TY - JOUR
T1 - Lowered muscle glycogen reduces body mass with no effect on short-term exercise performance in men
AU - Schytz, Camilla Tvede
AU - Ørtenblad, Niels
AU - Birkholm, Thor Andersen
AU - Plomgaard, Peter
AU - Nybo, Lars
AU - Kolnes, Kristoffer Jensen
AU - Andersen, Ole Emil
AU - Lundby, Carsten
AU - Nielsen, Joachim
AU - Gejl, Kasper Degn
PY - 2023/7
Y1 - 2023/7
N2 - 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 randomized and counterbalanced 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 were 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.
AB - 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 randomized and counterbalanced 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 were 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.
KW - diet manipulation
KW - fatigue
KW - skeletal muscle
KW - taper
KW - weight management
UR - http://www.scopus.com/inward/record.url?scp=85150953008&partnerID=8YFLogxK
U2 - 10.1111/sms.14354
DO - 10.1111/sms.14354
M3 - Journal article
C2 - 36932633
AN - SCOPUS:85150953008
SN - 0905-7188
VL - 33
SP - 1054
EP - 1071
JO - Scandinavian Journal of Medicine and Science in Sports
JF - Scandinavian Journal of Medicine and Science in Sports
IS - 7
ER -