Pretty self-explanatory title: when wrist picking, every time I try to upstroke, my thumb joint closest to my hand extends. I simply cannot figure out a way of picking straight through the strings without doing that. The only alternative seems to be moving my hand awkwardly towards the bridge. Maybe it’s supposed to do that?
Any thoughts?
I used athletes tape in order to tape my thumb to keep it straight. I did it in order to experiment without having to relearn my motion mechanic. I ended up being ok with some thumb movement (at least for now).
[https://photos.google.com/photo/AF1QipMtuB6lOmRzeizXW1CKc4SKyQGMto-qYu-ja77o]
https://photos.google.com/photo/AF1QipMtuB6lOmRzeizXW1CKc4SKyQGMto-qYu-ja77o
Here’s what I mean. I have to add an awkward hand movement (0:07) in order to not move my thumb
Is Andy using thumb movement here in the same way? Looks like he might be.
Does it cause any discomfort / tonal or timing issues? If not I would not worry too much!
A little bit of discomfort, definitely consistency issues. Do you move the thumb? I don’t really know how not to, considering that both wrist deviation and wrist twisting are both curved movements - something has to straighten the pick
I definitely do in some passages, but not to an extent that causes discomfort. I could not access your video for some reason 
I think you might have misunderstood what the “linear pick movements” used in DWPS and UWPS mean. It is indeed pretty awkward to try and move the pick in a purely linear fashion as all joints can only rotate.
What is meant by “linear pick movements” is only that the pick trajectory appears linear when you look in the directions of the strings (i.e. the view one gets by putting a camera along the neck). There is still some rotation happening in the point of view of the player!
I suggest you don’t worry too much about the “linear” part of things. What really matters is that your picking motion generates escaped pickstrokes (either the upstroke or the downstroke) and that the movements doesn’t include stringhopping (wrist extension on each pickstroke).
Hope this helps!
p.s. I also can’t access your videos
Try changing your grip. A pad-side grip is much less prone to this. Might be that you’re already doing this, I can’t tell - your links aren’t loading for me.
You don’t have to want to use a different grip permanently. You’re just using that as a teaching tool. At some level you will need to zero in mentally on what it feels like to move only the joint you want to move, and that’s what diversity of approaches will give you. Once you learn what this relaxation feels like, you can apply it to the other ways you play.
@Troy, you were absolutely right - couple of days ago, I realised that I was letting the pick flop too much because my thumb was not really pressing on the whole pick, so my thumb joint needed to do extra work because of the lack of support in my pick grip. It’s hard to explain what I was doing exactly, but I hope that makes sense. Thank you too @Gazzo for the advice, that should stop some overthinking on my end
@Gazzo isn’t wrist extension what Albert Lee does? I find the “knocking” motion pretty awkward when I try it, but is that the motion you’re referring to?
I am not so familiar with Albert Lee, but at quick glance his rest position on the guitar seems to be an extended wrist. That’s perfectly fine! I was referring to something else.
I was referring to stringhopping which is a knocking motion when doing a downstroke and another knocking motion when doing an upstroke! In other words, there is wrist extension on every pickstroke. To me, it really feels and look like my hand is bouncing when I try to pick fast this way. Stringhopping renders the picking movement very inefficient and limits people in their picking speed. It’s not something you should “try” but something you should avoid!
The problem seems to be that this is a natural way people develop to change strings when picking. Especially when starting slow and gradually increasing the speed. Stringhopping works fine at “slow speeds” but then you hit a speed wall which you can’t break without changing your picking motion.