooler, Jan 9, 2010
    Last edited: Jan 9, 2010
  14. cooler

    cooler Regular Member

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    u should clear up your technical thought before discrediting others base solely on some papers that u probably did not fully understood.
     
  15. t3tsubo

    t3tsubo Regular Member

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    Here's one

    I found another one which did show a difference, but it was opposite to badminton knowledge with the lower tension giving greater rebound speed.
     
  16. t3tsubo

    t3tsubo Regular Member

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    and here is another one where the experiment showed no effect
     
  17. t3tsubo

    t3tsubo Regular Member

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    Lets talk physics.
    After reading some of those articles, it seems to me that the main difference between badminton and tennis is the ball. In tennis the ball dissipates the energy because it deforms upon impact to a great degree. In badminton, the cork of the shuttle has to deform in order to compare the two results - and it doesn't deform anywhere near as much. If the string tension causes the amount of deformity, then it DOES impact the amount of waste energy created, which would change the speed.
    But for a badminton bird - would that not be negligibly small? Even the studies which showed a difference for tennis had to use 30lbs of difference to show a 3 km/h difference. A comparatively puny change of 5lbs in badminton while also taking into account how much less of a difference it will make to the deformity of cork rather than felt would make any change in velocity for a badminton bird caused by sting tension to be extremely small.
     
  18. cooler

    cooler Regular Member

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    after reading these two links, both supported my statements of post #29 which u try to say it's wrong. It is obvious u do not fully understood what the papers have said but had used it as a front to show how strong your hollow claims were.
     
  19. cooler

    cooler Regular Member

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    this paper talks about ball control. The effect of string tension on ball speed was not examined. Do u understand what ur reading?:rolleyes:
     
  20. cooler

    cooler Regular Member

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    i see u make your point with reference to a paper first and then u go read the paper afterward:rolleyes: Please firm up your understanding on this subject first before making more statements. Right now, u r just backpeddling.
     
    #40 cooler, Jan 9, 2010
    Last edited: Jan 9, 2010

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