Thumb

DEAR ALAN, i'm trying to play a trill with the thumb-is it true that the muscles which move the thumb up and down are slower than the muscles which move the thumb sideways? also-can you suggest me a way to use the thumb in trills but not to get "stuck"? thank you

You're getting stuck because there is some insidious "falling down" either in your thumb or your 2nd or both.... AFF