# How do powerful smash related to body weight?

Discussion in 'Techniques / Training' started by arfandy, Nov 5, 2014.

1. ### visor Regular Member

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Yonex uses KE, not F not P. Search for previous threads on this.

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2. ### captaincook Regular Member

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The math (rather the proof) can be worked out easily. You will need 2 equations - conversation of KE and converstation of P.
Start with a simple scenerio that only the wt of the racket counts - the wt of the racket m1 and shuttle m2, let v1r be the fixed speed of the racket upon hit the shuttle, v1s of shuttle starts at zero. Assume that this is an elastic collision, then calculate the v2 for both the racket and the shuttle after the collision (involves algebra, substitution, solving quad; hence the 2 equations and 2 unkowns).

Now the more realistic calculation, the wt of the racket is at least the arm+racket. With the same speed of v1r of the racket hitting the stationary shuttle, you will find the v2s of the shuttle is greater.

I would say that the "big" guy (heavy arm) is equivalent to a heavy racket, and the small guy (light arm) is equivalent to a light racket - both swinging at the same speed. The truth is, with kinetic chain, not only energy is transferred from leg up; the kicking of legs, the tightening of abs, grips, throwing motion all connecting the body mass to the racket - synchronizing as one.

Of course we know the collision is inelastic, the boom sound can be a lost of energy....

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3. ### Quentin11 Regular Member

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@rhoder

Interesting views here but it seems it remained unsolved.

If we do a comparison of smash of others MD players vs Praveen Jordan.

Why the slower smashes of Praveen looks so much more powerful than other faster smashes?

@visor anything on that?

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4. ### Ouchie Regular Member

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What is the difference between smash power and smash speed?

If you mean it looks like a fast smash but the shuttle speed is slower than you expect then the difference is the less elastic properties of the racket and string. More energy is lost to other things like sound and friction.

This thread covers it quite well. The body weight should not have a direct impact. It's the weight of the moving objects, from arm to racket that produce power. Bigger bodies could well be more muscular so can contribute more velocity to the arm and racket. So, redefine body weight at "well built, muscular" but it does not mean body builders can smash through walls.

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Last edited: Mar 20, 2020
5. ### seanc6441 Regular Member

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Surely if the shuttle or hall conditions isn't a variable here (same shuttle used and same hall each time) the power of the smash determines the shuttle speed. So fast is powerful and slow is less powerful always.

I'm guessing a smash that looks deceptively fast or slow compared to the power is simply because of the smashing technique being deceiving to our eyes. Remember our eyes tracking the smash and the shuttle so the racket action/smash technique plays a big part in our opinion of a smashes power.

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6. ### Budi Regular Member

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Considering he mean non pro that have no proper training, i think the reason why bulky mortal able to bit harder is coz they have more muscular body that help them to use heavier racket to produce powerfull smash. But i doubt the weight itself can add some power on stroke.

But 1 thing i notice is i see 2 different smash. Speed & power smash. Somehow for thing that i dont understand, some people smash is seems faster yet feel light on impact when i block it but some other people tho it seems slower but feel really heavy impact when blocking.

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7. ### Quentin11 Regular Member

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So are you saying that the powerful looking smash of Praveen Jordan is due to elastic properties of racket and string??

We all see how powerful the smash of Goh V Shem are and they are properly quick!

Praveen Jordan's smashes also look powerful but they aren't as fast at all! How? Why?

I understand that Goh V Shem smashes looks faster because they are more steep. Could it be the same reason for Praveen? Could be.

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8. ### seanc6441 Regular Member

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At the end of the day the only thing that matters is the speed of the shuttle at various points once it leaves the racket.

I don't see how one can distinguish between a powerful smash and a fast smash other than shuttle speed and time (time for the shuttle to leave the stringbed once hit) Angle is obviously important too. Less time to react if the shuttle is hitting the floor sooner.

Racket and string choice my come into play in the sense that some very stiff with harder strings rackets hold the shuttle on the string bed for slightly less time than a flexible racket with softer strings. Which may be perceived as faster or slower.

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9. ### Budi Regular Member

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im not sure how to explain what i feel but i measure speed by seeing it so some seems to feel faster than others.
Other hand i also feel the impact on my racket stringbed. Some feel light yet some feel heavy like the shuttle pushing the racket back.
& what i notice, faster smash seems lighter but slower one feel heavier.

Maybe it just my feeling or just my mind, idk how to explain it, so it can be true or might just be false.

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10. ### Cheung Moderator

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In native English, we would say some players have a 'heavy' smash.

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11. ### DarkHiatus Regular Member

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The only information carried by the shuttle is the shuttle's mass, speed, and trajectory - only the mass and speed can be adjusted by the smasher. Regardless of a player's build, a single speed and trajectory MUST behave the same when it hits the defenders racquet, assuming the defender's racquet is in the same position.

My feeling is there are several reasons to account for the 'heavy/power' smash Vs 'fast/light' smash, but all are summed up by the idea of consistency/control:
1. Perception of opponent - simply put, we do not expect a big smash from a smaller player. The reaction time is therefore slower and the shuttle often zips past because they played the shot already, and alternatively, because they are smaller, there is less psychological burden when you see you have given away an easy smash. This gives the effect of either not getting a shuttle, or being able more easily defend with control.
2. Racquet technique/preparation: larger players often have more compact movements, but are able still to impart a decent amount of force into the shuttle due to having large muscles - this is particularly apparent at amateur play where e.g. men often hit doubly as hard as women with even stick smashes (the gap closes in pro play). This means simply that larger players are genuinely hitting the shuttle harder than lighter players with less movement. Overall this is less reaction time. However, the rough direction is often more obvious, because the power is coming from the arm/shoulder rather than full body/pronation/grip tightening.
3. Finally, both of the above feed into the defender's control of the stroke. Against a 'heavy/power' smasher, we are likely to mistime/mishit the shuttle and lose a lot of control/power in our returns, even if we know the rough direction, simply because we have less time to react to the shuttle. Against a 'light/fast' smash, we are either less likely to get to the shuttle at all, or we still be better able to predict and defend the shuttle with control.
There are always 'outliers' which is why this informs my opinion. I have played against smaller players who I feel have 'heavy/power' smashes, and also against larger players who hit a lot of 'fast/light' smashes - I find the biggest difference is how deceptive and predictable they are overall as players. Deceptive players tend to have the fast/light style smashes that you just can't get to and predictable players have either light/fast smashes that are easier to return, or heavy smashes that are not (but I'm still able to retrieve them). Deceptive players aiming 'light/fast' smashes at the body can make them feel quite heavy indeed

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12. ### rhoder Regular Member

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The perceived “weight” of a shuttle can’t be due to kinetic energy/momentum of the shuttle, because with the same mass of the shuttle and similar speeds, the momentum/KE of the shuttle should be approximately the same. And it isn’t like Jordan has clocked a much faster smash speed.

Unless the weight experienced by the defender depends on something other than kinetic energy/momentum. Is that possible?

If not it has to be like the others have said, some placebo-like effect as a result of our perceptions.

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Last edited: Mar 20, 2020
13. ### ralphz Regular Member

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Is there a reason you and many people are only mentioning the mass of the arm and not the mass of the whole body?

Do you think the only mass that counts is the mass of the arm?

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14. ### ralphz Regular Member

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I'm no expert and the subject is clearly a bit speculative, but it seems to me that

Smashes that people may think of as Heavy are always loud and never a short swing. Often either a lot of body going into it, or, poor technique and a lot of arm. Always a very loud sound from the racket. Doesn't have to be a lot of mass but mass helps. A large person might not have such a strong arm or even significant body strength, but can get their weight coming forwards.

A beginner player that is not large, and with terrible inefficient badminton technique might even pull off a heavy clear. Not a short swing but not a large swing because they don't turn their body sideways enough for a long swing. And lots of arm power. And brushing it unintentionally big time because they aren't hitting through. But so much arm power that you hear a louder noise than when most clear it, and others may remark that the guy is hitting it so hard or that he has a lot of power, even though the speed of the shuttle may be typical for a clear.

Light smashes are short racket swing. A stick smash. Often can be steeper than a "heavy" one. I'd guess Body mass is irrelevant but maybe arm mass is.

Seems to me that a poor technique - stepping into it, even if somebody is not large , can lead to a heavy smash, as does a great scissors(is good technique, not stepping in). A large person might be able to get an even heavier smash and more power from their weight going into it eg if they do a scissor.

An interesting experiment would be a weight attached to arm and seeing effect on hitting it. Also a weighted backpack like an atlas pack maybe, or just weights in a heavy duty rucksack, would be an interesting experiment.

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15. ### Budi Regular Member

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i doubt an additional weight might add some power. Im muscleman myself 82kg 179cm, quite bulky myself.
With all my muscle 3U head heavy is pretty much light to me but all that in expense im not quite fast hand/swing. So having a lighter racket makes me struggle to swing faster. Other hand my friend did his best with lighter one but struggle with my racket. So i think the best optimum power is gain when one can balance his swing speed & his racket weight. Not to heavy to slow you down yet not to light to lose some momentum from the weight.

And again i live with this 82kg weight all day & night. My whole body used to my weight, so additional weight like carrying backpack wont give best result as you not used to it, so the balance & all will feel ackward & not naturally.

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16. ### Quentin11 Regular Member

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I think you are on to something ... the unexpected and short swing? Why i think so?

Lin Dan's stick smash looks more deadly than other players full smash even though it isn't as fast.

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17. ### regularAl New Member

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This is because he is left handed. Lefties have the advantage of adding natural spin to their smash, making this the fastest and most accurate shot in badminton. Right handed players can do it with their backhand, look up Praveen Jordan insane backhand drives for example.

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18. ### Ouchie Regular Member

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I should clarify that Praveen Jordan’s smash “could be” because of less elastic properties. He uses a pretty stiff racket but I don’t know what string or tension but when you can hit as hard as he does repulsion is not a priority. Additionally his smashes sound loud. The presence of sound is a sign of energy being lost. Again, some strings just make more sound than others and at different tones. A loud boom sounds more impressive compared to a loud ping but neither is a good indicator of outright speed.

The idea of powerful and fast being different is a nonsense when trying to use physics to explain smash speed. The words only make sense to an observers perception which is purely psychological. The observers sense of player muscles, effort, sound and even size of swing can all give an expectation.

Where some players smashes get slower over time as they tire it looks like PJ can smash hard for longer which must be very intimidating. Again another psychological effect in his favour. PJ also varies his smashes well so it makes it difficult to know where he will hit. He is just so intimidating that once opponents adapt to his style we will see some interesting battles.

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19. ### ralphz Regular Member

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Those numbers don't indicate much re muscle. Eg at what body fat (I would guess you never even checked)

Also you make such a big deal about muscular size but you don't say a word re strength.

What are the figures for your compound lifts(if any). And I guess you do some if you say you are a muscle man. Or maybe not. Maybe you think a "muscle man" can be any fat person walking cos they carry their own weight.

As for weighted backpacks and your suggestion about a person not being able to balance if they have additional weight. You should realise that when people squat with a barbell,balance is crucial and that a barbell adds "additional weight".

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20. ### yuquall Regular Member

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I think he would have called himself a "fat man" instead if he had so much body fat and little muscle in his body.

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