They've been working out. They are the largest land crustaceans, reaching about 4 kg in body weight. But they can lift close to 30kg and their pincers can exert 3,300 newtons of force. That's competitive with the maximum force exerted by any terrestrial animal. Only alligator jaws can beat it, and alligators are much bigger animals. So watch your fingers! http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0166108
