This study examined effects of carbohydrate (CHO), milk-based carbohydrate-protein (CHO-PRO), or placebo (P) beverages on glycogen resynthesis, muscle damage, inflammation, and muscle function following eccentric resistance exercise. Untrained males performed a cycling exercise to reduce muscle glycogen 12 hours prior to performance of 100 eccentric quadriceps contractions at 120% of 1-RM (day 1) and drank CHO (n = 8), CHO-PRO (n = 9; 5 kcal/kg), or P (n = 9) immediately and 2 hours post-exercise. At 3 hours post-eccentric exercise, serum insulin was four times higher for CHO-PRO and CHO than P (p < .05). Serum creatine kinase (CK) increased for all groups in the 6 hours post-eccentric exercise (p < .01), with the increase tending to be lowest for CHO-PRO (p < .08) during this period. Glycogen was low post-exercise (33 ± 3.7 mmol/kg ww), increased 225% at 24 hours, and tripled by 72 hours, with no group differences. The eccentric exercise increased muscle protein breakdown as indicated by urinary 3-methylhistidine and increased IL-6 with no effect of beverage. Quadriceps isokinetic peak torque was depressed similarly for all groups by 24% 24 hours post-exercise and remained 21 % lower at 72 hours (p < .01). In summary, there were no influences of any post-exercise beverage on muscle glycogen replacement, inflammation, or muscle function.
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Janet R. Wojcik, Janet Walberg-Rankin, Lucille L. Smith, and F.C. Gwazdauskas
Harry E. Routledge, Jill J. Leckey, Matt J. Lee, Andrew Garnham, Stuart Graham, Darren Burgess, Louise M. Burke, Robert M. Erskine, Graeme L. Close, and James P. Morton
Invasive team sports such as soccer, 1 , 2 rugby league, 2 and Australian Football (AF) 2 , 3 are characterized by high-intensity (>19.8 km/h) intermittent activity profiles. Given the duration of activity (ie, 80–120 min) and high-intensity intermittent profiles, muscle glycogen is considered
Hilkka Kontro, Marta Kozior, Gráinne Whelehan, Miryam Amigo-Benavent, Catherine Norton, Brian P. Carson, and Phil Jakeman
The relationship between postexercise carbohydrate (CHO) intake and subsequent endurance performance is well established, but equivocal evidence exists of the role of protein in the restoration of whole-body glycogen stores ( Alghannam et al., 2018 ). Several studies have suggested that providing
Devin G. McCarthy and Lawrence L. Spriet
of CHO oxidized at high intensity coming from muscle glycogen. 1 , 2 Although muscle glycogen provides an important energy source for skeletal muscle, stores are limited, and whole-muscle depletion is associated with exercise fatigue. 3 Skeletal muscle glycogen is a complex structure that is stored
Samuel G. Impey, Kelly M. Hammond, Robert Naughton, Carl Langan-Evans, Sam O. Shepherd, Adam P. Sharples, Jessica Cegielski, Kenneth Smith, Stewart Jeromson, David L. Hamilton, Graeme L. Close, and James P. Morton
adopted an experimental design whereby male cyclists completed a nonexhaustive training session in which glycogen remained within an absolute concentration (i.e., pre- and postexercise concentrations of <350 and >100 mmol/kg·dry weight (dw), respectively) considered representative of train-low conditions
Sally P. Waterworth, Connor C. Spencer, Aaron L. Porter, and James P. Morton
In addition to its well-documented role as an energy source, it is now recognized that the glycogen granule exerts regulatory roles in modulating skeletal muscle cell signaling and transcriptional responses to acute exercise sessions ( Bartlett et al., 2015 ; Hearris et al., 2018 ). Accordingly
Laís Monteiro Rodrigues Loureiro, Caio Eduardo Gonçalves Reis, and Teresa Helena Macedo da Costa
& Clarke, 2016 ) exercises. After cessation of endurance exercise, muscle glycogen is typically restored to preexercise concentrations within 24 hr when sufficient amounts of high-glycemic-index carbohydrates (CHOs) (≥1.0 g/kg) are immediately ingested ( Burke et al., 2016 ). However, for athletes involved
Campbell Menzies, Michael Wood, Joel Thomas, Aaron Hengist, Jean-Philippe Walhin, Robbie Jones, Kostas Tsintzas, Javier T. Gonzalez, and James A. Betts
Energy metabolism during moderate- to high-intensity exercise is predominantly supported by carbohydrate oxidation ( Hawley & Leckey, 2015 ). Consequently, finite endogenous stores (i.e., glycogen) are progressively depleted and are implicated in the initiation of fatigue ( Bergström et al., 1967
Isabella Russo, Paul A. Della Gatta, Andrew Garnham, Judi Porter, Louise M. Burke, and Ricardo J.S. Costa
Carbohydrate availability can alter physiological and metabolic activity underpinning recovery outcomes, which includes training adaptations. 1 Muscle glycogen plays a key regulatory role for skeletal-muscle fuel utilization, enzyme activity, cellular signaling events, and gene expression. 2
Andy J. King, Joshua T. Rowe, and Louise M. Burke
CHO availability benefit from an exogenous CHO supply ( Stellingwerff & Cox, 2014 ), with mechanisms including fuel provision once muscle glycogen is depleted ( Coyle et al., 1986 ), spared liver ( Gonzalez et al., 2015 ; Wallis et al., 2006 ) and muscle ( King et al., 2018 ; Tsintzas et al., 1995
