Ultrasound Does Not Detect Acute Changes in Glycogen in Vastus Lateralis of Man
Routledge, Harry E1; Bradley, Warren J1; Shepherd, Sam O1; Cocks, Matthew1; Erskine, Robert M1,2; Close, Graeme L1; Morton, James P1
Medicine & Science in Sports & Exercise: May 31, 2019 - Volume Publish Ahead of Print - Issue - p
doi: 10.1249/MSS.0000000000002052
Original Investigation: PDF Only
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Purpose To examine the validity of ultrasound (via cloud based software that measures pixilation intensity according to a scale of 0-100) to non-invasively assess muscle glycogen in human skeletal muscle.
Methods In Study 1, 14 professional male rugby league players competed in an 80-minute competitive rugby league game. In Study 2 (in a randomized repeated measures design), 16 recreationally active males completed an exhaustive cycling protocol to deplete muscle glycogen followed by 36 hours of HIGH or LOW carbohydrate intake (8 v 3 g.kg-1 body mass). In both studies, muscle biopsies and ultrasound scans were obtained from the vastus lateralis (at 50% of the muscle length) before and after match play in Study 1 and at 36 h after glycogen depletion in Study 2.
Results Despite match play reducing (P< 0.01) muscle glycogen concentration (Pre-game: 443 ± 65; Post-game: 271 ± 94 mmol.kg-1 dw, respectively) in Study 1, there were no significant changes (P=0.4) in ultrasound scores (Pre-game: 47 ± 6, Post-game: 49 ± 7). In Study 2, muscle glycogen concentration was significantly different (P < 0.01) between HIGH (531 ± 129 mmol.kg-1 dw) and LOW (252 ± 64 mmol.kg-1 dw) yet there was no difference (P = 0.9) in corresponding ultrasound scores (HIGH: 56 ± 7, LOW: 54 ± 6). In both studies, no significant correlations (P>0.05) were present between changes in muscle glycogen concentration and changes in ultrasound scores.
Conclusion Data demonstrate that ultrasound (as based on measures of pixilation intensity) is not valid to measure muscle glycogen status within the physiological range (i.e. 200-500 mmol.kg-1 dw) that is applicable to exercise-induced muscle glycogen utilization and post-exercise muscle glycogen re-synthesis.
© 2019 American College of Sports Medicine
Routledge, Harry E1; Bradley, Warren J1; Shepherd, Sam O1; Cocks, Matthew1; Erskine, Robert M1,2; Close, Graeme L1; Morton, James P1
Medicine & Science in Sports & Exercise: May 31, 2019 - Volume Publish Ahead of Print - Issue - p
doi: 10.1249/MSS.0000000000002052
Original Investigation: PDF Only
BUY
PAP
Abstract
Author Information
Article Metrics
Purpose To examine the validity of ultrasound (via cloud based software that measures pixilation intensity according to a scale of 0-100) to non-invasively assess muscle glycogen in human skeletal muscle.
Methods In Study 1, 14 professional male rugby league players competed in an 80-minute competitive rugby league game. In Study 2 (in a randomized repeated measures design), 16 recreationally active males completed an exhaustive cycling protocol to deplete muscle glycogen followed by 36 hours of HIGH or LOW carbohydrate intake (8 v 3 g.kg-1 body mass). In both studies, muscle biopsies and ultrasound scans were obtained from the vastus lateralis (at 50% of the muscle length) before and after match play in Study 1 and at 36 h after glycogen depletion in Study 2.
Results Despite match play reducing (P< 0.01) muscle glycogen concentration (Pre-game: 443 ± 65; Post-game: 271 ± 94 mmol.kg-1 dw, respectively) in Study 1, there were no significant changes (P=0.4) in ultrasound scores (Pre-game: 47 ± 6, Post-game: 49 ± 7). In Study 2, muscle glycogen concentration was significantly different (P < 0.01) between HIGH (531 ± 129 mmol.kg-1 dw) and LOW (252 ± 64 mmol.kg-1 dw) yet there was no difference (P = 0.9) in corresponding ultrasound scores (HIGH: 56 ± 7, LOW: 54 ± 6). In both studies, no significant correlations (P>0.05) were present between changes in muscle glycogen concentration and changes in ultrasound scores.
Conclusion Data demonstrate that ultrasound (as based on measures of pixilation intensity) is not valid to measure muscle glycogen status within the physiological range (i.e. 200-500 mmol.kg-1 dw) that is applicable to exercise-induced muscle glycogen utilization and post-exercise muscle glycogen re-synthesis.
© 2019 American College of Sports Medicine
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