title: Comparison of carbohydrate and milk-based beverages on muscle damage and glycogen following exercise.
abstract: 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.
authors.affiliation: Department of Human Nutrition, Foods, and Exercise at Virginia Polytechnic Institute and State University, Blacksburg 24061, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Wojcik
authors.forename: J
authors.initials: J
authors.lastname: Walber-Rankin
authors.forename: L L
authors.initials: LL
authors.lastname: Smith
authors.forename: F C
authors.initials: FC
authors.lastname: Gwazdauskas
mesh_terms: D000328:Adult; D000818:Animals; D001628:Beverages; D003402:Creatine Kinase / Q000097:blood; D016207:Cytokines / Q000097:blood; D004040:Dietary Carbohydrates / Q000008:administration & dosage* / Q000378:metabolism; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D006003:Glycogen / Q000096:biosynthesis* / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000097:blood; D007700:Kinetics; D008297:Male; D008762:Methylhistidines / Q000652:urine; D008892:Milk; D018482:Muscle, Skeletal / Q000293:injuries / Q000378:metabolism* / Q000473:pathology
chemical_list: D016207:Cytokines; D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D007328:Insulin; D008762:Methylhistidines; D006003:Glycogen; D003402:Creatine Kinase; C028118:3-methylhistidine