User blog comment:Apocaylpse06/Ichigo Kurosaki's (New) Zanpakuto/@comment-1975828-20110815110510/@comment-4307134-20110817061751

But it wasn't HER power, it was his, when she made him a soul reaper, his power was greater then her original power. She awakened his soul reaper power. Byakuya cut off his power so he could not use it. Urahara made ichigo part Hallow in order to establish the connection between his power again.

Also, in this new manga, she seems as though she gave him the ability to regain his power, not take hers. but i think a side effect is that her spiritual energy becomes used up.