20191003 Seminar

Metabolic and Fatigue Profiles Are Comparable Between Prepubertal Children and Well-Trained Adult Endurance AthletesSebastien RATEL

Summary : It is well acknowledged that prepubertal children have smaller body dimensions and a poorer mechanical (movement) efficiency, and thus a lower work capacity than adults.

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It is well acknowledged that prepubertal children have smaller body dimensions and a poorer mechanical (movement) efficiency, and thus a lower work capacity than adults. However, the scientific evidence indicates that prepubertal children have a greater net contribution of energy derived from aerobic metabolism in exercising muscle and reduced susceptibility to muscular fatigue, which makes them metabolically comparable to well-trained adult endurance athletes. For example, the relative energy contribution from oxidative and non-oxidative (i.e. anaerobic) sources during moderate-to-intense exercise, the work output for a given anaerobic energy contribution, and the rate of acceleration of aerobic metabolic machinery in response to submaximal exercise are similar between prepubertal children and well-trained adult endurance athletes. Similar conclusions can be drawn on the basis of experimental data derived from intramuscular measurements such as type I fibre percentage, succinate dehydrogenase enzyme activity, mitochondrial volume density, post-exercise phosphocreatine resynthesis rate and muscle by-product clearance rates (i.e. H+ ions). On a more practical level, prepubertal children also experience similar decrements in peak power output as well-trained adult endurance athletes during repeated maximal exercise bouts. Therefore, prepubertal children have a comparable relative oxidative contribution to well-trained adult endurance athletes, but a decrease in this relative contribution occurs from childhood through to early adulthood. In a clinical context, this understanding may prove central to the development of exercise-based strategies for the prevention and treatment of many metabolic diseases related to mitochondrial oxidative dysfunction (e.g. in obese, insulin-resistant and diabetic patients), which are often accompanied by muscular deconditioning during adolescence and adulthood.

Biography : Sébastien Ratel received a Master Degree in Sport sciences in 1998 and his Ph.D. in Exercise Physiology in 2001 from the University of Blaise Pascal, Clermont-Ferrand, France. For one year, he worked in the Children’s Health and Exercise Research Centre in Exeter, UK. Since 2004, he is back in France as an Associate Professor in the laboratory of metabolic adaptations during exercise in physiological and pathological conditions (EA 3533, AME2P). He is strongly fascinated by the effects of growth and maturation on metabolic and neuromuscular responses during high-intensity exercise. His current research interests include muscle fatigue and recovery from high-intensity exercise in children. He is author or co-author of more than 100 full papers in peer review journals and book chapters. He is also co-editor of a textbook entitled “Human muscle fatigue” (Routledge, 2009), and author of two French books entitled “Enfant et Activité Physique” (Désiris, 2014) and “Préparation Physique du Jeune Sportif” (Amphora, 2018).

Presentation : Not available