[SunkenCiv]

[snip] In the comedy Lysistrata by the Athenian playwright Aristophanes, a group of Athenian women crowd round a Spartan woman called Lampito. ‘What a gorgeous creature,’ they say. ‘What healthy skin, what firmness of physique.’ And one of them adds, ‘I’ve never seen a pair of breasts like that.’ To which Lampito proudly responds, ‘I go to the gym. I make my buttocks hard.’ [unsnip]

http://www.channel4.com/history/microsites/H/history/n-s/spartans2.html

[Verginius Rufus]

That is from lines 81 and 82 of the Lysistrata (going by the line numbers in the Greek text).

Jeffrey Henderson's translation in the new Loeb edition reads:

"It's true, I think, by the Twin Gods. I do take exercise, and I jump-kick my butt."

Lampito's words are in Doric, or at any rate an Athenian's notion of Doric Greek. She uses the word gymnaddomai which presumably is equivalent to the Attic gymnazomai meaning "I exercise for myself" or "I practice" (the basic meaning is to train naked--from gymnos naked, unclad).