Dvb. James et Jh. Doust, Oxygen uptake during high-intensity running: response following a single bout of interval training, EUR J A PHY, 79(3), 1999, pp. 237-243
Citations number
32
Categorie Soggetti
Physiology
Journal title
EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY
Elevated oxygen uptake ((V) over dot O-2) during moderate-intensity running
following a bout of interval running training has been studied previously.
To further investigate this phenomenon, the (V) over dot O-2 response to h
igh-intensity exercise was examined following a bout of interval running. W
ell-trained endurance runners were split into an experimental group [maximu
m oxygen uptake, (V) over dot O-2max 4.73 (0.39) l.min(-1)] and a reliabili
ty group [(V) over dot O-2max 4.77 (0.26) l.min(-1)]. The experimental grou
p completed a training session (4 x 800 m at 1 km.h(-1) below speed at (V)
over dot O-2max, with 3 min rest between each 800-m interval). Five minutes
prior to, and Ih following the training session, subjects completed 6 min
30 s of constant speed, high-intensity running designed to elicit 40% Delta
(where Delta is the difference between (V) over dot O-2 at ventilatory thr
eshold and (V) over dot O-2max; tests 1 and 2, respectively). The slow comp
onent of (V) over dot O-2 kinetics was quantified as the difference between
the (V) over dot O-2 at 6 min and the (V) over dot O-2 at 3 min of exercis
e, i.e. Delta(V) over dot O2(6-3) The Delta(V) over dot O2(6-3) was the sam
e in two identical conditions in the reliability group [mean (SD): 0.30 (0.
10) l.min(-1) vs 0.32 (0.13) l.min(-1)]. In the experimental group, the mag
nitude of the slow component of (V) over dot O-2 kinetics was increased in
test 2 compared with test 1 by 24.9% [0.27 (0.14) l.min(-1) vs 0.34 (0.08)
l.min(-1), P < 0.05]. The increase in Delta(V) over dot O2(6-3) in the expe
rimental group was observed in the absence of any significant change in bod
y mass, core temperature or blood lactate concentration, either at the star
t or end of tests 1 or 2. It is concluded that similar mechanisms may be re
sponsible for the slow component of (V) over dot O-2 kinetics and for the f
atigue following the training session. It has been suggested previously tha
t this mechanism may be linked primarily to changes within the active limb,
with the recruitment of alternative and/or additional less efficient fibre
s.