A bass run is an instrumental break in which the main vocal or melody line rests (pauses, takes a "break") and the bass instruments and line are given the forefront. The technique seems to have originated in the marches of the "Sousa school", though its resemblance to call and response techniques familiar to African American musicians indicates an earlier origin. (van der Merwe 1989, p.283)

Source

• van der Merwe, Peter (1989). Origins of the Popular Style: The Antecedents of Twentieth-Century Popular Music. Oxford: Clarendon Press. ISBN 0193161214.