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purpose of this study was to determine if differences in oxygen uptake
kinetics and oxygen deficit existed between normal weight and severely
overweight adolescent girls. Subjects included 10 normal weight and
8 severely overweight girls. The participants performed a leg cycling
VO2 peak test and a constant load leg cycling test at 80%
of the ventilatory threshold (T-vent). In the constant workload test
O2 kinetics as indicated by Phase I (VO2 L at
20 sec) and Phase II time constants (t) were determined. Also, the O2 deficit (VO2
L) was measured. As expected significant differences were noted in
body composition and VO2 peak relative to mass with normal
weight body mass averaging 55.3 ± 7.0 kg, severely overweight 90.5
± 18.0 kg, % fat normal weight 27.3 ± 3.9%, severely overweight 49.7
± 4.9% and VO2 peak (ml·kg-1·min-1)
normal weight 32.0 ± 2.7 and severely overweight 22.0 ± 5.3. VO2
peak (l·min-1) and T-vent (%VO2 max) were similar
between groups. Results revealed similar O2 kinetic responses
between groups; phase I kinetics normal weight 0.72 ± 0.15 L; severely
overweight 0.75 ± 0.13L, phase II (t) normal weight 41.5 ± 21.3 sec; severely overweight
33.9 ± 22.7 sec. However, the O2 deficit was significantly
higher in the severely overweight (0.75 ± 0.15L) when compared to
the normal weight group (0.34 ± 0.13L). Correlations ranged from r
= -0.15 to 0.51 between VO2 peak (L·min-1) or
fat weight and phase I, t and O2 deficit. These data generally support
previous research concerning the independence of O2 uptake
response and body size.
KEY
WORDS: O2 kinetics, O2 deficit, severely
overweight, female, youth.
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