title: Glucocorticoids improve high-intensity exercise performance in humans.
abstract: OBJECTIVE
  It was investigated whether oral dexamethasone (DEX) administration improves exercise performance by reducing the initial rate of muscle fatigue development during dynamic exercise.
  
  
  METHODS
  Using a double-blinded placebo controlled randomized crossover design, subjects ingested either 2 × 2 mg of DEX or placebo for five consecutive days. Muscle function was investigated using one-legged kicking exercise and whole body performance was evaluated using a 20-m shuttle run and a 30-m sprint test.
  
  
  RESULTS
  One-legged dynamic knee-extensor exercise time to exhaustion was 29 ± 35% (mean ± SD) longer (P < 0.05) in DEX compared to Placebo. Likewise, total running distance in the shuttle run test was 19 ± 23% longer (P < 0.05), whereas 30-m sprint performance was unaltered. During the initial 75 s of dynamic leg extensions, peak force and rate of force development determined from an electrically evoked twitch declined in a similar way in DEX and placebo. Similarly, the EMG root mean square was similar with DEX and placebo treatment.
  
  
  CONCLUSIONS
  Short-term dexamethasone administration increases high-intensity one-legged kicking time to exhaustion and 20-m shuttle run performance, although sprint ability and the initial loss of muscular force generating capacity are similar after DEX and placebo.
authors: Department of Health Sciences, University of Jaén, Jaén, Spain.
authors: Rafael A
authors: RA
authors: Casuso
authors: Lars
authors: L
authors: Melskens
authors: Thomas
authors: T
authors: Bruhn
authors: Niels H
authors: NH
authors: Secher
authors: Nikolai Baastrup
authors: NB
authors: Nordsborg
mesh_terms: D000328:Adult; D054874:Athletic Performance; D018592:Cross-Over Studies; D003907:Dexamethasone / Q000008:administration & dosage / Q000494:pharmacology*; D004311:Double-Blind Method; D015444:Exercise; D017079:Exercise Tolerance / Q000187:drug effects*; D005938:Glucocorticoids / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D007866:Leg / Q000502:physiology; D008297:Male; D009119:Muscle Contraction; D018763:Muscle Fatigue / Q000187:drug effects; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology
chemical_list: D005938:Glucocorticoids; D003907:Dexamethasone