Schradieck, The school of violin technics, Шрадик, упражнения для развития беглости на скрипке 

since this is meant to develop dexterity i would say to start as slow as needed to guarantee you're going to be positioning every finger correctly, and go up from there until you're satisfied with your accuracy, i would say that's the most didatic approach. But in case you need the numbers, start at about 50~60 bpm for the quarter note, repeat it A LOT until you no longer need to think about the order of the fingers, remember, this is not a reading exercise, it is a dexterity exercise, so decorating the pattern of each exercise is encouraged, then you start focusing on the way your fingers drop and leave the string, both movements should be very energetic to mantain precision. The level of the student should not matter for how you work the tempo up, you go up about 10 bpm everytime you feel the previous tempo feels way too easy (not comfortable! way too easy), and as i said, you go up until you feel satisfied, but to how fast you work this may depend on your level, for intermediate students, about 96 should be enough, for advanced students, at least 120. in this video the lady was playing at about 150~180, the first one was way faster than the others, but she stayed at about 160 throughout it. Hope this helps!

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