title: Albuterol helps resistance exercise attenuate unloading-induced knee extensor losses.
abstract: BACKGROUND
  While resistance exercise (REX) attenuates knee extensor (KE) mass and strength deficits during short-term unloading, additional treatments concurrently administered with REX are required to reduce the greater losses seen with longer periods of unloading.
  
  
  METHODS
  To determine whether albuterol helps REX attenuate unloading-induced KE losses, two groups of subjects strength trained their left thigh three times per week, and otherwise refrained from ambulatory and weight-bearing activity for 40 d while receiving a capsule dosing treatment (albuterol, placebo) with no crossover. A third group served as unloaded controls (CTRL). On days 0, 20, and 40, the following data were collected from the nonweight-bearing (left) thigh: cross-sectional area (CSA); integrated electromyography (IEMG); and concentric and eccentric KE strength measures. Thigh CSA was estimated using anthropometric methodology. IEMG was used to provide root mean square (RMS) values from submaximal (100 nm) and maximal isometric contractions. Concentric and eccentric strength were measured from eight-repetition unilateral leg press sets.
  
  
  RESULTS
  Repeated-measures mixed-factorial 3 x 3 ANCOVAs with day 0 values as a covariate showed group by time interactions for concentric and eccentric total work (CTW, ETW). Tukey's post hoc test showed REX-albuterol evoked significant (p < 0.05) day 40 CTW and ETW gains vs. within-group day 0 and within-time REX-placebo and CTRL values. By days 20 and 40, CTRL subjects incurred significant decrements.
  
  
  CONCLUSIONS
  Albuterol augmented the effects of REX to increase CTW and ETW. Research identifying possible mechanisms responsible for such changes, as well as the safety of REX-albuterol administration in other models, is warranted.
authors.affiliation: Exercise Physiology Laboratory, University of Nevada, Reno, NV, USA. john-caruso@utulsa.edu
authors.forename: John F
authors.initials: JF
authors.lastname: Caruso
authors.forename: John L
authors.initials: JL
authors.lastname: Hamill
authors.forename: Miki
authors.initials: M
authors.lastname: Yamauchi
authors.forename: Dean R
authors.initials: DR
authors.lastname: Mercado
authors.forename: Tim D
authors.initials: TD
authors.lastname: Cook
authors.forename: Chris P
authors.initials: CP
authors.lastname: Keller
authors.forename: Aaron G
authors.initials: AG
authors.lastname: Montgomery
authors.forename: Jeff
authors.initials: J
authors.lastname: Elias
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000420:Albuterol / Q000494:pharmacology*; D004311:Double-Blind Method; D004576:Electromyography; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007537:Isometric Contraction; D007719:Knee Joint / Q000502:physiology; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects*
chemical_list: D000318:Adrenergic beta-Agonists; D000420:Albuterol