Skip to Main content Skip to Navigation
Journal articles

Putative protective effect of inspiratory threshold loading against exercise-induced supraspinal diaphragm fatigue

Abstract : The present investigation was intended to assess the consequences of an inspiratory load on the diaphragm central component of fatigue during exercise. We recorded the motor potential evoked (MEP) by transcranial magnetic stimulation of the motor cortex in 10 subjects. The diaphragm and rectus femoris were studied before and 10, 20, and 40 min after two 16-min cycling exercise (E) trials requiring 55% of maximal oxygen uptake: 1) one with an inspiratory threshold load (E + ITL), corresponding to 10% of maximal inspiratory pressure; and 2) the other without the load (E). Dyspnea, heart rate, electromyographic activity of the sternocleidomastoid, and diaphragm work were significantly higher in E + ITL than in E. Neither trial affected the response to phrenic magnetic stimulation, which was performed 15 and 25 min postexercise, or the maximal inspiratory pressure (116 and 120 cm H(2)O before E and E + ITL, respectively, and 110 and 114 cm H(2)O at 30 min postexercise). Whereas the amplitude of the diaphragm MEP was unaffected by E + ITL (+2.1 +/- 29.4%), a significant decrease was observed 10 min after E compared with baseline (-37.1 +/- 22.3%) and compared with E + ITL. The MEP amplitude of rectus femoris remained unchanged with E and E + ITL. The recruitment of synergistic agonists during E + ITL may have normalized the major ventilatory stress and reset up the excitability of the diaphragm pathway.
Complete list of metadatas

https://hal.archives-ouvertes.fr/hal-01203652
Contributor : Sophie Antoine-Jonville <>
Submitted on : Monday, March 27, 2017 - 5:04:14 PM
Last modification on : Wednesday, January 29, 2020 - 11:32:02 AM
Long-term archiving on: : Wednesday, June 28, 2017 - 12:16:13 PM

File

Jonville ITL 2004.pdf
Files produced by the author(s)

Licence


Distributed under a Creative Commons Attribution - NonCommercial 4.0 International License

Identifiers

Citation

Sophie Antoine-Jonville, Luce Jutand, Thomas Similowski, André Denjean, Nathalie Delpech. Putative protective effect of inspiratory threshold loading against exercise-induced supraspinal diaphragm fatigue. Journal of Applied Physiology, American Physiological Society, 2005, 98 (3), pp.991-998. ⟨10.1152/japplphysiol.00528.2004⟩. ⟨hal-01203652⟩

Share

Metrics

Record views

222

Files downloads

312