How can I recalibrate my Wiimote sword position while fighting?

Solution 1:

You can go to the pause menu and click the down button in the D-pad, and it will center the Wii remote. (If that's what you wanted.)

Solution 2:

You can recalibrate at any time by going to the pause menu and clicking the "Recalibrate Motion Plus" button in the bottom-left.