Interesting indeed!
Milking, gliding, etc.
In my case I feel it like I’m “pushing” for the down downs.
@s_linste def great advice here, I couldn’t catch the fretting issue, folks here are fantastic!
My emphasis was on the fist note being pushed, then up, then the down down (DD) which is another push motion. I’m using the word push as opposed to the up which is almost always a wrist motion while the down can often be an arm motion for first note and string change (DD) actions.
In my journey I could never get the two sets of muscle thing, one for up strokes and another for down strokes, I’m beginning to understand why I went through all those months of excruciating pain, I was using wrist action for both up and down, all the time.
Over the last few weeks I’ve been taking a closer look at my picking hand thumb grip, I used to curl my index and my thumb was bent inwards as well. On looking at better players, “most” had their thumbs extended and straight for the “most” part, including YJM, though I’d notice a quick flick here and there, even blitzkrieg has it!
I’m pretty convinced now the thumb bend is induced only on the upstroke, perhaps it lends move velocity in combination with arm, wrist and a bit of thumb action to help tracking and emphasise a beat ( triplet, etc) feel.
At this point I’m probably over thinking it as i really have no control over it while playing, just that I wanted the thumb fully extended on down strokes, for power, hand position stability ( allowed for seamless and rapid tracking jumps without much drama) while maintaining consistent string muting too!
edit:
I guess I must add that trying to keep the thumb straight on down strokes has also helped bring more arm motion. This brings wrist, arm and thumb action into a blend that’s hard to describe still. But it has certainly helped reduce the effort required, and on the other hand increased power.
As to why I’m emphasizing power is in this clip. I need to slam (downward push) the string and equally provide muting pressure as my action is quite high to get the right tone and feel. Just a phone cam here:
The straight thumb and uncurled index finger grip has added a lot of good things to the mix in my case. Just wanted to stress that this might help others if they’re not aware of it