PLoS ONE (Jan 2022)

Non-invasive assessment of fatigue and recovery of inspiratory rib cage muscles during endurance test in healthy individuals.

  • Thiago Bezerra Wanderley E Lima,
  • Antonio Sarmento,
  • Rayane Grayce da Silva Vieira,
  • Esmívany Lhara de Freitas Castro,
  • Francesca Pennati,
  • Andrea Aliverti,
  • Vanessa Regiane Resqueti,
  • Guilherme Augusto de Freitas Fregonezi

DOI
https://doi.org/10.1371/journal.pone.0277131
Journal volume & issue
Vol. 17, no. 12
p. e0277131

Abstract

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IntroductionFatigue is defined as loss of capacity to develop muscle force and/or velocity that is reversible at rest. We assessed non-invasively the fatigue and recovery of inspiratory rib cage muscles during two respiratory endurance tests in healthy individuals.MethodsThe sniff nasal inspiratory pressure (SNIP) was assessed before and after two respiratory endurance tests: normocapnic hyperpnea (NH) and inspiratory pressure threshold loading (IPTL). Contractile (maximum rate of pressure development and time to peak pressure) and relaxation parameters (maximum relaxation rate [MRR], time constant of pressure decay [τ], and half relaxation time) obtained from sniff curves and shortening velocity and mechanical power estimated using optoelectronic plethysmography were analyzed during SNIP maneuvers. Respiratory muscle activity (electromyography) and tissue oxygenation (near-infrared spectroscopy-NIRS) were obtained during endurance tests and SNIP maneuvers. Fatigue development of inspiratory rib cage muscles was assessed according to the slope of decay of median frequency.ResultsPeak pressure during SNIP decreased after both protocols (p ConclusionFatigue development behaved differently between protocols and relaxation properties (MRR and τ), shortening velocity, and mechanical power changed only in the IPTL.