The influence of neutron-proton correlations on backbending is investi
gated in a single-j-shell model. It is shown that these correlations a
re quenched if the neutrons and Protons fill a high-j intruder orbital
asymmetrically. This is due to the repulsive neutron-Proton correlati
on energy in these configurations and is responsible for the observed
forking of the ground state band into proton and neutron S bands.