Can we talk about the physics of racket stiffness for a sec?

Discussion in 'Badminton Rackets / Equipment' started by LordGopu, Jul 11, 2017.

  1. LordGopu

    LordGopu Regular Member

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    I don't mean doing actual math (I have no idea how to calculate any of the things I'm going to post and I'm not asking anyone to put that much effort).

    The general knowledge that gets passed around is that

    flexible rackets = more power, less control
    stiffer rackets = more control, less power

    The control aspect I get. A stiffer, more solid frame should have less torque/flex that can mess with accuracy.

    It's the power aspect I'm unsure about. It seems to me that stiffer rackets should provide more power, in the same way that a stiffer bow/crossbow provides more power. Like bows are measured in draw weight (how much it takes to draw the bow) and higher draw weight bows are used for hunting bigger things. The harder it is to draw the bow, the more power is imparted on the arrow/bolt when you loose it.

    I'm not trying to compare bows and crossbows directly here, there's reasons for why crossbows usually have such high draw weights but that has nothing to do with badminton. I'm merely looking at the general idea that stiffer bow = more power. The bow is stiffer and therefore snaps back into its original shape faster than a more flexible bow.

    So it seems to me that a badminton racket would work the same. If you can flex an ultra-stiff shaft with your swing, then you should be able to generate more power than if you had a more flexible shaft. Assuming all other things are equal (racket weight, length, balance point, etc...).

    I tried to draw and 80lb bow once and I wasn't able to. Therefore I couldn't shoot the arrow. To me, this would be the equivalent of giving a ZFII to a newb. They can't swing properly and therefore cannot flex the stiff shaft of that racket. So because they don't have proper strength/technique to flex it, they can't get any of that sweet power out of it, just as I couldn't bend that 80lb. bow. But if they'd given me a 50lb. bow, I probably could have used it (like giving a newer player a more flexible racket).

    The weapon known as a blackjack/sap functions similarly as well, I think. It's a lead weight on the end of a tight spring wrapped in leather. When you swing it, the spring bends back, because of your swing speed and the head weight of the lead tip, and then all that energy is released at the moment of impact.

    Does this sound correct to anyone? I feel like flexible rackets are more forgiving and easy to use, but that a person should be using the stiffest racket they can bend with their swing in order to maximize control and power.

    Or am I missing some detail regarding the physics of how the bird is struck?
     
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  2. foo.tw

    foo.tw Regular Member

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    Less stiff rackets have higher energy efficiency at lower energy level.(passive situation)
    However, the total energy they can achieve at high energy level are not so good.(active situation)
    Also, less stiff rackets(frame) have hard time to generate high initial speed shots.

    As to control, it's more up to the design of the racket and technique of the owner.
    However, to design a flexible yet accurate racket is much more a challenge than a stiff one.
     
  3. LordGopu

    LordGopu Regular Member

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    How the hell have I never noticed that sticky? lol

    So it seems that what I posted is correct, no? That there is more potential energy in stiffer rackets? Because all pros use relatively short swings for most of their shots, no? In fact that video of the hardest smash ever recorded (not in a game, the player is like in a gym or something) has very little arm motion. It's almost all pronation.

    So is it fair to say that with correct technique you would probably benefit from a stiffer racket? Or, broadly speaking, the better you get the stiffer your rackets should be?
     
  4. ucantseeme

    ucantseeme Regular Member

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    IMO BC members should stop to find any correlations between equipment and level of play. They should also stop to find explainations for equipment-choices based on pros. Over the years I noticed that we have a lot of equipment scientists and sommeliers of equipment who can tell you in mm which BP will effect your game and which string gives you the best performance at which tension, without ever met you.

    FME there is no rule or scientific explainations who should use which string, racket, tension and who not. If you play alot at tournaments, you have often time to observe other players at your own level and below and above and you will always find a bunch of exceptions and reason why a player with a short swing, decent technique and aggressive play use a Nanoray Glanz and you will also find a defensive player who uses a VTZFII. People are different, likings are different and maybe it works for you and maybe not.
     
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  5. dave010

    dave010 Regular Member

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    I'd like to add that not everything can be measured in badminton. For example, my DZS and N99 weigh the same with identical balance point, but I would tell you the N99 is vastly superior. Ask someone else though, and they'd tell you the exact opposite. I play with both the 3U ZF2 and the N99 and enjoying both despite the huge differences in balance and flex. Instead of over analyzing things, pick the one that feels best to you and remember to have fun! :)
     
  6. Abu Tanki

    Abu Tanki Regular Member

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    I'd say what you've said are very good thoughts. Stiff rackets are more powerful if you have the technique to use them.

    Sent from my SM-J500FN using Tapatalk
     
  7. Maklike Tier

    Maklike Tier Regular Member

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    "I feel like flexible rackets are more forgiving and easy to use, but that a person should be using the stiffest racket they can bend with their swing in order to maximize control and power."

    This.
     
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  8. LordGopu

    LordGopu Regular Member

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    I agree that it's likely impossible to give specific balance points or exact tensions (beyond general advice like keep tensions near 20lbs for beginners, and go up from there as you feel comfortable). I absolutely agree that there's no way to know someone's exact needs.

    Although I agree that the best way is to experiment with different combinations of rackets, strings, etc..., the reality is that not everyone can do that (no rental places, limits as to what you can do with rentals ie. not changing the strings, whatever). It's also costly and time consuming to do things through trial an error. Being able to have a good starting point (like what rackets are recommended for different disciplines or level of play) can help narrow down your choices or at least point you in the right direction.

    My post was only about understanding how the racket types relate to power generation, especially since most information I see (other than that sticky topic above) makes it sound like stiffer rackets reduce your power but that might just stem from a misunderstanding of what is required of using a stiff racket.
     
  9. Charlie-SWUK

    Charlie-SWUK Regular Member

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    As @ucantseeme says, you can't always draw correlations to skill

    Something I will add is that, in my experience...
    A) Soft/flex rackets with a hard string bed feel very, very weird to use. They just don't feel right.
    B) Your strings and racket should work together, having a ZF2 with 20lbs is unlikely to have a synchronisation between string bending and racket flexing
    C) I find it painful to use very flexible rackets, because you'll feel that when they return to normal, they can go 'passed normal', and that adds strain.
     
  10. Maklike Tier

    Maklike Tier Regular Member

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    No, you were right in your first post. The 'power' in a racket depends largely on your ability to flex the shaft.

    However as with all systems, every part of it contributes so ultimately it comes down to how the racket 'system' works with your own physiology.

    The one caveat I will throw in there however is that the human body is highly adaptive, so given enough time it's possible to play well with almost anything. Will you be playing optimally? Probably not, but for many players it seems, playing with the same (or looks the same) racket as their heroes use is enough of a psychological edge to make up for any shortfalls.
     
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  11. LordGopu

    LordGopu Regular Member

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    I should hope by the time you're using a ZF2 you'd be at a reasonable string tension :p. I can't even play with 20lbs anymore. My shots go so far out it's ridiculous and my net shots bounce way too high. My old stringer screwed up my stringing job once and put like 20lbs when I asked for 24. I now have a new stringer lol.
     

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