Exertion testing has an important role in the evaluation of symptoms and readiness to RTA, particularly in youth who are slow to recover. Overall, controlled exertion seemed to lesson symptoms for most youth.

The aim of the current study was to investigate the relationship between the Oxygen Uptake Efficiency Slope (OUES) and traditional measures of cardiorespiratory function in an overweight/obese pediatric sample. Maximal treadmill exercise testing with indirect calorimetry was completed on 56 obese children aged 7-18 years. Maximal OUES, submaximal OUES, VO(2peak), VE(peak), and ventilatory threshold (VT) were determined. In line with comparable research in healthy-weight samples, maximal and submaximal OUES were both correlated with VO(2peak), VE(peak), and VT (r(2)= 0.44-0.91) in the obese pediatric sample. Correlations were also found with anthropometric variables, including height (cm), body surface area (m(2)), body mass (kg), and fat free mass (kg). In comparing our data to a published sample of healthy weight children, maximal and submaximal exercise OUES were both higher in our obese sample. However, when we adjusted for any of body mass (kg), BSA (m(2)), or FFM (kg) the obese children were found to be less efficient. The results of this study suggest the use of OUES to be an appropriate measure of efficiency of ventilation and cardiorespiratory function in obese children, while also showing that our sample of obese children were less efficient on a per kilogram basis when compared with their healthy weight peers.

Protein ingestion is important in enhancing whole-body protein balance in children. The effect of discrete bolus protein ingestion on acute postexercise recovery has yet to be determined. This study determined the effect of increasing doses of ingested protein on postexercise whole-body leucine balance in healthy, active children. Thirty-five children (26 boys, 9 girls; age range: 9-13 y; weight mean ± SD: 44.9 ± 10.6 kg) underwent a 5-d adaptation diet (0.95 g protein ⋅ kg ⋅ d) before performing 20 min of cycling 3 times with a concurrent, primed, constant infusion of [C]leucine. After exercise, participants consumed an isoenergetic beverage (140 kcal) containing variable amounts of bovine skim-milk protein and carbohydrates (sucrose) (0, 5, 10, and 15 g protein made up with 35, 30, 25, and 20 g carbohydrates, respectively). Blood and breath samples were taken over the 3 h of recovery to determine non-steady state whole-body leucine oxidation (Leu) and net leucine balance (Leu). Leu (secondary outcome) peaked 60 min after beverage ingestion and demonstrated a relative dose-response over the 3 h of recovery (15 g = 10 > 5 > 0 g; < 0.001). Leu (primary outcome) demonstrated a dose-response over the 3 h [15 g (24.2 ± 8.2 mg/kg) > 10 g (11.6 ± 4.3 mg/kg) > 5 g (5.7 ± 1.9 mg/kg) > 0 g (-3.0 ± 1.7 mg/kg); all < 0.01] with all conditions different from zero (all 0.001). Over the 3-h postexercise period, Leu was negative with carbohydrate ingestion alone; however, the co-ingestion of carbohydrates and 5 g high-quality dietary protein was sufficient to promote a positive postexercise whole-body protein balance in healthy, active children. Moreover, Leu increased in a dose-dependent manner within the protein range studied. Children should consider consuming a source of dietary protein after physical activity to enhance whole-body anabolism. This trial was registered at clinicaltrials.gov as NCT01598935.

This study supports using a half-body scan methodology for percent fat, total mass, fat mass, lean mass, and BMC as a valid alternative to full-body analysis in obese children and youth.

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