Performance in short-duration sports is highly dependent on muscle glycogen, but the total degradation is only moderate and considering the water-binding property of glycogen, unnecessary storing of glycogen may cause an unfavorable increase in body mass. To investigate this, we determined the effect of manipulating dietary carbohydrates (CHO) on muscle glycogen content, body mass and short-term exercise performance. In a cross-over design twenty-two men completed two maximal cycle tests of either 1-min (n = 10) or 15-min (n = 12) duration with different pre-exercise muscle glycogen levels. Glycogen manipulation was initiated three days prior to the tests by exercise-induced glycogen-depletion followed by ingestion of a moderate (M-CHO) or high (H-CHO) CHO-diet. Subjects were weighed before each test, and muscle glycogen content was determined in biopsies from m. vastus lateralis before and after each test. Pre-exercise muscle glycogen content was lower following M-CHO than H-CHO (367 mmol · kg -1 DW vs. 525 mmol · kg -1 DW, P < 0.00001), accompanied by a 0.7 kg lower body mass (P < 0.00001). No differences were observed in performance between diets in neither the 1-min (P = 0.33) nor the 15-min (P = 0.99) test. In conclusion, pre-exercise muscle glycogen content and body mass was lower after ingesting moderate compared with high amounts of CHO, while short-term exercise performance was unaffected. This demonstrates that adjusting pre-exercise glycogen levels to the requirements of competition may provide an attractive weight management strategy in weight-bearing sports, particularly in athletes with high resting glycogen levels.
|Journal||Scandinavian Journal of Medicine & Science in Sports|
|Publication status||Published - Jul 2023|
Bibliographical noteFunding Information:
We express our gratitude to Dorte Mengers Flindt and Chris Christensen for invaluable technical assistance, and Louise Leonora Udstad Petersen for invaluable help to conduct the experiments. The present study was supported by Team Denmark by means from the Novo Nordisk Foundation to the Danish Elite Endurance Performance Network, The Danish Ministry of Culture (FPK.2020‐0042) and Swedish Olympic Committee.
- diet manipulation
- skeletal muscle
- weight management
- Dietary Carbohydrates
- Cross-Over Studies
- Muscle, Skeletal/physiology