Great demonstrations! This is definitely rotator cuff. However it’s more shoulder-y than what Zakk does. You’re making a vertical tapping motion into the strings. Zakks motion follows a more blended elbow / shoulder path.
Evan Marshall on mandolin I think is also similar, as another reference point.
Oh man, that’s really reassuring. Thanks! And that Billy Strings clip is really interesting. It makes me wonder if pursuing a DBX motion in that style is something to experiment with.
Demo of how it actually looks when I use it normally:
https://youtube.com/shorts/dMLANz4_gv0
Very sloppy Double Thumbing technique (I’m not great at it on guitar), so you can see the similarity:
In this I say my “elbow is locked” but I meant my forearm.
As for how it evolved, I think it just came very naturally from the double-thumbing motion.
(edited the below a little for clarity)
The slapping(edit - doublethumbing) motion on bass HAS to be USX, if you want to also produce the “pops”, because those are always produced with the “upstroke” part of whatever(edit - most) slap motions. (I guess you COULD do DSX double thumbing, but I don’t know how the pops would work)
For example, if you use the very common Forearm Rotation slapping motion, the pops are in the second half of the rotation. You slap down with your thumb on the first half of the rotation, then put your finger under the string, then do the second half of the rotation, and the pop happens automatically as you rotate “up.” (edit - The finger is also involved in “letting go” of the string at the correct time)
Same with this motion - the pops are part of the “upstroke” of the motion. It’s like (Downstroke/Slap) - (Thumb Flick/Slap) - (Upstroke/Pop). That’s the triplets. But when I just do straight thumb, no triplets, the thumb is locked.
(edit - This is why the motion is done the way it’s done by so many bassists. It has to be an elbow motion to get the clean up/down with the thumb, and it has to be USX to facilitate the pops).
So, when I picked up a guitar, my first two good motions were this, and forearm rotation (also because of slapping). This was back in 2006 or so. I didn’t even realize DSX was a thing at all until a year or two ago (thanks @troy). I just assumed everybody was playing USX all the time.
It’s fast - about as fast as my DSX elbow, so like 250bpm on a single note, I think? However, I also don’t know if it’s capable of doing a secondary motion - it feels like I have to have a very locked forearm to do it, unlike Elbow DSX. So, I don’t use it very much these days, I’m more RDT DSX/DBX and Elbow DSX.
WHAT THE ACTUAL EFF?!?!?!! 
I was under the clear impression that “elbow” motion is only capable of DSX - end of story. So now we have discovered that it can also do USX? Probably DBX also? How did I miss this? Please clarify my man…
The big difference here is the addition of the shoulder. This stuff is not the simple hinge elbow motion most often thought of when people talk about picking from the elbow 
So don’t worry, you have not been led astray intentionally or accidentally. And just having an elbow motion doesn’t mean this elbow shoulder blend is just a step away. Ask me how I know…
hahaha No worries, I was just wondering if I missed something - I of course immediately messed around with my 'ole faithful elbow stuff and - yep, same old same old! lol The “trick” is using the shoulder to get that USX, which is easier said than done. lol back to regularly scheduled programming! hahaha
Have you had a look at any Tosin Abasi footage of him doing his thumping and seeing if he also uses this motion?
I learned this motion recently, I had been thinking about writing up a post on it.
In August 2020 I dislocated and tore my right shoulder in training accident in BJJ. I had been experimenting with learning DSX elbow movement at the time, but the tracking was very hard on my shoulder, so I focused my attention on other things.
I did physiotherapy and rehabilitation work. There’s no pain, but there had been a lingering feeling of proprioceptive and kinaesthetic “wrongness” for several years. My shoulders have always been hypermobile, but there were some positions and movements where my shoulder felt very unstable, and some situations in Jiu-Jitsu where I simply could not return my shoulder to a safe position. Whatever muscles I needed to activate, I simply couldn’t activate them, despite having passed the strength standards in rehabilitation exercises I was prescribed. It never stopped improving, but improvement had slowed significantly.
A couple of months ago, I was experimenting with picking fully floating on an acoustic guitar and I tried the elbow and rotator cuff movement. I felt my shoulder muscles activate dramatically. After about a minute, my muscles were twitching and my shoulder and thoracic spine was popping as I moved.
The next day, my shoulder felt better than it had in years. Less “wrongness” and stronger and more stable in the weak positions. I decided I would try to train the movement with the picking rudiments I teach my students.
In the last couple of months, my shoulder has improved hugely. This movement is literally rehabilitating my shoulder.
I’ve been careful not to put too much stress on my body, progress with the movement has been measured but deliberate. I haven’t started using it to play lines, but it’s working very well on basic patterns. It’s stupid fast and blends seamlessly with my dart-thrower USX form. I suspect it may be the “warp” movement that Shawn Lane used for his absolute fastest playing.
Also, I wouldn’t be surprised if the basic movement appears in other applications. I spent a few years playing acoustic fingerstyle almost exclusively. I remember trying to learn clawhammer, but I couldn’t get the hang of it. I tried it again recently, and I could do it almost immediately. It turns out that the clawhammer is essentially the dart-thrower action.
And of course, Molly is a dart-thrower based picker, too.
Have you had a look at any Tosin Abasi footage of him doing his thumping and seeing if he also uses this motion?
This is a great question that I hadn’t even considered -
I can’t really tell. If he does, it’s subtle. He primarily uses his thumb and forearm rotation (look at his knuckles) to produce the double-thumb motion. He is moving from the shoulder, but in that video, it kind of looks like it’s just to track string changes (to my wholly untrained eye).
Doesn’t look like it, to me.
I tried to find footage of Tosin alternate picking, to see if he’s using an Elbow USX motion, but he’s just using his wrist (boring).
Interesting side note - a lot of bassists include the “flappy-arm” rotator-cuff motion to their regular slap bass playing. You can see that in this video of Mohini Dey (who’s absolutely tearing it up, by the way):
You can see it throughout, but it’s really clear around 3:20 when she does that fast triplet(?) thing. Not double thumbing, but still incorporating rotator cuff and elbow motion to sort of “flap” her whole forearm.
Have you ever tried doing any kind of double-thumbing with the same motion? It’d be super interesting to see if a person can translate the motion from pick to thumb, instead of the other way around (like I did).
I can try to make a little tutorial on the motion. I used to teach the double-thumbing motion to bass students a long time ago, so I imagine the basic idea’s the same.
I’d love to see it! It’s be great to see it in action and explained!
Please do Tom! I am a big fan of your insights and would really enjoy seeing your take on this!
This is not really elbow technique – it’s shoulder rotation with some elbow. It’s not a thing where a player who is an elbow player, like Vinnie Moore, will incorporate this and have access to both string changes. At least, I haven’t seen it. It’s a USX technique that does only USX vocabulary.
I do this motion, and it’s a USX-only technique for me. I can’t make it do DSX and I’m actually not good at “regular” DSX elbow motion. So I don’t really even think of this as being part of the elbow universe, in the way that we traditionally understand elbow as one of the common DSX mechanics.
Also, we profile this in the Primer here:
@Troy Thanks for the reply - this is super interesting because my initial motion seems like it was THAT - definitely an elbow thing… but I can do the repeated strings 2x like the primer starting on a downstroke with a bit of supination no sweat. That’s what I used to do! Some slight swiping going on as I messed with it after watching the primer, but definite USX consistently. Same thing with a 2nps pentatonic sextuplets thing. I never practice with this form anymore and I can just “do it” which is cool. Another tool in the toolbox… I always wondered why I had to pronate my wrist to do DSX with elbow otherwise it felt awfully uncomfortable. I guess now I know!
-------------------------------------1-3-5-1-3-5 etc–
-----------------1-3-5-1-3-5---------------------------
1-3-5-1-3-5--------------------------------------------
and
—15-12---------------------------------------------------------------
-------------15-12--------------14–12------------------------------
-----------------------14-12---------------14–12-------------------
---------------------------------------------------------14–12-------
Troy mentioned Evan Marshall earlier so I want to share this insanity.
No, I’ve never tried it. I don’t play bass, and I’ve never cared much for slapping or thumping on a guitar.
I have about a dozen ideas for posts that I’ve been meaning to write up. I have some drafts in progress, finding the time to finish them has been difficult. Some that are more developed are a post on Eric Johnson’s fretting mechanics, an updated post on the EDC principle (now that I have a much deeper understanding of the topic and a lot of my own EDC based vocabulary), reflections on what I’ve learned/discovered since I started teaching, and some insights I’ve had on synchronisation.
Just to keep everyone salivating, since it was my request, Tom sent me his first draft of this ages ago. It’s very dense and very cool. I was immediately given ideas for how someone who’s a DSX player could capitalize on the concepts.
I just realised that the first draft was sent to you about the time I got engaged. That’s more than 18 months ago now.
I opened up the current draft and it’s more than 10 pages in Word in a small font (about 6000 words and without diagrams) and I haven’t even explained the fives mechanics yet. I also mean to give examples of all the clever ways that Eric can uses finger rolls to link with hammers/pull-offs, slides and position shifts, how the roll is often masked by fretting a note between the rolled notes, and how his fretting hand damping can mute a fretted note on an adjacent string to be “revealed” later.
I’m going to make a sincere effort to get this one done this week. I’ll never finish anything if I keep switching between different projects.
I was also doing this. When trying to push my forearm/wrist technique to go faster, I unknowingly switched to an elbow motion, while still escaping on the upstrokes. So I assume it’s a similar motion to what is being described anyway. I’ll mess around with it and see if it’s something worth pursuing!
Hi everybody. I was asked to make a short discussion/tutorial video on this movement by @Toad.
The first video is for discussion/context only, the tutorial begins in the second video:
I’m curious about your dart-thrower motion - you’re doing it with a supinated forearm position, yes? My experimentations with dart thrower motion have involved pronating the arm, but if I can do it from a supinated position that would be far more convenient.
I made this video on the dart-thrower for the forum in 2023:
