¿Qué verbo se usa par la acción de mover los pedales de una bicicleta? ¿pedalear?
To further clarify iheartL&O's reply, "to pump" in this context means "to pedal." It's referring to the legs working hard and fast to pedal, moving up and down as if working a pump.I don't see the word "pedal" in your sentence. Are you translating the verb "to pedal" or the verb "to pump"?