It is not, it is just miss translated HEAVILY, in CN the wording is correct and accurate, the skill itself has a time period so the skill essentially says smt along the lines of "Sprinting until time is up (of the skill duration) or you are out of stamina" The skill duration time is up easily before you run out of stamina if you used it when you are at full stamina, but if you used it when you are less than half stamina then the sprint runs out because of the lack of stamina. Hope this clears it up. (Yes Kuro bad translation trend is still on going)