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Author Topic: Juggling dynamics  (Read 513 times)

Jeremy McCreary

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Juggling dynamics
« on: February 09, 2020, 04:54:00 PM »

Since many forum members are also into juggling, thought I'd share an interesting 2-page article in the latest issue of Physics Today...

Botvinick-Greenhouse, Jonah, and Shinbrot, Troy, 2020, Juggling dynamics, Physics Today, v. 73, p. 62; doi: 10.1063/PT.3.4417. I can view it online at https://doi.org/10.1063/PT.3.4417, but that link might only work for subscribers.

(You know you're a hopeless nerd when Physics Today is your favorite magazine.)

The central question: How can a speed-juggler catch a new ball every 120 ms when the reaction time of a highly trained human is 200 ms at best?

Short answer: Nobody knows for sure, but 2 features of our neurophysiology may help...
1. Our inner physicist: Human and monkey brains seem to be able to compute accurate parabolic trajectories from an internal representation of the relevant laws of motion.
2. Muscle memory.

Similar considerations may bear on advanced throwing top tricks, but there you have the added complication of string control. Hard to imagine that your inner physicist carries around equations of motion for something as physically perverse as flying string. :o
« Last Edit: February 09, 2020, 08:22:26 PM by Jeremy McCreary »
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ta0

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Re: Juggling dynamics
« Reply #1 on: February 10, 2020, 08:25:04 PM »

Thanks! Great articule! It is readable from that link without need to subscribe.
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the Earl of Whirl

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Re: Juggling dynamics
« Reply #2 on: February 10, 2020, 08:35:53 PM »

By speed juggler, I assume you are talking about someone doing seven balls or nine balls or more?!
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Jeremy McCreary

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Re: Juggling dynamics
« Reply #3 on: February 10, 2020, 10:38:36 PM »

By speed juggler, I assume you are talking about someone doing seven balls or nine balls or more?!

Sorry, article didn't say how many different balls in that context. Just stated that a speed-juggler can handle up to 500 catches / min, or 120 ms between catches.

Personally, I think they're asking the wrong question. Instead of how can any human possibly catch that fast, they ought to be asking people who can catch that fast what planets they're really from? And do they have any plans to eat us? :o
« Last Edit: February 10, 2020, 10:42:40 PM by Jeremy McCreary »
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the Earl of Whirl

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Re: Juggling dynamics
« Reply #4 on: February 10, 2020, 11:11:05 PM »

Personally, I do not think those numbers are right.....at least for what I would do with 5 balls.
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Jeremy McCreary

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Re: Juggling dynamics
« Reply #5 on: February 10, 2020, 11:55:25 PM »

Personally, I do not think those numbers are right.....at least for what I would do with 5 balls.

So, ballpark: How many catches / min can you do with 5 balls? And how many could the best 5-ball juggler you've ever seen do?
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mailman

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Re: Juggling dynamics
« Reply #6 on: February 12, 2020, 08:24:49 AM »

There's a guy in our juggling club that juggles NINE balls.  Now, that's FAST....
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the Earl of Whirl

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Re: Juggling dynamics
« Reply #7 on: February 12, 2020, 09:07:02 AM »

I looked back and tried to remember some of this information.  Generally speaking, I would have two throws from my right hand every second.  So, that was around 120 rights per minute or 240 total throws per minute.  In the earlier going it was more like 250 a minute but as I got better (and had slightly higher and more controlled throws) it was pretty consistent at 240 or slightly slower.  It became so consistent that if I did not have a watch going to time myself, I could figure out pretty quickly how long I had been juggling.  So you can see why I was so skeptical of that "speed juggling" number of 500.  Even with seven and nine balls, they are not that much faster than what I was doing.

But, after some research I found that "speed juggling" really was a challenge that people went after.  There is also a "slow juggling" challenge.  I totally missed all of this.  And guess what the speed juggling record is?  501 throw for one minute!!!  It seems that there are videos out there of both of these styles (I have not checked them out) and here is a link for that information complete with a graph: https://juggle.fandom.com/wiki/Speed_juggling
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John Buechele

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Re: Juggling dynamics
« Reply #8 on: February 13, 2020, 10:42:35 AM »

This caught my eye as I have played around with juggling at different speeds. Turns out the speed record of 501 is with 3 balls. If you watch the videos it also appears that the juggler doesn’t fully “catch” the ball, that is to say his fingers don’t close around the ball. I’m now intrigued by the possibilities.....
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Jeremy McCreary

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Re: Juggling dynamics
« Reply #9 on: February 13, 2020, 11:21:08 AM »

It seems that there are videos out there of both of these styles (I have not checked them out) and here is a link for that information complete with a graph: https://juggle.fandom.com/wiki/Speed_juggling

Great link! After watching the videos, I feel compelled to repeat myself...

Instead of how can any human possibly catch that fast, they ought to be asking people who can catch that fast what planets they're really from? And do they have any plans to eat us? :o

Pretty sure that Falco guy had more than 2 hands going at least some of the time.
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ta0

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Re: Juggling dynamics
« Reply #10 on: February 14, 2020, 10:01:13 AM »

Unfortunately, if you do a shower, the lower catch doesn't count. The same guy had 582 on that.
More impressive, on 4 ball (fountain) he got almost 500 (498) and would have gone well over if he could have maintained the pace of the first 30 seconds.
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