  We study the quark angular momentum distribution in the nucleon within a
light-front covariant quark model. Special emphasis is put into the orbital
angular momentum: a quantity which is very sensitive to the relativistic
treatment of the spin in a light-front dynamical approach. Discrepancies with
the predictions of the low-energy traditional quark models where relativistic
spin effects are neglected, are visible also after perturbative evolution to
higher momentum scales. Orbital angular momentum distributions and their
contribution to the spin sum rule are calculated for different phenomenological
mass operators and compared with the results of the MIT bag model.
