Isis had to overcome some significant obstacles in order to achieve her goals. But she got what she wanted in the end.
She is also very linked with motherhood, magic, compassion and perseverance. She stands up for the weak and she uses her powers to help people who have none. Her appearance at your Root Chakra might indicate that you are expending your energy more on behalf of other people than you are doing for yourself.
Having her in this position might indicate that you are feeling proud, but possibly defensive. That you can feel powerful, at the same times as feeling exhausted with the need to be the fighter for freedoms and goods.
But remember that she won out in the end.