Wrist braces generally consist of some
flexible material
with
metal splints embeded in them. When you strap them
on, the prevent you from bending your
wrist up or down
to a great degree.
The theory is that making repetitive movements with
your fingers while your wrist is flexed wears down the
tendons, leading to pain and inflamation in them (tendonitis), and
eventually to constriction of the nerves running through the wrist (carpal tunnel) by the inflamation.
This is extremely unpleasant, and I am very grateful for
my wrist braces.