Gavarry O.,University of Toulon |
Aguer C.,Institute Of Recherche Of Lhopital Montfort |
Delextrat A.,Oxford Brookes University |
Lentin G.,Unite Mediterraneenne de Nutrition |
And 2 more authors.
Journal of Sports Sciences | Year: 2015
Abstract: The purpose of this study was to determine the substrate oxidation rate and the exercise intensity at which maximal lipid oxidation and ventilatory threshold (VT) occur in obese (BMI: 36.6 ± 6.3 kg · m−2) and normal-weight adolescent girls (BMI: 18.7 ± 1.6 kg · m−2) aged 14–18 years. Substrate oxidation rate was determined by gas exchange using an incremental field test involving walking. Body composition was assessed by bioelectrical impedance. Carbohydrate oxidation rates were significantly higher in obese than in normal-weight girls at speeds ranging from 4 to 6 km · h−1 (P < 0.05), whereas no significant differences were observed between groups regarding lipid oxidation rates. The crossover point of substrate utilisation and the VT were significantly lower in obese than in normal-weight adolescents (P < 0.05). Maximal lipid oxidation rate was observed at 46 ± 15 and 53 ± 15 %E (Formula presented.) O2max in obese and normal-weight adolescents, respectively. At these intensities, the Lipoxmax was significantly lower in obese than in normal-weight girls (6.7 ± 2.3 versus 8.9 ± 3.5 mg · min−1 · kg−1 FFM, P < 0.05, 95% CI: −3.7 to −0.7, d = −0.74). The present results have implications in designing interventions to promote lipid oxidation and energy expenditure during walking in severely obese adolescent girls. © 2015 Taylor & Francis.