bear down

exert a force with a heavy weight; "The snow bore down on the roof"

contract the abdominal muscles during childbirth to ease delivery

to make a rush at or sudden attack upon, as in battle; "he saw Jess charging at him with a pitchfork"

exert full strength; "The pitcher bore down"

pay special attention to; "The lectures bore down on the political background"

exert a force or cause a strain upon; "This tax bears down on the lower middle class"