Got attacked today when I was on the ground and had something like 2 stamina, and combat mobility stood me up and popped my muscles in the process. It seems like it'd be more logical if it just didn't activate when you don't have enough stamina to complete the maneuver. Ideally, there ought to be some sort of setting to toggle that would either stand you up if you have any stamina at all, or would only activate the maneuver if you had enough to use it without popping your muscles.
You hear a loud POP come from your muscles!
Sensing an impending attack, you manage to roll hard to the side, and then leap to your feet!
A lesser minotaur swings a curved silvery white greataxe at you!
AS: +384 vs DS: +422 with AvD: +46 + d100 roll: +77 = +85
A clean miss
I guess it would have hit me without mobility, but probably not very hard.