This study was undertaken to examine the effect of different pedalling cade
nces upon various physiological responses during endurance cycling exercise
. Eight well-trained triathletes cycled three times for 30 min each at an i
ntensity corresponding to 80% of their maximal aerobic power output. The fi
rst test was performed at a freely chosen cadence (FCC); two others at FCC-
20% and FCC+20%, which corresponded approximately to the range of cadences
habitually used by road racing cyclists. The mean (SD) FCC, FCC-20% and FCC
+20% were equal to 86 (4), 69 (3) and 103 (5) rpm respectively. Heart rate
(HR), oxygen uptake ((V) over dot O-2), minute ventilation ((V) over dot(E)
) and respiratory exchange ratio (R) were analysed during three periods: be
tween the 4th and 5th, 14th and 15th, and 29th and 30th min. A significant
effect of time (P<0.01) was found at the three cadences for HR, (V) over do
t O-2. The (V) over dot(E) and R were significantly (P<0.05) greater at FCC
+20% compared to FCC-20% at the 5th and 15th min but not at the 30th min. N
evertheless, no significant effect of cadence was observed in HR and (V) ov
er dot O-2. These results suggest that, during high intensity exercise such
as that encountered during a time-trial race, well-trained triathletes can
easily adapt to the changes in cadence allowed by the classical gear ratio
s used in practice.