Chromosome movement is essential to genome segregation upon cell division. Active force generation at the kinetochore by both microtubule-based motor proteins and microtubule dynamics is thought to power chromosome movement. How do spindle forces oppose kinetochore-based forces to specify that chromosomes, instead of microtubules, move? To answer this question, one must uncover the contribution of spindle mechanical architecture to chromosome movement. In Aim #1, we will determine how the spindle exerts force on kinetochore-microtubules to oppose kinetochore-based forces and thereby impose chromosome movement. In Aim #2, we will determine how these spindle forces on kinetochore-microtubules are dynamically maintained during continuous spindle reorganization and molecule turnover, as well as external insults. Together, our results will provide insight into how the load of chromosome movement is born by such a dynamic machine as the spindle.