I was wondering how fast a pick moves for somebody playing 16th notes with the metronome set to 1/4 notes at 200bpm, and I think that the answer is around 2.4mph (peak). I was surprised that it is so slow, but it makes sense in retrospect. Somewhat interesting…
(I assumed that the pick’s position is like a sine wave with ±0.5" displacement, and asked google “2 pi (800/minute) (0.5 inch) in mph”, getting 2.4 mph, a comfortable walking speed.)
Interesting! Actually, I think it’s even lower than that since the frequency is 800/2 (the pick strikes the string twice every cycle).
Yes, you are right, HALF as fast, a mere 1.2mph! 
So how much acceleration does a pick have? This is a little bit more impressive, 2.3 times gravity.
So what this suggests to me is that people’s speeds are limited by their ability to turn the pick around—to change direction—and not by the actual speed of the pick. And I’m guessing that in this case the trick is not to have muscle groups fighting each other…
(This time I asked google “((2 * pi * 400/min)^2) (0.5 inch) / (9.8 m/s^2)”)
This is it! And at the biomechanical level, it’s the ability to alternate the opposing muscle groups rapidly, with power. I think it would help to look at picking speed not as “speed”, per se, because as you’re pointing out, most people already have the ability to move the pick as fast as it needs to go. It’s really frequency. The number of notes you can play per unit time depends on the frequency at which you can activate the muscles on one side of the movement, then the other side, and so on.
When you look at the fastest players, like @milehighshred and @TheCount, the pick spends almost no time accelerating and decelerating. Even though we know there is some brief instant where the pick’s velocity must be zero, at the fastest human speeds, that moment is so brief that the pick just looks like it’s moving back and forth at a constant speed. The sine wave becomes more sawtooth, at least in casual appearance:
If you feel that this also holds for regular fast players, it suggests a number of things:
So perhaps the mental model is (I am guessing here), “launch the hand and let it glide,” “launch the hand and let it glide,” etc., almost as if the hand is ballistic, like a rock that’s thrown back-and-forth?
In fact, even my “mental model” of the pick is interesting, I keep on thinking of the movement like a sine wave that needs to be meticulously controlled, but perhaps “bouncing back and forth at constant speed” is much better to avoid alternate muscle groups from fighting, and thereby making switching slow.
John calls it “jiggle” picking and says it feels like a controlled spasm. We have generally called it “hyperpicking”, thanks to an instructional video from the early 90s that is the first mention of it we are aware of. But this is a different type of motion from any that I do, and as far as we know, this technique only works with elbow motion. So I don’t mean to imply that however this motion functions when pushing 300bpm sixteenth notes is how other motions that use totally different joints also work.
Hells to the yeah! You remembered 
Ah, so it’s really a comment about how unique John is (and he is amazing, without doubt).
Now you have me wondering: Do slow people think like this (for a pick stroke)?
Do fast(er) people think like this?
the difference might not seem large, but I’ll bet it is, the second way is probably much faster to reverse. (No proof, just supposition.)
I still find it surreal to see my name along side ‘world’s fastest players!’ Haha!
As I mentioned to you all before, I never really practiced tremolo picking. Plenty of general speed picking, but the hyper picking thing was something I only really found out about when Troy labelled it as ‘absurdly fast.’
What I would be interested to see is if me and John simple stumbled on a way of making these muscles activate, or are we wired slightly differently?
I’ll leave that question for @Troy, since I have no idea. (Though if it does turn out we have mutant muscles, does that make us like an overly fast version of the X-Men? Haha!)
My bet is on “you’re doing it right and others (like me!) are not”. Mainly because of Occam’s Razor. In no way does this diminish your achievements - as in the case of all the players we interview, it takes a natural to figure out the optimal method for doing something, just so the rest of us dummies can eventually learn to do the same thing.
How can I forget the jiggle??
Ha! Well I certainly wouldn’t refer to you as a dummy! Glad my weird picking can be of use to someone anyway. Obviously let me know if there’s any other footage you want. Magnet is still primed and ready for use!
Personally, I focus on the rhythm. I don’t think in terms of start, start stop, momentum, etc. I just do my best to stay in time with whatever I want to play.