This is a romantic movement and the performance is 'too correct', the sound has to be more relaxed and natural in some points. The bow has to push more out of the string and relax more at the end of the bowing.
They talk about how to perform the beginning of the movement and they work on the speed and clarity of the string changes and on the contrast within a sequence.
Wies de Bouve gives an explanation about shifting and suggests keeping the contact point in a slow and expressive passage. It is necessary more bow in the arpeggios and vibrato to distinguish some notes and give more character. The slurs are organized in 4 and sometimes the piano imitates the double bass line (e.g. in the trill).
The student has to show the classical elegance contained in Hindemith's music. When finishing a phrase, we have to coddle it until the end.