Ševčík’s 40 variations make us work through a wide range of off-string bowings.
Here in variation 20 he challenges our control of up-bow and down-bow ricochet at a relatively slow tempo, combined with passages of spiccato.
To slow ricochet down we often use a higher bounce or a longer stroke, however here we are limited in both the amount of bow and height of the bounce since we need to be ready for the spiccato passages in the middle of the bow. You can use a deliberate forearm action for the up bow or even try raising your right elbow slightly to help ‘lever’ the up bow onto the string.
Also think about whether the bow starts on or off the string. While the ricochet starts from the air, for instance in bars 1 and 2, the spiccato can start from the air as well or from on the string.
Remember your musical line and phrase off bars such as 8, 16 and 24.