Debunking implausible gravity claims in pianism/boxing

[Andrew Thayer]

Perhaps one day some clever engineer will invent a machine that turns downward speed into horizontal speed.

I did think that a pole vaulter manages to turn horizontal speed into vertical speed.

It's funny, though, that that is possible but not the other way round.

Perhaps if the vaulter landed on an angled trampoline, that would fire him forward, turning his downward speed into horizontal speed again. That would be bizarre!

It's perfectly possible in demspey's sledge example. I'm just baffled by how it can be done to any meaningful degree in a punch.

 

[PeroK]

It's perfectly possible in demspey's sledge example. I'm just baffled by how it can be done to any meaningful degree in a punch.

Actually, I just remembered something I heard recently. I was watching the tennis and heard a tip on volleying at the net. You take a little jump. You have to time the jump, so that you land just as your opponent is hitting the shot, and you have to make a decision whether to move left or right. The little jump allows you to spring left or right faster than from a normal standing position.

Perhaps that's just more sports pseudo science!

 

[Andrew Thayer]

Actually, I just remembered something I heard recently. I was watching the tennis and heard a tip on volleying at the net. You take a little jump. You have to time the jump, so that you land just as your opponent is hitting the shot, and you have to make a decision whether to move left or right. The little jump allows you to spring left or right faster than from a normal standing position.

Perhaps that's just more sports pseudo science!

Sounds more credible to me. Leaning doesn't generate phenomenal speed, but it certainly prepares you to move. There's some bizarre running method called the falling rod. The idea is that you "fall" forwards continuously like a leaning rod on your hand that balances as long as as you keep moving. Obviously it's untrue and you don't actually fall. The sense you're about o fall just keeps you pushing on, to stop you falling.

I heard a theory from feldenkrais that we evolved to two feet because you're ready to lean in any direction and instantly start moving that way. It doesn't work on all fours. Probably impossible to prove but an interesting idea. Creating instability by leaning slightly with gravity is certainly an excellent way to trigger powerful movement (even if dubious when portrayed as a power source, rather than a trigger).

 

[A.T.]

You're blaming our physiology

For setting the limit on how fast humans can move? Of course.

but there's no evidence it can be done faster without that variable.

Are seriously doubting that a machine could do it faster?

 

[Andrew Thayer]

For setting the limit on how fast humans can move? Of course.Are seriously doubting that a machine could do it faster?

Yes, I'm doubting it would be a whole lot faster when limited to waiting for gravity to both decelerate the upward part and generate the whole downward part.
My muscles are radically quicker than gravity. I can whip an arm up even directly against gravity far quicker than it will fall. Looking at the true amplitude of octave playing, we really ought to be doing calculations for at least three centimeters of movement, rather than the one cm I originally gave for key movement. I don't think it's unreasonable to think that I might perform faster under muscular reversal than a machine that is limited to upward acceleration alone. Take a look at the speed of Argerich's octaves. I don't believe a machine could reach that speed without active downward impulses. I don't doubt in the least that she's faster than a machine that is powerless in any direction other than up. It's only through ACTIVE downward acceleration beyond gravity that a machine becomes superior to a human.

 

[Andrew Thayer]

A human who limits themself to gravitational acceleration hasn't even neared their physiological limit. It would be quite such a handicap to human and machine alike that I wouldn't expect a remotely impressive frequency from either. If the machine alone has the handicap and I use my muscles, I'm sure I could beat it.

 

[berkeman]

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