The alternation between orchestral refrains and virtuosic outbursts by the soloist (s) is known as

The alternation between orchestral refrains and virtuosic outbursts by the soloist (s) is known as fast movements in Baroque concerto as there is three movements in Baroque concerto, fast-slow-fast. Ritornello Form is used in the first and last movements of baroque concerto and this form every part is different but the passage sounds like it is similar to the other passage before that and the alteration is also included in this.