The complexity of a compactly supported diffeomorphism of a smooth manifold can be measured by the (polynomial) volume growth of submanifolds under the iterates of the map. In this talk, we are interested in a fibered twist, a special symplectomorphism of a Liouville domain with a periodic Reeb flow. Using Floer theory, we obtain a lower bound of the slow volume growth in the components of fibered twists. Other entropy-type invariants are also discussed.