In Ottoman classical music, usul is an underlying rhythmic cycle that complements the melodic rhythm and sometimes helps shape the overall structure of a composition.
But a student learning Turkish music in the traditional meşk system first memorizes the usul kinetically by striking the knees with the hands.
This pedagogical system helps the student memorize the composition while internalizing the underlying rhythmic structure.
Usul patterns have standard pronounceable vocables built from combinations of the syllables düm, dü-üm, tek, tekkyaa, teke, te-ek, where düm, dü-üm indicate a strong low beat of single or double duration, and tek, tekkya, teke, te-ek indicate various combinations of light beats of half, single or double duration.
When performing music for the Mevlevi ceremony, drummers traditionally play embellished (velveleli) versions of the usuls.