Ševčík gives specific directions to lift the bow after the second slurred note.
Every technical task in an absolute sense takes time. For instance a shift between 2 quarter notes, however quickly it is done, will take a certain amount of time. In technical tasks we take this time from the old note (the first note) so that the new note (the second note) is rhythmically accurate.
The same principle applies here; the lift between the slur and the placing back on the string will take a certain amount of time. Here the 2nd note of the slur is cut slightly short to allow this time to lift and replace the bow. Be sure however to maintain the legato between the two notes of the slur and do not release the bow frictionThe degree of contact between bowhair and string. too early, the second note should still be as clear and resonant as the first.
When practising this excerpt slowly, think ahead to when the bow will cross strings and make sure that the cross happens in time. The bow should be at the correct string level in order to begin the note with confidence and clarity!
Half- tempo practice followed by performing the excerpt at tempo is an effective way to program fluid actions in both the right and left hands.
SEE
Introduction to Practice for the section on Tempo