What is a summary of the poem "Breaking Out" by Marge Piercy?

Marge Piercy's "Breaking Out" was was initially published in the Harbor Review in 1984. It reflects two themes or attitudes common in Piercy's work: feminism and social activism. As is also common in her work, the poem has autobiographical elements, reflecting Piercy's own upbringing in a working-class family during the Depression.
The poem is written in the first person in past tense and looks backward at an event that occurred when the narrator was eleven years old, an event that the narrator considers a turning point in her transformation from life as a passive and subordinate child to an independent adolescent. The narrator's self-assertion rejects her subordinate role as both child and female, identifying her own oppression by her parents with the way her mother appears oppressed by patriarchal society.
The poem is written in free verse, divided into stanzas of irregular length. The lines are of approximately equal length, some being end-stopped and some enjambed. The language is fairly simple, realistically embodying the voice and viewpoint of a young girl.
The poem begins with a description of a mangle (a device used for ironing) and a vacuum cleaner. For the narrator, these are both symbols of her mother's oppression and the oppression of women in general, a life she herself sees as empty and futile and compares to the task of Sisyphus, which she learned about in school. Reading is portrayed as an escape from and mode of resistance to the drudgery of housework.
Towards the middle of the poem, we learn that both the narrator's father and mother beat her with a wooden stick when she had been "judged truly wicked." She describes the beatings and her injuries from them.
The final part of the poem describes the day she asserts herself by taking the stick and breaking it. Although this did not mark an end to the beatings, it changed the way she thought about herself in relationship to her family and led her to make a resolution: 

I would not be Sisyphus, there were things that I should learn to break.