  We review how the Regge trajectory of an elastic resonance can be obtained
just from its pole position and coupling, using a dispersive formalism. This
allows us to deal correctly with the finite widths of resonances in Regge
trajectories. In this way we can calculate the Regge trajectories for the
$K^*(892)$, $K_1(1400)$ and $K^*_0(1430)$, obtaining ordinary linear Regge
trajectories, expected for $q \bar q$ resonances. In contrast, for the
$K^*_0(800)$ meson, the resulting Regge trajectory is non-linear and with much
smaller slope, strongly supporting its non-ordinary nature.
