Combat Stamina

You gain a stamina pool. After you make an
attack roll with a manufactured weapon,
unarmed strike, or natural weapon attack with
which you are proficient, but before the results
are revealed, you can spend up to 5 stamina
points. You gain a competence bonus on the
attack roll equal to the number of stamina
points spent. If you miss with the attack, the
stamina points you spent are lost. You can
spend your stamina points to use any combat
tricks associated with combat feats you possess.