We present a new normalization condition for the axial current, derived from
the PCAC relation with non-vanishing quark mass. This condition is expected to
reduce mass effects in the chiral extrapolation of the results for the
normalization factor Z_A. The application to the two-flavor theory with
improved Wilson fermions shows that this expectation is indeed fulfilled. Using
the Schroedinger functional setup we calculate Z_A(g_0^2) as well as the vector
current normalization factor Z_V(g_0^2) for beta = 6/g_0^2 >= 5.2.Comment: 15 pages, 4 figures, 2 tables, JHEP styl