Persistence of supercompensated muscle glycogen in trained subjects after carbohydrate loading

• Published in: Journal of applied physiology (1985) 1997-01, Vol.82 (1), p.342-347
• Main Authors: Goforth, Harold W, Arnall, Jr., David A, Bennett, Brad L, Law, Patricia G
• Format: Article
• Language: English
• Subjects: Adult; Biological and medical sciences; Dietary Carbohydrates - metabolism; Exercise - physiology; Fundamental and applied biological sciences. Psychology; Glycogen - metabolism; Humans; Male; Muscle, Skeletal - metabolism; Space life sciences; Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/jappl.1997.82.1.342

Harold W. Goforth, Jr., David A. Arnall, Brad L. Bennett, and Patricia G. Law Human Performance Department, Naval Health Research Center, San Diego, California 92186-5122 Received 6 March 1996; accepted in final form 4 September 1996. Goforth, Jr., Harold W., David A. Arnall, Brad L. Bennett, and Patricia G. Law. Persistence of supercompensated muscle glycogen in trained subjects after carbohydrate loading. J. Appl. Physiol. 82(1): 342-347, 1997. Several carbohydrate (CHO)-loading protocols have been used to achieve muscle glycogen supercompensation and prolong endurance performance. This study assessed the persistence of muscle glycogen supercompensation over the 3 days after the supercompensation protocol. Trained male athletes completed a 6-day CHO-loading protocol that included cycle ergometer exercise and dietary manipulations. The 3-day depletion phase began with 115 min of cycling at 75% peak oxygen uptake followed by 3 × 60-s sprints and included the subjects consuming a low-CHO/high-protein/high-fat (10:41:49%) diet. Subjects cycled 40 min at the same intensity for the next 2 days. During the 3-day repletion phase, subjects rested and consumed a high-CHO/low-protein/low-fat (85:08:07%) diet, including a glucose-polymer beverage. A 3-day postloading phase followed, which involved a moderately high CHO diet (60%) and no exercise. Glycogen values for vastus lateralis biopsies at baseline and postloading days 1-3 were 408 ± 168 (SD), 729 ± 222, 648 ± 186, and 714 ± 196 mmol/kg dry wt, respectively. The CHO-loading protocol increased muscle glycogen by 1.79 times baseline, and muscle glycogen remained near this level during the 3-day postloading period. Results indicate that supercompensated muscle glycogen levels can be maintained for at least 3 days in a resting athlete when a moderate-CHO diet is consumed. supercompensation; glucose polymers; humans