Verb
pump iron (third-person singular simple present pumps iron, present participle pumping iron, simple past and past participle pumped iron)
(idiomatic) To lift weights; to engage in weight or strength training.
Her upper body strength has been improving since she started pumping iron at the gym.
I'm kind of a jock. I sail, I ride a bike, I hike, I pump iron. I just love to be active. Laura Schlessinger