@KeksalotFirstly, calling powers like Super Strength and Super Speed unimaginative is a bit of failure of imagination itself. Surely it's the application of powers and the creation of an interesting, compelling character that necessitates and benefits from creativity the most. Hopefully it's also apparent that the aim is not simply to see who can come up with the most unique or broken powers.
Secondly, the limits of the different powers are, on some levels, being kept blurred. Part of the theme of the RP, Science vs magic or quantifiable vs mysterious, would be destroyed by a five paragraph treatment on each power, as that is neither magical nor mysterious. Again, the tone of the RP should make it clear this is not the sort of story where, to use your example, the super strong character immediately rips their own arms off. It's not mystical and not magical.
To answer your question more directly, yes, characters will be largely protected from their own powers. Pyrokinetics won't burn themselves alive, speedsters won't break their bones by coming to a sudden stop and so on. This should not, however, be seen a loophole to try and work a half dozen extra powers out of a single one. I would direct you to
@Undine's rule of KISS; Keep it simple, stupid.