Vladimir Bazarov (1874-1939) tried to construct a monistic theory of cycles and crises on the basis of energy. His analysis of energy principles leads him, in a second step, to put the emphasis on productive forces and labour productivity, whose behaviour plays a determining role in the manifestation of both the cycle and the crisis. Finally, in empirical and statistical terms, the dynamics of labour productivity and of most of the economic series in Bazarov's model are considered to be the result of a moving stochastic equilibrium (different from the purely mechanic dynamic equilibrium).