You always encourage each other -- sometimes with a bit of sass.

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She gives you the courage to finally try that crazy new fitness class you've always been too intimidated to try -- and the two of you end up totally owning the class from the front row.

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Your stretching routine starts to resemble something out of the "Kama Sutra" or you regularly show off with acrobat-like moves when prepping for your workout together.

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You get crazy in sync with one another, so much so that people think you have some sort of weird ESP connection.

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She's always on your back to do just one more rep.

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