Comparison of AB Dor A with a set of PMS evolutionary tracks with [Fe/H] = 0 for different initial helium abundances (standard abundance, left panels; low abundance, right panels), and for different mixing length values α_ML (1.74, top panels; 1.00, bottom panels). The shaded area corresponds to the region between track with masses in 0.82−0.98 M_⊙, as given by the uncertainty on dynamical mass.