I know this is a dated thread but too make a mention of something - i have carpal tunnel/tendonitis flare ups frequently - a few things helped me.
*PROPER SETUP on a bass - low action.
If you don’t know how to do this yourself, youtube Dave’s World of Fun Stuff - he is a friend of mine and pretty black and white - gives ALL his info on setups - sift thru the titles.
*The one finger per fret technique - biggest reason to CAUSE flareups - lots of true info online that support this - plus my own personal trials - from the 5th fret upwards sure - 1-5th fret, not a chance.
The finger/hand spread creates strain on tendons and muscles - doesn’t matter stretches or ‘you have to do it more often to get used too it’ - simply not true - those people just don’t have the inherit hand/arm issues - so they don’t realize that you simply can’t ‘work past it’. My respect gets lowered when someone THINKS it will simply ‘go away’. It does NOT.
*Technique - following up with my prior comment, just being conscience of a lighter death grip - some people find a chinkier neck also helps with carpal tunnel - less squeeze required - distance wise - on the hand itself.
Let’s face it - most of us do this for fun and won’t make it as a world class musician - so wouldn’t you rather be a good player (with decent technique) than not being able to play at all due to hand/arm injuries cuz you TRIED to follow the ‘PROPER technique’?
It should be a guideline - not a MUST.
(Look at numerous famous musicians - not PROPER techniques - Geddy Lee - mostly plucks with his index finder - tons of info from himself, stated his reasons - he did ok in life!
*pick versus alternating finger technique - I prefer fingers to a pick - but if my fingers slow down and become sloppy - i know carpal tunnel flareup is on the horizon…BUT if i start with my fingers and switch to a pick (when i feel the sluggish dexterity happening), then it seems to give me a break and allows me to keep playing - AND teaches me finger AND pick abilities. (win win)
These are my personal opinions on the subject - might be in the minority but meh…i do this for fun and mental escape from life.