leg (n.) Look up leg at Dictionary.com
late 13c., from a Scandinavian source akin to Old Norse leggr "leg, bone of the arm or leg," from Proto-Germanic *lagjaz, with no certain ulterior connections, perhaps from a PIE root meaning "to bend" [Buck]. Compare German Bein "leg," in Old High German "bone, leg." Replaced Old English shank. Of furniture supports from 1670s. The meaning "a part or stage of a journey or race" (1920) is from earlier sailing sense of "a run made on a single tack" (1867), which was usually qualified as long leg, short leg, etc. Slang phrase shake a leg "dance" is attested from 1881. To be on (one's) last legs "at the end of one's life" is from 1590s.
leg (v.) Look up leg at Dictionary.com
"to use the legs; walk or run," c.1500 (from the beginning usually with it); from leg (n.).