Primary Motion And Speed
The tendency toward primary motion is broadly consistent across musical vocabulary, but players do appear to change it — and often even their musical vocabulary — at different tempos.
Double Escape to Single Escape Switching
One such change which we have observed nearly universally in our interviews is the switch from single escape to double escape motions as tempos increase. This change is most notable when the phrase in question can be played with simpler motions without negatively impacting the end result, such as single-string or tremolo playing.
For example, bluegrass great David Grier’s DBX wrist motion is the one he relies on at medium speeds:
But at elevated tempos, he switches to a mix of motions, both double and single escape, in which DSX actually appears to be the new primary:
Interestingly, this is still wrist motion, and still performed using the same pronated forearm setup that David uses for medium-speed playing. He’s just changed the type of wrist motion he’s making, from double escape to downstroke escape.
Multi-instrumentalist Andy Wood also changes his primary in a similar fashion, choosing a wrist-driven DBX motion at medium speeds:
Like David, Andy switches to a DSX primary for faster playing. This motion is still provided by the wrist — it’s just a different wrist motion:
Andy is also a world-class mandolinist, and it’s interesting to note that he maintains this same primary shift on that instrument as well. In this fascinating excerpt from his acoustic interview, he discusses what it feels like to switch between these two motions:
Speed-Dependent Musical Vocabulary
When David and Andy switch primary motions, they also make subtle changes to their arrangements to accommodate the specific needs of DSX motion: inserting legato notes, or rearranging phrases on the fretboard, so that downstrokes are more often the final note on the string. They sometimes introduce form shifts or helper motions to make certain phrases playable that might not work with DSX alone. This is actually complicated work, and when done consciously or deliberately, requires a fair amount of knowledge about picking technique of the sort you’re presumably learning right now!
But in trying to imagine how the motor system could do this on its own, primarily by the feel of physical feedback, we can think again in terms of probability. Just as with a beginning metal player, it may be that when you tell a bluegrass player to go fast, single-escape joint motions are the first ones they discover that can do that. And once they have those, it’s easy to imagine that a really good player like David Grier would experiment with different fretboard phrases until he found a few of them that happened to feel really smooth at that speed. And just like that, a slightly different high-speed vocabulary is born.
In other words, we’re not saying that DBX motions are slower than USX and DSX motions. We don’t know that for sure, and the answer probably depends a lot on which joints you’re using anyway. But what we do know is that single escape motions are often simpler, relying on a single joint moving in a single axis of its operation. Again, the elbow is a great example of that. So when speed is introduced as the main requirement, it may just be that “go fast” leads you to those motions first. And since time is money, even for your motor system, the first good solution you discover may very well be the one you decide to stick with.