In the terminology of the Soviet Union, the Eastern Bloc, and other communist countries, an udarnik (/uːˈdɑːrnɪk/,[1] plural udarniks or udarniki; Russian: уда́рник, IPA: [ʊˈdarnʲɪk]), also known in English as a shock worker[2] or strike worker (collectively known as shock brigades[3] or a shock labor team[4]) is a high productivity worker. It derived from the expression "udarny trud" for "superproductive, enthusiastic labor".[5]