  We investigate the motion of test bodies with internal structure in General
Relativity. With the help of a multipolar approximation method for extended
test bodies we derive the equations of motion up to the quadrupolar order. The
motion of pole-dipole and quadrupole test bodies is studied in the context of
the Kerr geometry. For an explicit quadrupole model, which includes spin and
tidal interactions, the motion in the equatorial plane is characterized by an
effective potential and by the binding energy. We compare our findings to
recent results for the conservative part of the self-force of bodies in extreme
mass ratio situations. Possible implications for gravitational wave physics are
outlined.
