  Mass loss is a determinant factor which strongly affects the evolution and
the fate of massive stars. At low metallicity, stars are supposed to rotate
faster than at the solar one. This favors the existence of stars near the
critical velocity. In this rotation regime, the deformation of the stellar
surface becomes important, and wind anisotropy develops. Polar winds are
expected to be dominant for fast rotating hot stars.
  These polar winds allow the star to lose large quantities of mass and still
retain a high angular momentum, and they modifie the evolution of the surface
velocity and the final angular momentum kept in the star's core. We show here
how these winds affect the final stages of massive stars, according to our
knowledge about Gamma Ray Bursts. Computation of theoretical Gamma Ray Bursts
rate indicates that our models have too fast rotating cores, and that we need
to include an additional effect to spin them down. Magnetic fields in stars act
in this direction, and we show how they modify the evolution of massive star up
to the final stages.
