Abstract des Autors

Background: To report physiological profiles, and investigate the relationship between selected physiological variables and cycling performance in ultra-endurance triathletes. Methods: Participants: ten male (mean+/-SD, age; 32+/-5 years) ultra-endurance triathletes participated in the study. Physiological profiles were compared with 10 male age-matched control subjects. Measures: left ventricular structure (wall thickness (LVPWd), internal diameter (LVIDd), and mass (LVM)) and function (diastolic filling, fractional shortening, and stroke volume (SV)) were assessed using standard M-Mode, 2D, and Doppler echocardiography. Maximal and submaximal exercise gas exchange responses were measured on-line during a maximal ramping cycle-ergometer exercise test. Results: Ultra-endurance triathletes demonstrated significantly larger LVPWd, LVIDd, LVM, SV, VO2max, anaerobic threshold (AT), and power to body-mass ratio compared with controls. Cycling performance for both lronman and half Ironman were significantly correlated with LVPWd, LVM, and SV. LVIDd was significantly correlated to Ironman cycle time alone. Oxygen consumption (VO2) at AT, percentage of VO2max at AT, and peak power to body-mass ratio were significantly correlated to bike finish time in the half Ironman, but not Ironman. Conclusions: The correlation between cycling performance, LVM and SV suggests that the more conditioned athletes may be better able to maintain a high cardiac output during prolonged cycling. Submaximal gas exchange responses are predictors of cycling performance for the half-lronman but not the Ironman. These results suggest that other factors including the longer duration swim prior to the cycling component, may impact upon cycle performance. Verf.-Referat