1
general::
Phrase(s): get the lead out [and] shake the lead out
Inf. to hurry; to move faster. (This originally refers to getting lead weights (used in exercise) off so you can move faster.) • Come on, you guys. Get the lead out! • If you’re going to sell cars, you’re going to have to shake the lead out.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Also, get the lead out of one's feet or pants. Hurry up, move faster. For example, Get the lead out of your pants, kids, or we'll be late, or, even more figuratively, Arthur is the slowest talker? he can't seem to get the lead out and make his point. This expression implies that lead, the heaviest of the base metals, is preventing one from moving. [Slang; first half of 1900s]
American Heritage Idioms