  The evolution of a scalar field is explored taking into account the presence
of a background fluid in a positively curved Universe in the framework of loop
quantum cosmology. Though the mechanism that provides the initial conditions
for inflation extensively studied in the literature, is still available in this
setup, it demands that the initial kinetic energy of the field be comparable to
the energy density of the background fluid if the field is initially situated
at the minimum of the potential. It is found, however, that for potentials with
a minimum such as the chaotic inflation model, there is an additional mechanism
that can provide the correct initial conditions for successful inflation even
if initially the kinetic energy of the field is subdominant by many orders of
magnitude. In this latter mechanism the field switches direction when the
Universe is still in the expanding phase. The kinetic energy gained while the
field rolls down the potential is subsequently enhanced when the universe
enters the collapsing phase pushing the field one step up the potential. This
behavior is repeated on every cycle of contraction and expansion of the
Universe until the field becomes dominant and inflation follows.
