Abstract des Autors

In short distance triathlon competition heart rates of 170-180 beats/min and average lactate concentrations of 7-10 mmol/l are reached in all three disciplines. The average exercise intensity is, therefore, well above the aerobic-anaerobic threshold. In comparison long distance triathletes perform competition with an average heart rate of 150-155 beats/min and lactate concentrations of 2-3 mmol/l, so that cardiocirculatory and metabolic stress is considerably lower and comparable to that of a marathon runner. In spite of increasing professionalism in triathlon sports in the last few years, the current world class triathletes have performance deficits of approximately 10-13% compared to the specialists in all three disciplines. Triathletes are also still not able to meet the sum of their best times in the three single disciplines in competiton after subtracting the amount of time spent in the transition area. The pulmonary gas exchange is not a performance limiting factor for high endurance trained triathletes under physiological conditions. Compared to the dimensions of the cardiocirculatory system of untrained persons the total heart volume is maximal 70-80% increased; furthermore approximately 45-50% larger cross sectional areas of the arterial vessels can be found in extreme cases. The total blood volume is increased approximately 30-45% after long-term intensive endurance training while the plasma volume responds with an increase of approximately 50-60%. Endurance trained skeletal musculature presents an approximately 15% increased capillary density as well as a twofold higher density and an approximately 35% larger size of the mitochondria. It was shown that the phenotypical VO2max values are determined up to 50% by genetics. On the other hand VO2max can be increased by approximately 30-50% under optimal training conditions. The different peak oxygen uptake (VO2peak) in the three triathlon disciplines, are determined and limited by the maximal mitochondrial O2-exhaustion of the various muscle groups required for swimming or cycling or running. Verf.-Referat