Comparison of three type of muscle glycogen loading interventions using a very-high-carbohydrate diet in an elite male racewalker: a case report
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Published:2023-03-31
Issue:1
Volume:27
Page:047-054
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ISSN:2733-7545
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Container-title:Physical Activity and Nutrition
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language:en
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Short-container-title:Phys Act Nutr
Author:
Kondo Emi,Takai Eri,Sagayama Hiroyuki,Takahashi Hideyuki
Abstract
[Purpose] Muscle glycogen storage before a race is necessary for endurance athletes to achieve the best performance. Generally, the recommended carbohydrate intake for preparation over 90 min of the race is 10–12 g·kg-<sup>-1</sup>·day-<sup>-1</sup>. However, it remains unclear whether an elite athlete with an already high-carbohydrate diet can further increase muscle glycogen through a very-high-carbohydrate intake. Therefore, we compared the effects of three types of glycogen loading in a 28-year-old male athlete who belongs to the top 50 racewalkers in the world, consuming a daily energy intake of 4507 kcal and a carbohydrate intake of 12.7 g·kg-<sup>-1</sup>·day-<sup>-1</sup>.[Methods] The racewalker consumed very-high-carbohydrate diets three times for 2 days each, 13.7 g·kg-<sup>-1</sup>·day-<sup>-1</sup> for trial 1, 13.9 g·kg-<sup>-1</sup>·day-<sup>-1</sup> for trial 2, and 15.9 g·kg-<sup>-1</sup>·day-1 for trial 3. Muscle glycogen concentrations in the anterior (vastus lateralis and vastus intermedius) and posterior thighs (semimembranosus, semitendinosus, and biceps femoris) were measured using carbon-13 magnetic resonance spectroscopy.[Results] Muscle glycogen concentrations in both the anterior and posterior thighs increased in all trials, particularly in trial 3. Body mass also increased by 1.5 kg in trials 1 and 2 and by 1.8 kg in trial 3 before and after the trials. The participant felt satiated throughout the day and experienced stomach discomfort during trial 3.[Conclusion] We found that a 2-day very-high-carbohydrate diet and tapering of training could further increase the muscle glycogen concentration in athletes. However, we speculated that 15.9 g·kg-<sup>-1</sup>·day-<sup>-1</sup> carbohy
Funder
Japan Society for the Promotion of Science
Publisher
Korea Society for Exercise Nutrition
Subject
Nutrition and Dietetics,Physical Therapy, Sports Therapy and Rehabilitation,Orthopedics and Sports Medicine,Physiology,Health (social science)