msmay, thank you for the exercises, if it is just a matter of training to fix it, that's great. I do want to ask for a bit of clarification though...
In exercise #1, are you talking about pressing all fingers flat down (fully in contact with the table), having them in a piano playing curved position with only the tips touching, or mostly touching with the middle joints somewhat elevated? I used to have a similar exercise with fingers curved around the neck of a guitar pressing against the fretboard. This discussion may need to move to the music thread.
I do notice that if you are talking about fingers being held very flat, my ring fingers tends to bend backwards at the middle joint. If you are talking about fully curved fingers, most of them bend back nicely at the base joint for a hammer action, but the ring fingers tend to go somewhat sideways instead. I may have a go at trying to aid the motion of that finger with the other hand for a while (don't worry, if I injure it, it is my own dumbness that caused it, I used to horrify my guitar teacher with practicing "every breath you take" with spools between my fingers to get the necessary reach...no telling what damage THAT did).
I am not quite sure what you mean by dragging the little finger in exercise #2.
It sounds like it may help to go work on my parent's manual typewriter again, I wonder if one of those could be easily wired to be a computer keyboard

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I also wonder if it throws off beginner music students to have a hypermobile teacher

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Congratulations on the dining table, i usually leave it to my husband to build the big items (when there is time, energy and inclination), mainly because I hate to start projects that will take up lots of space whether or not I finish them. I somewhat dislike using hammer/nails and glue when building if i can avoid it because I know that I'll want to dismantle and reconfigure later. It's surprising that I've managed to build anything.
...antimatter
p.s. that's exactly the sort of exercise I like, very little motion, not much to remember and no chance of getting dizzy

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