title: Respiratory muscle training extends exercise tolerance without concomitant change to peak oxygen uptake: physiological, performance and perceptual responses derived from the same incremental exercise test.
abstract: OBJECTIVE
  There is conjecture over the efficacy of respiratory muscle training (RMT). The aim of this study was to establish whether or not exercise tolerance, physical performance and effort perceptions are influenced by RMT.
  
  
  METHODS
  Thirty-six healthy males (age 24 ± 4) agreed to participate (experimental group (EXP) n = 18, control (CON) n = 18). RMT was performed using an inspiratory pressure-threshold training device at either 55% (EXP) or 10% (CON) of maximal inspiratory effort. Measurements of spirometry and maximal static inspiratory mouth pressure were taken before and after 4 weeks of RMT in addition to an incremental test to volitional exhaustion for the determination of: (i) V˙O(2) peak; (ii) maximal velocity at volitional exhaustion (vV˙O(2) peak)); (iii) time to volitional exhaustion; and (iv) effort perceptions.
  
  
  RESULTS
  There were no differences in spirometry, but mean maximal static inspiratory mouth pressure increased significantly in EXP (P < 0.01). V˙O(2) peak was unchanged following the 4-week intervention for both EXP and CON, although the proportion of EXP attaining the criteria for a V˙O(2) plateau significantly increased (P < 0.05). Both time to volitional exhaustion (P < 0.05) and vV˙O(2) peak were significantly improved for EXP (P < 0.05), while effort perceptions were reduced (P < 0.05).
  
  
  CONCLUSIONS
  EXP tolerated higher running velocities during incremental exercise and demonstrated a significant flattening (plateau) of V˙O(2) after training. This suggests that RMT may promote an improved performance outcome vV˙O(2) peak probably as a result of blunted afferent sensations reducing the perceived discomfort of exercise at high ventilatory loads.
authors.affiliation: Institute of Sport and Exercise Science, James Cook University, Cairns, Queensland, Australia. andrew.edwards@jcu.edu.au
authors.forename: A M
authors.initials: AM
authors.lastname: Edwards
mesh_terms: D000328:Adult; D001945:Breathing Exercises / Q000379:methods*; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D010465:Perception / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology; D012132:Respiratory Muscles / Q000502:physiology; D013147:Spirometry; D013647:Task Performance and Analysis; D013997:Time Factors
keywords: inspiratory muscle; oxygen uptake plateau; respiratory muscle; training; velocity at peak oxygen uptake