I could be wrong, (Fruipit, feel free to correct me if that's the case), but I'm pretty sure "maintaining" is the present participle form of maintain, and not a gerund. Present participles and gerunds are a pain because they both follow the form of verb + -ing ending.
Now, because "maintaining" is used to modify Elsa, it functions as a verb. Contrast this with a sentence like "Running is my favorite activity." "Running" is a gerund in this case because it stands as the subject of the sentence and is even modified by a verb, "is".