title: Muscle-fiber type and blood oxidative stress after eccentric exercise.
abstract: Acute strength exercise elicits a transient oxidative stress, but the factors underlying the magnitude of this response remain unknown. The purpose of this investigation was to determine whether muscle-fiber type relates to the magnitude of blood oxidative stress after eccentric muscle activity. Eleven college-age men performed 3 sets of 50 eccentric knee-extensions. Blood samples taken pre-, post-, and 24, 48, 72, and 96 hr postexercise were assayed for comparison of muscle damage and oxidative-stress biomarkers including protein carbonyls (PCs). Vastus lateralis muscle biopsies were assayed for relative percentage of slow- and fast-twitch muscle fibers. There was a mixed fiber composition (Type I = 39.6% ± 4.5%, Type IIa = 35.7% ± 3.5%, Type IIx = 24.8% ± 3.8%; p = .366). PCs were elevated 24, 48, and 72 hr (p = .032) postexercise, with a peak response of 126% (p = .012) above baseline, whereas other oxidative-stress biomarkers were unchanged. There are correlations between Type II muscle-fiber type and postexercise PC. Further study is needed to understand the mechanisms responsible for the observed fast-twitch muscle-fiber oxidative-stress relationship.
authors.affiliation: Dept. of Kinesiology, Auburn University, Auburn, AL, USA.
authors.forename: John
authors.initials: J
authors.lastname: Quindry
authors.forename: Lindsey
authors.initials: L
authors.lastname: Miller
authors.forename: Graham
authors.initials: G
authors.lastname: McGinnis
authors.forename: Megan
authors.initials: M
authors.lastname: Irwin
authors.forename: Charles
authors.initials: C
authors.lastname: Dumke
authors.forename: Meir
authors.initials: M
authors.lastname: Magal
authors.forename: N Travis
authors.initials: NT
authors.lastname: Triplett
authors.forename: Jeffrey
authors.initials: J
authors.lastname: McBride
authors.forename: Zea
authors.initials: Z
authors.lastname: Urbiztondo
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007717:Knee / Q000502:physiology; D008297:Male; D009068:Movement / Q000502:physiology; D009119:Muscle Contraction / Q000502:physiology*; D018656:Muscle Fibers, Fast-Twitch / Q000378:metabolism*; D018657:Muscle Fibers, Slow-Twitch / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology*; D050050:Protein Carbonylation; D052097:Quadriceps Muscle / Q000033:anatomy & histology / Q000378:metabolism*; D055815:Young Adult
chemical_list: D015415:Biomarkers