has been answered more than once.
A: You either use your action or you do not, there is no try. If you use your move action to get up, even if you are knocked back down, you have still used your move action.
A.1: If an action must be successfully completed to be considered an action
A.1.a: The world has no actions which are attempted, but not successfully completed, or
A.1.b: The world has actions which are attempted, but not successfully completed, but which are not considered actions.
The problems with this viewpoint are so obvious and pervasive that I have no interest in running or playing in a game where either A.1.a or A.1.b are true.
YMMV.
One might then say that an action is used either (1) when the action is initiated or (2) when the action is resolved.
1. Getting up is an action.
2. Getting up is initiated with the decision to get up.
3. Getting up is resolved when you either succeed in getting up or you do not.
Either way, in LostSoul's colour, a decision is made (fighter attempts to get up) and a resolution is determined (he fails).
RC