Effects of exercise mode on muscle glycogen restorage during repeated days of exercise
Pascoe, David D., Costill, David L., Robergs, Robert A., Davis, Jacqueline, Fink, William J., & Pearson, David R. (1990) Effects of exercise mode on muscle glycogen restorage during repeated days of exercise. Medicine and Science in Sports and Exercise, 22(5), pp. 593-598.
The purpose of this study was to examine differences in muscle glycogen storage during three successive days of running or cycling. In a crossover design, seven male subjects performed two 3-d trials of either running (trial R) or cycling (trial C) for 60 min at 75% VO2max. Biopsy samples were obtained before and after each day’s exercise from the gastrocnemius (trial R) or vastus lateralis (trial C) muscle. Diets in the 2 d preceding and during each trial contained 5 g carbohydrate · kg−1·d−1 and 14,475 ± 402 kJ·d−1. Mean pre-exercise glycogen content (mmol-kg−1 wet wt.) was significantly reduced in both trials on day 3 (103.4 ± 6.0) when compared to day 1 and day 2 (119.9 ± 6.8 and 116.4 ± 5.7, respectively). Day 1 glycogen reduction was significantly greater in trial C (P < 0.03), and glycogen restorage was greater (P < 0.02) only in trial C between the 1st and 2nd d. On day 3, spectro-photometric analysis of PAS strains showed that pre-exercise glycogen content in either muscle group was significantly (P < 0.01) less in Type I as compared to Type II fibers. This difference in fiber glycogen storage did not appear to be attributable to muscle damage as negligible leukocyte infiltration and low blood CK levels were obtained. No difference between modes were observed for CK values throughout the trials. These data suggest that the depressed glycogen storage before the 3rd d of exercise was due to the moderate carbohydrate intake.
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|Item Type:||Journal Article|
|Keywords:||carbohydrate, adult; article; clinical trial; controlled study; cycling; diet; exercise; glycogen muscle level; human; human experiment; male; muscle biopsy; normal human; priority journal; running, Adult; Bicycling; Creatine Kinase; Dietary Carbohydrates; Exercise; Glycogen; Human; Lactates; Male; Muscles; Physical Endurance; Pilot Projects; Running; Support, Non-U.S. Gov't|
|Divisions:||Current > QUT Faculties and Divisions > Faculty of Health
Current > Schools > School of Exercise & Nutrition Sciences
|Deposited On:||18 Jul 2016 23:55|
|Last Modified:||18 Jul 2016 23:55|
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