[Growth models and growth spurt in the human].

Growth of man differs basically from that of all animals - perhaps except some species of primates - by demonstrating a puberal growth spurt. This behaviour is well known but was hardly ever analyzed in a mathematical manner. The growth spurt is indeed difficult to grasp and this all the more as it shows varying forms of appearance. This becomes evident by the investigation of height values for normal and growth-restricted children as is the case with genetic diseases. From these variants, PELZ and SAGER came to the conclusion of setting up differentiated forms of growth spurts with adequate definitions in mathematical formulation. In this contribution, the models of human height growth and height velocity as practiced at Zurich (working group PRADER), London (working group TANNER) and Rostock (PELZ, SAGER, EYERMANN) are recalled and scrutinized as to the applicability of the new definitions. After the somewhat difficult comparisons of the model structures meditations are focussed at the proposals for the definition of the duration and the intensity of the growth spurt leading to quite different conceptions. Relative agreement is present for the time of the onset of the spurt whilst larger differences appear for the end of the puberal phase. A complete coincidence can hardly be reached but at least some light is thrown on this intricate problem by analyzing the different points of view.