pump iron

verb

pump iron

verb

1

Bodybuilding, Hobbies, Lifestyle, Sports 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.
For years now, Arnold Schwarzenegger has made the talk-show rounds telling audiences that pumping iron is better than sex. No wonder it took him so long to find a bride.1987 September, Robert McKay, “The National Standard”, in Cincinnati Magazine, page 104:

1 more example

Early strongmen like Eugen Sandow (the model for the Mr. Olympia trophy) and late-1800s "Iron-Master" Arthur Saxon (who wrote the book on one-hand overhead moves) kicked off the first movement of guys pumping iron.2026, Greg Presto, “Timeless Gains”, in Men's Health, volume 41, number 2, page 14:

Entry derived from the Wiktionary, under licence CC BY-SA 4.0 — list of authors.