  We study a target sample of 68 low-mass objects (with spectral types in the
range M4.5-L1) previously selected via photometric and astrometric criteria, as
possible members of five young moving groups: the Local Association (Pleiades
moving group, age=20 - 150 Myr), the Ursa Mayor group (Sirius supercluster,
age=300 Myr), the Hyades supercluster (age=600 Myr), IC 2391 supercluster
(age=35 - 55 Myr) and the Castor moving group (age=200 Myr). In this paper we
assess their membership by using different kinematic and spectroscopic
criteria. We use high resolution echelle spectroscopic observations of the
sample to measure accurate radial velocities (RVs). Distances are calculated
and compared to those of the moving group from the literature, we also
calculate the kinematic Galactic components (U,V,W) of the candidate members
and apply kinematic criterion of membership to each group. In addition we
measure rotational velocities (v sin i) to place further constraints on
membership of kinematic members. We find that 49 targets have young disk
kinematics and that 36 of them possibly belong to one of our five moving
groups. From the young disk target ob jects, 31 have rotational velocities in
agreement with them belonging to the young disk population. We also find that
one of our moving group candidates, 2MASS0123- 3610, is a low-mass double lined
spectroscopic binary, with probable spectral types around M7.
