title: Blunted Myoglobin and Quadriceps Soreness After Electrical Stimulation During the Luteal Phase or Oral Contraception.
abstract: OBJECTIVE
  Acute muscle damage after exercise triggers subsequent regeneration, leading to hypertrophy and increased strength after repeated exercise. It has been debated whether acute exercise-induced muscle damage is altered under various premenopausal estrogen conditions. Acute contraction-induced muscle damage was compared during exogenous (oral contraceptive, OC), endogenous (luteal phase, HI), or low (menses, LO) estrogen in healthy young women aged 21 to 30 years old.
  
  
  METHODS
  Women (OC, n = 9; HI, n = 9; LO, n = 8; total N = 26) performed 1 neuromuscular electrical stimulation (NMES) bout. Soreness, measured via visual analog scale and the Likert Scale of Muscle Soreness for Lower Limb (LSMSLL), quadriceps strength, and plasma myoglobin (Mb), interleukin (IL)-6, IL-8, and granulocyte-colony stimulating factor were measured before and after NMES.
  
  
  RESULTS
  NMES performance was similar across groups. Meaningful within-group increases in Mb (effect size [ES] = 1.12) and IL-8 (ES = 0.38) occurred in LO; ES for HI and OC were trivial. ES of the between-group difference in change was moderate for Mb (LO vs. HI = 1.15) and IL-8 (LO vs. HI = 0.86; LO vs. OC = 0.73). 17-β estradiol correlated moderately and negatively with Mb relative change (r = -.52, p < .05). LO had ~5% greater strength loss than OC and HI. The mean change score for the LSMSLL 2 days post-NMES was clinically greater in LO than OC or HI.
  
  
  CONCLUSIONS
  Acute NMES-induced indicators of muscle fiber damage and qualitative muscle soreness may be attenuated during the luteal phase or active OC pill consumption compared with the menstrual phase.
authors.affiliation: a University of Southern California.
authors.forename: Lindsey J
authors.initials: LJ
authors.lastname: Anderson
authors.affiliation: a University of Southern California.
authors.forename: Lucinda L
authors.initials: LL
authors.lastname: Baker
authors.affiliation: a University of Southern California.
authors.forename: E Todd
authors.initials: ET
authors.lastname: Schroeder
mesh_terms: D000328:Adult; D001823:Body Composition / Q000502:physiology; D003278:Contraceptives, Oral, Hormonal / Q000008:administration & dosage*; D004558:Electric Stimulation; D004958:Estradiol / Q000097:blood*; D015444:Exercise / Q000502:physiology*; D005260:Female; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000097:blood; D006801:Humans; D015850:Interleukin-6 / Q000097:blood; D016209:Interleukin-8 / Q000097:blood; D007537:Isometric Contraction / Q000502:physiology; D008183:Luteal Phase / Q000502:physiology*; D063806:Myalgia / Q000503:physiopathology*; D009211:Myoglobin / Q000097:blood*; D055815:Young Adult
chemical_list: C508606:CXCL8 protein, human; D003278:Contraceptives, Oral, Hormonal; C508600:IL6 protein, human; D015850:Interleukin-6; D016209:Interleukin-8; D009211:Myoglobin; D004958:Estradiol; D016178:Granulocyte-Macrophage Colony-Stimulating Factor
keywords: Estrogen; NMES; exercise; muscle damage