Energy substrate utilization with and without exogenous carbohydrate intake in boys and men exercising in the heat

EFFECTS OF A SMALL-SIDED SOCCER PROGRAM ON HEALTH PARAMETERS IN OBESE CHILDREN

ABSTRACT Introduction: Childhood obesity is increasing and, as a consequence, it generates health complications resulting from sedentary behavior and low levels of physical fitness. There are few studies involving children, metabolic and cardiorespiratory profiles, and soccer. Objective: The purpose was to measure the effects of a 12-week recreational small-sided soccer program on cardiometabolic risk and individual responses to cardiometabolic risk factors in overweight or obese boys. Methods: Thirteen boys aged 8-12 years (34.9±11.6% body fat) participated in a 12-week recreational small-sided soccer training program with two 80-minute sessions per week at intensities over 80% of the maximal heart rate. Anthropometric characteristics, cardiorespiratory fitness, metabolic profile, individual responses to peak oxygen uptake (VO2peak), maximal workload (Wmax), fasting blood glucose, insulin, HOMA-IR, LDL-C, HDL-C, TC, and TG were measured both pre- and post-training. Results: Considering the individual responses of the participants, recreational soccer training was effective in improving variations in maximum power and exhaustion time, as well as promoting at least one beneficial change in cardiometabolic risk factors in 84% of the overweight or obese children. There were no differences between pre- and post-program anthropometric characteristics, metabolic profiles, or VO2peak values. Conclusion: Twelve-week recreational small-sided soccer programs were able to improve maximal power and anaerobic capacity and maintain cardiometabolic risk factor levels in overweight and obese boys. Level of evidence I; High-quality prospective study (all patients were enrolled at the same stage of disease, with >80% of patients enrolled) .

UEFA expert group statement on nutrition in elite football. Current evidence to inform practical recommendations and guide future research

Football is a global game which is constantly evolving, showing substantial increases in physical and technical demands. Nutrition plays a valuable integrated role in optimising performance of elite players during training and match-play, and maintaining their overall health throughout the season. An evidence-based approach to nutrition emphasising, a 'food first' philosophy (ie, food over supplements), is fundamental to ensure effective player support. This requires relevant scientific evidence to be applied according to the constraints of what is practical and feasible in the football setting. The science underpinning sports nutrition is evolving fast, and practitioners must be alert to new developments. In response to these developments, the Union of European Football Associations (UEFA) has gathered experts in applied sports nutrition research as well as practitioners working with elite football clubs and national associations/federations to issue an expert statement on a range of topics relevant to elite football nutrition: (1) match day nutrition, (2) training day nutrition, (3) body composition, (4) stressful environments and travel, (5) cultural diversity and dietary considerations, (6) dietary supplements, (7) rehabilitation, (8) referees and (9) junior high-level players. The expert group provide a narrative synthesis of the scientific background relating to these topics based on their knowledge and experience of the scientific research literature, as well as practical experience of applying knowledge within an elite sports setting. Our intention is to provide readers with content to help drive their own practical recommendations. In addition, to provide guidance to applied researchers where to focus future efforts.

Endogenous versus exogenous carbohydrate oxidation measured by stable isotopes in pre-pubescent children plus 13C abundances in foods consumed three days prior

PURPOSE

The purposes of the present study were to (a) examine resting metabolism, substrate utilization, and endogenous versus exogenous carbohydrate (CHO) oxidation before and after 30-g rapidly-digesting carbohydrate (RDC) ingestion using indirect calorimetry and breath test analysis of stable isotope concentrations in pre-pubescent children and (b) report the 13C abundances in foods consumed for three days prior.

METHODS

Nineteen children (n = 10 boys, n = 9 girls) at Tanner stage I or II participated (mean age ± 95% CI = 9.84 ± 0.77 y) in this study. Food was administered to the children for three days preceding their scheduled breath tests. Breath tests and indirect calorimetry were performed after an 8-h fast before and 60 min following consumption of a 30-g simple RDC drink consisting of maltodextrin and sucrose. Open circuit spirometry and indirect calorimetry monitored resting metabolism and CHO oxidation. Separate breath samples were taken every 15 min. Samples of all foods and breath samples were analyzed for 13C and 12C abundances with a stable-isotope mass spectrometer.

RESULTS

13C in expired breath samples were -23.81 ± 1.64‰ at baseline and increased every 15 min after consumption of the CHO drink (p < 0.001-0.009). Cumulative total, endogenous, and exogenous CHO utilization increased during the post-prandial period (p < 0.001). Endogenous CHO oxidation was consistently greater than exogenous CHO oxidation (p < 0.001-0.002).Blood glucose was elevated from baseline at 30- and 60-min post-prandial (p < 0.001). Insulin did not change over time (p = 0.184).

CONCLUSIONS

The foods provided during the 3-day controlled diet effectively minimized 13C variation prior to metabolic testing. The 13C abundances of foods reported herein should serve as practical recommendations to reduce 13C intake before breath tests. While endogenous CHO oxidation remained greater in proportion to exogenous CHO oxidation, these findings suggest that even a relatively small amount of RDC can increase exogenous CHO oxidation and blood glucose in normal-weight children. To further examine shifts in endogenous versus exogenous CHO utilization, we recommend that future studies take steps to minimize 13C variation before breath tests and examine changes in substrate metabolism at rest and during exercise in normal weight and overweight pre-pubescent children.

CLINICAL TRIAL REGISTRATION NUMBER

NCT03185884.