Context : Precise determination of stellar masses is necessary to test the validity of pre-main-sequence ( PMS ) stellar evolutionary models , whose predictions are in disagreement with measurements for masses below 1.2 M _ { \odot } . To improve such a test , and based on our previous studies , we selected the AB Doradus moving group ( AB Dor-MG ) as the best-suited association on which to apply radio-based high-precision astrometric techniques to study binary systems . Aims : We seek to determine precise estimates of the masses of a set of stars belonging to the AB Dor-MG using radio and infrared observations . Methods : We observed in phase-reference mode with the Very Large Array ( VLA ) at 5 GHz and with the European VLBI Network ( EVN ) at 8.4 GHz the stars HD 160934 , EK Dra , PW And , and LO Peg . We also observed some of these stars with the near-infrared CCD AstraLux camera at the Calar Alto observatory to complement the radio observations . Results : We determine model-independent dynamical masses of both components of the star HD 160934 , A and c , which are 0.70 \pm 0.07 M _ { \odot } and 0.45 \pm 0.04 M _ { \odot } , respectively . We revised the orbital parameters of EK Dra and we determine a sum of the masses of the system of 1.38 \pm 0.08 M _ { \odot } . We also explored the binarity of the stars LO Peg and PW And . Conclusions : We found observational evidence that PMS evolutionary models underpredict the mass of PMS stars by 10 % - 40 % , as previously reported by other authors . We also inferred that the origin of the radio emission must be similar in all observed stars , that is , extreme magnetic activity of the stellar corona that triggers gyrosynchrotron emission from non-thermal , accelerated electrons .