Modellierung von Energiestoffwechsel und Laktatkinetik in Hinblick auf Design und Optimierung von Leistungstests

In the area of diagnosis of physical performance blood lactate concentration is a well established indicator of the relative contribution of anaerobic energy liberation to total energy requirements. For the quantification of physical performance capacity in most cases the socalled "aerobic-anaerobic transition" - determined according to different procedures - is used. Via a description of the basic mechanisms characterizing lactate kinetics using a math. model we attempted to etablish the basis for an extended performance diagnosis. The model we used was structured as a two compartment model with lactate production dependend on the work load. Lactate elimination was modeled as a function of oxygen consumption. The identification of the 7 free model parameters was performed on the basis of two different work load protocols using the gradient procedures according to Gauss and Levenberg/ Marquardt. Employing this approach we were able to identify an individual set of parameters for every volunteer. This set of parameters was subsequently used to simulate a modified work load protocol for validation purposes. Varying the initial values for the set of parameters to identify had almost no influence onto the finally identified values of the parameters, the procedure according to Gauss proved to be more robust against badly chosen initial values.