'''Udarnik''' ({{lang-rus|уда́рник|p=ʊˈdarnʲɪk}}; jamak Inggris '''udarniks''' atau '''udarniki'''), juga dikenal sebagai '''tenaga kerja kejut'''<ref>Moskvin, V.D., 1970. Development of socialistic competition and the introduction of the Saratov system of defectless {{sic}} production at the Volga-Don chemical combine. ''Chemistry and Technology of Fuels and Oils, 6''(3), pp.190-192.</ref> oratau '''striketenaga workerkerja tempur''' (collectivelysecara kolektif knowndikenal assebagai '''shockbrigade brigadeskejut'''<ref name="Siegelbaum1990">{{cite book|author=Lewis H. Siegelbaum|title=Stakhanovism and the Politics of Productivity in the USSR, 1935-1941|url=https://books.google.com/books?id=tFO2JAuI1WkC&pg=PA51|date=29 June 1990|publisher=Cambridge University Press|isbn=978-0-521-39556-4|page=51}}</ref> atau '''tim buruh kejut'''<ref>{{cite book|title=Asia and Africa Today|url=https://books.google.com/books?id=NwgLAQAAMAAJ|year=1991|publisher=Asia and Africa Today|page=464}}</ref>) adalah seorang tenaga kerja yang sangat [[prduktivitas tenaga kerja|produktif]] di [[Uni Soviet]], [[Blok Timur]] dan negara-[[negara komunis]] lainnya. Istilah tersebut berasal dari istilah "udarny trud" yang artinya "buruh antusias, superproduktif".<ref>{{cite book|title=Art and Its Global Histories: A Reader|url=https://books.google.com/books?id=CPUtDwAAQBAJ|date=16 June 2017|publisher=Oxford University Press|isbn=978-1-5261-1992-6|page=309}}</ref>
