title: Respiratory muscle function during a six-week period of normocapnic hyperpnoea training.
abstract: Respiratory muscle endurance training (normocapnic hyperpnoea, RMET) improves maximal volitional ventilation (MVV) and respiratory muscle endurance while volitionally-assessed respiratory muscle strength remains unchanged (prior-to-post comparison). What remains unclear is how respiratory muscle function changes/adapts during a defined period of RMET in highly-trained subjects. This study assessed respiratory muscle function during a six-week period of RMET in 13 highly-trained, healthy subjects. Weekly-assessed twitch mouth pressure (prior/post 2.20 ± 0.41 kPa vs. 2.43 ± 0.61 kPa; p=0.14); twitch transdiaphragmatic pressure (prior/post 3.04 ± 0.58 kPa vs. 3.13 ± 0.48 kPa; p=0.58) and maximal inspiratory pressure (prior/post 12.6 ± 3.6 kPa vs. 13.9 ± 3.8 kPa; p=0.06) did not increase. MVV (prior/post 175 ± 18 l/min vs. 207 ± 30 l/min; p=0.001), sniff nasal pressure (prior/post 11.8 ± 2.8 kPa vs. 14.0 ± 2.9 kPa; p=0.003) and maximal expiratory pressure (prior/post 16.9 ± 5.8 kPa vs. 20.9 ± 4.9 kPa; p=0.006) each increased. In conclusion, non-volitionally assessed diaphragmatic strength does not increase during six weeks of RMET in highly-trained subjects, while expiratory muscle strength and MVV rose. Future studies should clarify if these findings apply when assessed during respiratory muscle strength rather than endurance training.
authors.affiliation: Department of Pneumology, University Hospital Freiburg, Killianstrasse 5, D-79106, Freiburg, Germany.
authors.forename: David Johannes
authors.initials: DJ
authors.lastname: Walker
authors.forename: Thomas
authors.initials: T
authors.lastname: Ertl
authors.forename: Stephan
authors.initials: S
authors.lastname: Walterspacher
authors.forename: Daniel
authors.initials: D
authors.lastname: Schlager
authors.forename: Kai
authors.initials: K
authors.lastname: Roecker
authors.forename: Wolfram
authors.initials: W
authors.lastname: Windisch
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Kabitz
mesh_terms: D000328:Adult; D001945:Breathing Exercises; D004311:Double-Blind Method; D006801:Humans; D006985:Hyperventilation; D008280:Magnetics; D008297:Male; D009055:Mouth / Q000294:innervation; D010791:Phrenic Nerve / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D010991:Plethysmography; D012119:Respiration; D012129:Respiratory Function Tests; D012132:Respiratory Muscles / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult
keywords: Diaphragm; Ergospirometry; Respiratory muscle endurance training; Spirotiger; Twitch transdiaphragmatic pressure