The present study was carried out in order to quantify the athlete's e
ndurance impairment after two out of three sequential events of Olympi
c Triathlon (OT). Furthermore the significance of ventilatory threshol
d (Tvent) and peak of oxygen uptake (VO(2)peak) as triathlete's perfor
mance predictors was assessed. Tvent and VO(2)peak were measured in si
x male triathletes performing an incremental treadmill test a week bef
ore an ad hoc triathlon event. The same test was applied immediately a
fter the first two segments of the triathlon (1.5 km swim, 32 km bike)
. VO(2)peak and Tvent measured during the latter test were reduced com
pared to the first test. VO(2)peak decreased from 69 to 64 ml.kg(-1).m
in(-1) and Tvent from 58 to 51 ml.kg(-1).min(-1) (p<0.01), respectivel
y. VO(2)peak and Tvent measured in the first test were well correlated
(P<0.05) to both running and cycling times. The Tvent measured during
the second test was related to the running time but with a higher sig
nificance (p<0.01) than in the first test. The impairment in the endur
ance performance induced by the first two segments of OT is an importa
nt aspect to consider both in training and in race strategy. These res
ults also provide evidence that VO(2)peak and Tvent are good predictor
s of triathlon performance at least in cycling and running events.