For those of you who teach (or could), what suggestions do you have for improving a player's ability to play fast licks with the bow? I'm thinking about passages like the opening of the Fourth Movement in the Tchaikovsky IVth; the Presto section in the Fourth Movement of the Dvorak VIth; the Russlan/Ludmilla overture; and most of the Mahler Vth. I'm sure each of us has a little list of favorites like these. There is another thread under "Technique" on improving speed in pizz playing, and some of the suggestions there probably carry over -- especially the need for relaxation in both hands. But does anyone have any concrete and practical suggestions -- drills, practice routines, etc. -- for raising one's personal "speed limit" when playing symphonic passages with the bow?