Technique for double-stopping a whole song?
 

I'm pretty new to double stops. I've used them before, sparingly, but I'm in a jazz duo where the guitarist/composer is writing a lot of new songs using constant double stops. Attached is an example of page from a score showing the last part of a new song where everything is double stopped. Actually, the four-page score is entirely double stopped. Whew! (This particular song is in the style of Jean-Luc Ponty.)

My particular issue is playing this steady frequency of double stops is stressing my left forearm (the fingering arm). Usually I play standing up, and I find it's a bit easier playing this music while sitting down. But it's still causing too much stress in the forearm and I'm not sure if I can keep it up. Is this just a matter of building endurance, or are there some tips anyone can offer on how to approach this music technique-wise?

Thank you.

P.S. fwiw, the tempo of this song is 120 so the double-stopped changes move along at a pretty good clip.

Sounds like you might need to lower your action. Or come up with a less difficult (physically) bass line that still sounds good to his ears.

EDIT: If it hurts/ is uncomfortable, do NOT try to tough it out/ build endurance... that will lead to a repetitive stress injury AT BEST.

well it is mostly 5th and 6th ... there isn't a big problem here, just need some practice. I would use my index and pinky for most of that thing on two strings ... seem very simple to me, after that it is just a matter of practicing it enough to put it up to 120 bpm.

Maybe you'll feel more confortable doing that in two hands tapping.

Also if you have hand pain for that kind of stuff ... your playing position may be the reason ... like if you put your thumb over the neck, it might be a problem with that also your action may be too high.

I've been practicing 5th and 6th double stops up and down the neck and it's getting a bit easier, but what a workout! I am aware of the potential for injury so taking it slow.

My action is already quite low. And there's no "negotiation" on the bassline - it needs to be played as written!