title: Effect of formoterol, a long-acting β2-adrenergic agonist, on muscle strength and power output, metabolism, and fatigue during maximal sprinting in men.
abstract: The aim was to investigate the effect of the long-acting β2-adrenergic agonist formoterol on muscle strength and power output, muscle metabolism, and phosphorylation of CaMKII Thr(287) and FXYD1 during maximal sprinting. In a double-blind crossover study, 13 males [V̇o2 max: 45.0 ± 0.2 (means ± SE) ml·min(-1)·kg(-1)] performed a 30-s cycle ergometer sprint after inhalation of either 54 μg of formoterol (FOR) or placebo (PLA). Before and after the sprint, muscle biopsies were collected from vastus lateralis and maximal voluntary contraction (MVC), and contractile properties of quadriceps were measured. Oxygen uptake was measured during the sprint. During the sprint, peak power, mean power, and end power were 4.6 ± 0.8, 3.9 ± 1.1, and 9.5 ± 3.2% higher (P < 0.05) in FOR than in PLA, respectively. Net rates of glycogenolysis and glycolysis were 45.7 ± 21.0 and 28.5 ± 13.4% higher (P < 0.05) in FOR than in PLA, respectively, and the decrease in ATP content was lower (P < 0.05) in FOR than in PLA (3.7 ± 1.5 vs. 8.0 ± 1.6 mmol/kg dry weight). There was no difference in breakdown of phosphocreatine and oxygen uptake between treatments. Before and after the sprint, MVC and peak twitch force were higher (P < 0.05) in FOR than in PLA. No differences were observed in phosphorylation of CaMKII Thr(287) and FXYD1 between treatments before the sprint, whereas phosphorylation of CaMKII Thr(287) and FXYD1 was greater (P < 0.05) in FOR than in PLA after the sprint. In conclusion, formoterol-induced enhancement in power output during maximal sprinting is associated with increased rates of glycogenolysis and glycolysis that may counteract development of fatigue.
authors.affiliation: Respiratory Research Unit, Bispebjerg University Hospital, Denmark; and Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Kalsen
authors.affiliation: Respiratory Research Unit, Bispebjerg University Hospital, Denmark; and Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Hostrup
authors.affiliation: Respiratory Research Unit, Bispebjerg University Hospital, Denmark; and.
authors.forename: Vibeke
authors.initials: V
authors.lastname: Backer
authors.affiliation: Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Denmark jbangsbo@nexs.ku.dk.
authors.forename: Jens
authors.initials: J
authors.lastname: Bangsbo
mesh_terms: D058672:Adrenergic beta-2 Receptor Antagonists / Q000008:administration & dosage; D000328:Adult; D054874:Athletic Performance / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology; D000068759:Formoterol Fumarate / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D018763:Muscle Fatigue / Q000187:drug effects / Q000502:physiology*; D053580:Muscle Strength / Q000187:drug effects / Q000502:physiology*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology*; D058573:Performance-Enhancing Substances / Q000008:administration & dosage; D010807:Physical Endurance / Q000187:drug effects / Q000502:physiology*; D005082:Physical Exertion / Q000187:drug effects / Q000502:physiology; D012420:Running / Q000502:physiology*
chemical_list: D058672:Adrenergic beta-2 Receptor Antagonists; D058573:Performance-Enhancing Substances; D000068759:Formoterol Fumarate
keywords: fatigue; muscle metabolism; sprint performance; β2-agonist