Trying to lock in Reverse Dart Thrower as my primary picking motion, as it feels far and away the best on the table test and I can get some pretty good speeds going there.
On the guitar, it doesn’t feel quite as easy, not quite as fast either. But still pretty good. I can definitely see some tension building up and some elbow kicking in, but not sure how to eliminate that. Any advice is welcome!
The forum says it’s been a while, welcome back! You can submit technique critiques directly to Troy & Co for personalized feedback from the experts. Have you seen that feature on the main site (i.e. NOT the forum)?
One of the big differences between the tabletop test and the real thing is that the test has you moving horizontally, whereas it’s vertical on the guitar. The elbow can’t kick in horizontally (though the rotator cuff can), but it can definitely join in vertically.
The only way to stop it, in my experience, is… not to do it. 
Stay below the speed where it wants to kick in and see if you can learn to keep it quiet.
Thanks! Indeed it has.
I had not seen that, thank you!! Doing that now
Should’ve specified, I meant the motion I do first in the video- “picking” but on the surface of the desk instead of the guitar.
Regardless, it’s kicking in haha so I will try keeping the speed in check!
A few things to try:
Hard to tell, but are you slightly less supinated on the guitar? It kinda looks a touch more pronated (since there’s more of a gap / less pressure on your thumb heel to the table) and as such is using different muscle balances. I’m fairly sure we can do RDT with quite a supinated posture, so roll the forearm out a bit more towards supinated to make sure that’s not a contributing factor. You can reduce the angle again later, once the muscle memory has been developed.
Is the angle of the guitar too parallel to your body, where the butt of the guitar pushes your picking forearm forward? Or is your picking forearm/elbow losing bracing pressure against the guitar? Even with the guitar correctly diagonal to my body, I made some initial progress with a similar problem by gently pressing the picking forearm/elbow slightly more snugly against the the body of the guitar and moving the headstock away from me. Just a thought, to try briefly to reduce the arm lifting tension. Not a technique to squeeze the guitar hard.