Instability of theoretical rate dependencies of the stress intensity factor and fracture energy is considered from the point of view of force and energy limiting criteria formulated on the basis of the concepts of the structural-temporal approach. Applying both approaches separately, the water saturation effect on dynamic stress intensity factor and dynamic fracture energy is predicted. Using the dynamic fracture of sandstone as an example, the incubation times as a characteristic of the rate sensitivity of the material determined by the force and energy fracture are compared.