Uilleann17 wrote:
is the technique easier on the thumb joint with the NSP than with the UPs? I have developed a tricky bit of arthritis affecting my UP playing but I do not want to give up on piping altogether.
I would say almost certainly not. NSP are not very forgiving of arthritic thumbs - and bad posture or hand position will almost certainly exacerbate the condition.
For the left thumb there is a difference in how the thumb is held to cover the rear hole; typically more bent meaning the knuckle joint is more active. The left thumb also provides a lot of chanter support (when the right thumb is off the chanter playing the keys). The right thumb requires significantly more articulation to play all the keys, you need a high degree of movement in all three joints in the thumb.
A secondary issue is chanter balance: On a standard 7k chanter, the centre of gravity is between the two hands and the thumbs are close to the pivot. On an extended chanter (13k+) the centre of gravity moves down to the right hand or even below that, the pivot point has moved further away. This means that whenever either thumb is used, two things happen; both thumbs rotate the chanter in the same direction and the movement effect is amplified. You need much finer control of the hands to master an extended chanter.
Rob