To optimize training and determine performance factors in a triathlon, we need to know the bioenergetic requirements and physiological response during competition. However, the physiological demands for an entire triathlon in relation to the individual metabolic capacities of triathletes have not been characterized yet. Here we aimed to provide the first comprehensive description of the physiological demands of an entire ultra-endurance triathlon. Methods: Ten well-trained ultra-endurance triathletes (mean ± SD: age 37.1 ± 5.3 years, mass 74.9 ± 6.4 kg, height 1.74 ± 0.06 m, BMI 24.7 ± 1.8 kg/m2, VO2peak = 4.92 ± 0.5 l/min) participated in the study. To investigate exercise intensity, heart rate (HR) was recorded during a competition using portable monitors. Before the ultra-endurance triathlon, subjects performed graded exercise tests involving cycle ergometry, treadmill running and swimming to determine peak oxygen uptake (VO2peak) and heart rate corresponding to the first and second ventilatory thresholds (VT1 and VT2). Results: The HR in the swimming stage was closely related to the HR at VT1 (r = 0.77, P = 0.01) and related to the HR at VT2 (r = 0.68, P = 0.03). The HR in the cycling stage was not related to the HR at VT1 and VT2. The HR in the running stage was related to the HR at VT2 (r = 0.64, P = 0.048) but not to the HR at VT1. The HR during the swimming stage was significantly higher than the HR at VT1 (P = 0.00), but there were no differences between the HR during the swimming stage and the HR at VT2. The HR in the cycling and running stages were significantly lower than the HR corresponding to VT1 (P = 0.01 and P = 0.01, respectively) and VT2 (P = 0.00 and P = 0.00, respectively) Discussion: This study is the first to characterise the relative intensity (HR related to ventilatory thresholds) during the race of the three stages of a triathlon. The differences in HR between the swimming and cycling stages correlate with the marathon time and the overall time. The triathletes with the greatest difference in HR in the swimming stage and HR during the cycling stage had the worst cycling times. As stated in Laursen et al. (2005), working beyond capacity in one stage makes recovery difficult, leading to worse performance in the next stage. This correlation can also be seen in HR differences for the swimming and running stages, as a large difference in values is associated with a reduction in the marathon time.
© Copyright 2012 17th Annual Congress of the European College of Sport Science (ECSS), Bruges, 4. -7. July 2012. Veröffentlicht von Vrije Universiteit Brussel. Alle Rechte vorbehalten.