# chapter 12. Laban's concept of effort and his work in the 1940s and 1950s Effort was at the centre of Laban's thinking about movement behaviour in this Period.. He was writing about movement qualities in the 1920s when the four motion factors were : Force, Space, Time, Flight. He called this aspect of movement analysis as 'Eukinetics': the Greek prefix 'eu-' means teh senses of 'good', 'well' ..