  We study the "improved dynamics" for the treatment of spherically symmetric
space-times in loop quantum gravity introduced by Chiou {\em et al.} in analogy
with the one that has been constructed by Ashtekar, Pawlowski and Singh for the
homogeneous space-times. In this dynamics the polymerization parameter is a
well motivated function of the dynamical variables, reflecting the fact that
the quantum of area depends on them. Contrary to the homogeneous case, its
implementation does not trigger undesirable physical properties. We identify
semiclassical physical states in the quantum theory and derive the
corresponding effective semiclassical metrics. We then discuss some of their
properties. Concretely, the space-time approaches sufficiently fast the
Schwarzschild geometry at low curvatures. Besides, regions where the
singularity is in the classical theory get replaced by a regular but discrete
effective geometry with finite and Planck order curvature, regardless of the
mass of the black hole. This circumvents trans-Planckian curvatures that
appeared for astrophysical black holes in the quantization scheme without the
improvement. It makes the resolution of the singularity more in line with the
one observed in models that use the isometry of the interior of a Schwarzschild
black hole with the Kantowski--Sachs loop quantum cosmologies. One can observe
the emergence of effective violations of the null energy condition in the
interior of the black hole as part of the mechanism of the elimination of the
singularity.
