  We discuss the impact of chiral symmetry constraints on the quark-mass
dependence of meson resonance pole positions, which are encoded in
non-perturbative parametrizations of meson scattering amplitudes.
Model-independent conditions on such parametrizations are derived, which are
shown to guarantee the correct functional form of the leading quark-mass
corrections to the resonance pole positions. Some model amplitudes for $\pi\pi$
scattering, widely used for the determination of $\rho$ and $\sigma$ resonance
properties from results of lattice simulations, are tested explicitly with
respect to these conditions.
