Functional diagnostics is one of the most important areas of sports medicine, which plays an increasingly role in selection of athletes, optimisation of training, early diagnostics and prophylaxis of sports pathology. Functional condition of the body undergoes constant changes under the influence of a number of factors. The differences may be considerable and pose problems related to the recruitment of athletes to teams in game sports and in individual sports. Physical ability is determined by the quality of external breathing and cardiovascular functions and by peculiarities of metabolism related to the tissue breathing and transport of substrates. In qualitative assessment of these phenomena one must relate the parameters of the individual's functional conditions to the required or desired values, i.e. norms. On the other hand, there exist no norms for a comprehensive evaluation of the Lithuanian persons' physical capacity and breathing system and metabolic function capacity including residents going in for sports. It is not clear whether one may rely upon the nomograms drawn up by foreign authors because they may not be applicable to Lithuanian athletes for a number of possible reasons: differences in training methods, regional cultural environment (differences in energy requirements in daily life), nutritional aspects, even demographic peculiarities taking into account limited assimilation level and small number of inhabitants. It has been established that the maximum oxygen uptake indicators reflecting the body's dynamic potential are different in elite athletes when evaluated during a standard ergo metric test. The aerobic capacity is determined by all links in the oxygen transport chain, since both heart rate (HR) and breathing indicators (VE-ventilation volume, PEF-peak expiratory flow and RR-respiratory rate) are characterised by equally good correlation with the oxygen uptake indicators and high determination coefficients (all r > 0.95, R2 > 95%, p < 0.01).