Virginity is the state of being a virgin (never had sexual intercourse).
What can happen, when a girl does extensive physical exercises like horse riding, gymnastics etc. is that the hymen stretches or is torn. As it does when she is penetrated for the first time. But that is only a physical effect and not the definition of 'virginity'.

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“You become responsible forever for what you have tamed”. Antoine de Saint-Exupéry