Persistence of supercompensated muscle glycogen in trained subjects
after carbohydrate loading.
Goforth, Harold W., David A. Arnall, Brad L. Bennett, Patricia G. Law.
Physiological Performance and Operational Medicine Department,
Naval Health Research Center, San Diego, California 92186-5122
APStracts 3:0411A, 1996.
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 three days following 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 V x O2 followed by 3 x 60 sec sprints, and
included 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 post-loading phase followed, which involved
a moderate-CHO diet (60%) and no exercise. Glycogen values (x- +/-
SD) for vastus lateralis biopsies at baseline and post-loading days
1-3 were 408 +/- 168, 729 +/- 222, 648 +/- 186, and 714 +/- 196 mmol
x kg-1 DW, respectively. The CHO-loading protocol increased muscle
glycogen by 1.79 times baseline and muscle glycogen remained near
this level during the 3-day post-loading period. Results indicate
that supercompensated muscle glycogen levels can be maintained for at
least three days in a resting athlete when consuming a moderate
carbohydrate diet.
Received 6 March 1996; accepted in final form 4 September 1996.
APS Manuscript Number A223-6.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 19 September 1996