Abstract: A method for measuring the mechanical integrity of a collagen network in cartilage and of other extracellular matrices according to applying a known mechanical stress to the sample; measuring a quantity representing hydration of the sample; and providing the extracellular network recoil pressure according to the known applied mechanical stress and the independently determined proteoglycan osmotic pressure corresponding to the hydration. In accordance with an embodiment of the present invention, an in vitro mechanowsmotic titration method for determining the collagen network tension (i.e., recoil pressure) for a given collagen network hydration is used. In accordance with a further embodiment of the present invention, the method may be used for diagnosing and/or monitoring the progression of diseases, such as osteoarthritis, preferably according to the collagen network stiffness, which for example, is shown to be reduced in osteoardritic cartilage compared with normal cartilage.