  Lattice QCD simulations provide a promising way to disentangle different
interpretations of hadronic resonances, which might be of particular relevance
to understand the nature of the so-called $XYZ$ particles. Recent studies have
shown that in addition to the well-established naive quark model picture, the
axial-vector meson $f_1(1285)$ can also be understood as a dynamically
generated state built upon the $KK^*$ interaction. In this work, we calculate
the energy levels of the $KK^*$ system in the $f_1(1285)$ channel in finite
volume using the chiral unitary approach. We propose to calculate the loop
function in the dimensional regularization scheme, which is equivalent to the
hybrid approach adopted in previous studies. We also study the inverse problem
of extracting the bound state information from synthetic lattice QCD data and
comment on the difference between our approach and the L{\" u}scher method.
