  The couplings of the electroweak effective theory contain information on the
heavy-mass scales which are no-longer present in the low-energy Lagrangian. We
build a general effective Lagrangian, implementing the electroweak chiral
symmetry breaking $SU(2)_L\otimes SU(2)_R\to SU(2)_{L+R}$, which couples the
known particle fields to heavier states with bosonic quantum numbers
$J^P=0^\pm$ and $1^\pm$. We consider colour-singlet heavy fields that are in
singlet or triplet representations of the electroweak group. Integrating out
these heavy scales, we analyze the pattern of low-energy couplings among the
light fields which are generated by the massive states. We adopt a generic
non-linear realization of the electroweak symmetry breaking with a singlet
Higgs, without making any assumption about its possible doublet structure.
Special attention is given to the different possible descriptions of massive
spin-1 fields and the differences arising from naive implementations of these
formalisms, showing their full equivalence once a proper short-distance
behaviour is required.
