Koshi ga Hikui "low-waisted"

It's probably fair to say that Japanese are preccupied with hierarchies. Status is indicated physically by one's posture in relation to others. To bend a little, to lower one's head, or to bow a deep bow is to position oneself vis-a-vis a person of higher rank. Thus, koshi ga hikui is a complement-especially to one who, by virtue of wealth or fame, has attained high status.