bear down

verb

1. exert a force with a heavy weight"The snow bore down on the roof"
2. contract the abdominal muscles during childbirth to ease delivery
3. to make a rush at or sudden attack upon, as in battle"he saw Jess charging at him with a pitchfork"
4. exert full strength"The pitcher bore down"
5. pay special attention to"The lectures bore down on the political background"
6. exert a force or cause a strain upon"This tax bears down on the lower middle class"