Left panels: mass versus the logarithm of the rotational period of a sample of 200 stars extracted from model M1 (black circles) at four different ages superimposed by the 75th percentiles of the log (P) (cyan diamonds). The best linear fits of the percentiles for 0.1 M_⊙ ≤ M_∗ ≤ 0.4 M_⊙ are shown as red lines. Right panel: slope of the best linear fits plotted as a function of age (red circles) superimposed with the values obtained by Henderson & Stassun (2012) for seven clusters of different ages (black circles).