Objectives: To investigate the impact of fast-start, steady or slow-start strategies of the running fraction in sprint triathlon on oxygen consumption, perception of fatigue and blood lactate.Design: Thirteen male triathletes (age; 36.4 ± 10.8 yy, height 174.8 ± 7.9 cm, body mass 70.6 ± 11.1 kg; V'O2max 62.4 ± 8.9 ml min-1 kg-1; mean ± SD) attended the laboratory five times in order to complete two incremental tests and three subsequent cycle-run sessions.Methods: Three experimental randomized sessions with different effort distribution were compared. The intensities of the 1st running kilometer were set at 95%, 100% and 105% of the second ventilatory threshold for slow, continuous and fast start protocol respectively. Measurement of ventilatory variables, blood lactate and ratings of perceived exertion were collected throughout all sessions.Results: A meaningful difference was found between the slow versus fast start protocol in V'O2 (SE = 0.58, P = 0.0005), BLa- (SE = 0.21, P = 0.0097), HR (SE = 1.23, P = 0.0011) and RPE (SE = 2.83, P = 0.0047) values. No differences in-between protocols were found at the end of the running bout whatever the condition.Conclusions: Differences in physiological parameters were found between protocols during the first kilometer, not at the end of exercise. The fast start appears to be more correct and useful for performance in racing setting and may be used as a strategy without impacting the remaining running bout in ecological setting. [ABSTRACT FROM AUTHOR]