After some other adventures I've reached a point in my life where I finally both have a little bit of free time and a little bit of spending money. I expect for this state to continue until the corrosion industry picks up again, so I decided that now was the point to give the Anglo concertina another go and develop a firm foundation.
For the past few days I have been following along with "Easy Anglo 1-2-3", playing somewhat regularly in the evenings and sometimes in the mornings. My play would consist of multiple sessions, about ten minutes in length, at which point I would do something else for a while. I can play the songs up to Frere Jacques now, following along with the tabs. (I know I should learn how to read and translate the notes on the staff, but I've already started one method and should probably see it through before starting another.)
Unfortunately, this morning I began to experience soreness in my left hand. It has persisted until now (~6pm central time) so I am putting the instrument down for a while. I'm not sure if I could actually give myself carpal tunnel syndrome playing concertina at this level for around 30 minutes throughout the day, but I don't want to accidentally ruining my hands.
I believe a part of this is not just using my weak hand in a new way, but also improper posture. When I played, I was playing with one side of the instrument's ends flat against my thigh. When looking up the video which accompanies the book I noticed that it was being played with the corner resting upon the thigh. I am wondering if this played a part.
Another thing that I am wondering is if there are suggested warm up exercises for the concertina, or if they would even be relevant at this stage.