Proton and neutron polarized structure functions from low to high Q**2

Phenomenological parameterizations of proton and neutron polarized structure functions, g1p and g1n, are developed for x > 0.02 using deep inelastic data up to ~ 50 (GeV/c)**2 as well as available experimental results on photo- and electro-production of nucleon resonances. The generalized Drell-Hearn-Gerasimov sum rules are predicted from low to high values of Q**2 and compared with proton and neutron data. Furthermore, the main results of the power correction analysis carried out on the Q**2-behavior of the polarized proton Nachtmann moments, evaluated using our parameterization of g1p, are briefly summarized.