title: Time course of glycogen accumulation after eccentric exercise.
abstract: This study examined the time course of glycogen accumulation in skeletal muscle depleted by concentric work and subsequently subjected to eccentric exercise. Eight men exercised to exhaustion on a cycle ergometer [70% of maximal O2 consumption (VO2max)] and were placed on a carbohydrate-restricted diet. Approximately 12 h later they exercised one leg to subjective failure by repeated eccentric action of the knee extensors against a resistance equal to 120% of their one-repetition maximum concentric knee extension force (ECC leg). The contralateral leg was not exercised and served as a control (CON leg). During the 72-h recovery period, subjects consumed 7 g carbohydrate.kg body wt-1.day-1. Moderate soreness was experienced in the ECC leg 24-72 h after eccentric exercise. Muscle biopsies from the vastus lateralis of the ECC and CON legs revealed similar glycogen levels immediately after eccentric exercise (40.2 +/- 5.2 and 47.6 +/- 6.4 mmol/kg wet wt, respectively; P greater than 0.05). There was no difference in the glycogen content of ECC and CON legs after 6 h of recovery (77.7 +/- 7.9 and 85.1 +/- 4.9 mmol/kg wet wt, respectively; P greater than 0.05), but 18 h later, the ECC leg contained 15% less glycogen than the CON leg (90.2 +/- 8.2 vs. 105.8 +/- 8.9 mmol/kg wet wt; P less than 0.05). After 72 h of recovery, this difference had increased to 24% (115.8 +/- 8.0 vs. 153.0 +/- 12.2 mmol/kg wet wt; P less than 0.05). These data confirm that glycogen accumulation is impaired in eccentrically exercised muscle.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Human Performance Laboratory, Ball State University, Muncie, Indiana 47306.
authors.forename: J J
authors.initials: JJ
authors.lastname: Widrick
authors.forename: D L
authors.initials: DL
authors.lastname: Costill
authors.forename: G K
authors.initials: GK
authors.lastname: McConell
authors.forename: D E
authors.initials: DE
authors.lastname: Anderson
authors.forename: D R
authors.initials: DR
authors.lastname: Pearson
authors.forename: J J
authors.initials: JJ
authors.lastname: Zachwieja
mesh_terms: D000328:Adult; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D015444:Exercise / Q000502:physiology*; D006003:Glycogen / Q000378:metabolism*; D006801:Humans; D008297:Male; D009132:Muscles / Q000293:injuries / Q000378:metabolism* / Q000473:pathology; D013997:Time Factors
chemical_list: D004040:Dietary Carbohydrates; D006003:Glycogen