Evolution of the core rotation rate during the core-helium-burning phase as a function of the asymptotic period spacing for different initial masses. The models correspond to those presented in Fig. 4. The solid lines show the region where the central helium decreases from Y = 0.9 to Y = 0.1. The evolution proceeds from left to right during most of the core-helium-burning phase (solid lines). The data points correspond to the red-clump stars presented by Mosser et al. (2012). The magenta line shows a model where we assumed strong penetrative convection.