The last beat of any measure, usually a weak beat. It is called the " upbeat " because the conductor always directs it with an upward swing of the baton or hand. This anticipates the first beat of the next measure, the " downbeat ", always directed by a downward swing of the baton or hand.the upward movement of the conductor's baton or hand. the upbeat precedes a strong beat and it is also known as the 'weak' beat. If the rhythm is syncopated, the main accent falls on the upbeat