I use my hands a lot. A whole heck of a lot, and also I do a lot of knitting, every day. I don’t knit particularly fast, but I do knit a lot. It’s only expected sooner or later something in the mechanism of movement would start hurting.
I figure I can tame my thumb and teach my hands to move in different ways. My left thumb, that most useful thing, moves in continual little pressing motions, and while I move a stitch to ‘feed’ into the right hand’s fingers looping the yarn, and when I transfer the knitting to be held by the left hand while I reach for more yarn, the left thumb has a light clamping action. It all adds up.
So just for a short time so I can figure out what I’m doing, I’m wearing an elastic ‘bandage’ which keeps my left thumb from moving about much, so I must figure out other ways of doing things. For one, learning how to not feed the stitches so much , trusting that the stitches will make it over to the right hand without my bending and scooting so much with my thumb , and I’m learning to take up my knitting with my right hand while my left reaches for more yarn.
Either warning or fact : knitting excessively , whether for a past-time or production, eventually will cause ligament & muscle problems. Have you suffered injury from knitting in the past or are you presently beginning to ? Then my advise to you is to learn more ergonomic methods right away, and to not think it will just go away without diligent retraining of your movements.
Bandaged but not shackled… I knit on , with a little help from Tiger Balm. Oh, and glucosamine & chondroiton supplements daily.