  We study the modification of the nucleon axial form factor in nuclear matter.
The internal quark substructure of the nucleon is self-consistently described
by the quark meson coupling model. We find that the axial form factor of the
bound nucleon is quenched considerably from that of the free nucleon. The axial
vector coupling constant is reduced by roughly 10% at normal nuclear matter
density and the axial form factor varies within 8% for moderate momentum
transfer.
