  One of the characteristic features of low-mass stars is their propensity to
shed large amounts of angular momentum throughout their evolution. This
distinguishs them from brown dwarfs which remain fast rotators over timescales
of gigayears. Brown dwarfs with rotation periods longer than a couple of days
have only been found in star forming regions and young clusters. This is a
useful constraint on the mass dependency of mechanisms for angular momentum
regular in stars. Rotational braking by disks and winds become highly
inefficient in the substellar regime. In this short review I discuss the
observational evidence for the fast rotation in brown dwarfs, the implications,
and the link to the spin-mass relation in planets.
