  A force applied to a spin-flipped particle in a one-dimensional spinor gas
may lead to Bloch oscillations of particle's position and velocity. The
existence of Bloch oscillations crucially depends on the viscous friction force
exerted by the rest of the gas on the spin excitation. We evaluate the friction
in terms of the quantum fluid parameters. In particular, we show that the
friction is absent for integrable cases, such as SU(2) symmetric gas of bosons
or fermions. For small deviations from the exact integrability the friction is
very weak, opening the possibility to observe Bloch oscillations.
