Members of the leggy-kick-line precision dance group, the Rockettes, must be between 5’6″ and 5’10 1/2″ tall (measurements will be taken). Rockette candidates must be proficient in jazz and tap. We also believe they must meet certain leg/torso ratios and can be fired if they gain or lose too much weight, but I can’t confirm this on the interweb.

The Rockettes were originally named the Rockets, then were brought to New York by famed 1920s showman Samuel Lionel “Roxy” Rothafel, who renamed them the Roxyettes. They later were renamed the Rockettes.

Source: Radio City Christmas Spectacular starring the Rockettes, then a wiki to confirm