Board Thread:General Discussion/@comment-1.40.59.59-20160717064827/@comment-26018514-20160717082328

SpiritedDreaming wrote: The first option, that once you run out of aura you can't use your semblance until it recharges, is the more widely accepted theory that I have seen.

They aren't mutually exclusive, both are also likely to co-exist, it just depends on exactly what the semblance does and how much aura it uses.