Evolution of rotation on the MS as a function of the central mass fraction of hydrogen for all the stellar models from 1.7 to 120   M_⊙. Left: evolution of the equatorial velocity. The curve for the 1.7   M_⊙ is the bottom black line at the beginning of the evolution, and that for the 120   M_⊙ the upper red line (increasing initial equatorial velocity for increasing mass). Right: evolution of the V_eq/V_crit ratio for models with M_ini = 1.7, 15, and 60   M_⊙ at two different metallicities.