Triathlon is a very complex sport, as the athlete has to master the characteristics of three sports (swimming, cycling and running), and the tasks of coaches are increased by the need to get the most out of all three. This sport improves endurance, has a positive effect on muscle development, movement coordination, breathing, and circulation. For talent identification factors determining the performance in triathlon are essential (physiological, anthropometric, psychosocial and tactical factors). Scientific literature concerning performance in triathlon sport is rather scarce. Although there are some studies in this field, there is little comprehensive literature analyzing training of youth athletes. The aim of our research was (i) to conduct a targeted literature review of the body composition and performance of youth triathletes and (ii) comparing results with those of elite adults, (iii) determining factors playing a prominent role in the selection and performance of triathletes. The results of our research reveal that factors like the appropriate competition age (approx. 28-30 years for both sexes), anthropometric parameters (it is necessary to take into account the distance the athlete covers) and performance criteria (the most important is VO2max) are essential for successful selection and subsequent success. In the world of triathlon constant regulatory changes and the need to adapt new competitive demands necessitate keeping our knowledge up to date.

The aim of our research was to find a way, based on international experience, to examine the training method that can be successfully used in youth age groups, and as a consequence, to increase the effectiveness of the sport of triathlon. In Hungary, the methods of preparing the younger age group (10-18 y) are not yet uniform. Hungarian triathletes do not dominate at the international level, neither in the junior age groups nor in the elite field. Two basic methods "fight" each other in Hungary, the so-called "threshold" training (training at the anaerobic threshold), the effectiveness of which has been proven by numerous studies in various sports. The aim of this study was to analyze the effectiveness of “Polarized” (Pol) and “Threshold” (TR) training in youth ages (15-18y). Male youth triathlete subjects taking part in systematic training (n=10, n(Pol) =5; n(TR)=5) were studied. Performance (time), physiological data from spiroergometry (vita maxima) tests and anthropometric features were measured in this longitudinal study (3 years). Performance improvement, relative oxygen uptake (rVO2max) and aerobic time significantly increased (p<0.05) in Pol group, while differences of their anthropometric features did not change significantly during the research. No significant changes were found in any parameters of TR group. There were no significant differences of anthropometric and cardiovascular (Heart Rate) characteristics between the two groups in any assessment. The differences of rVO2max and relative aerobic capacity at the anaerobic threshold were significant in the Pol group (p<0.05) at the second and third measurements. Performance improvement and time in aerobic zone increased more in the Pol group than in the TR group (p<0.05). The Pol training method proved to be more effective than the TR training of the studied group.