 The model and ballerina Lyn Marshall was chosen to demonstrate the poses under his instruction, on the grounds that "any reasonably fit person" could benefit from yoga, even though, as Newcombe remarks, Marshall was, as a trained dancer, hardly average.Marshall went on to publish a series of illustrated guides to yoga, including "Wake up to Yoga" (1975) and "Keep up with Yoga" (1976).Newcombe estimates that the number of people, mainly middle-class women, practising yoga in Britain rose from about 5000 in 1967 to 50,000 in 1973 and 100,000 by 1979; most of their teachers were also women.