Electrical activity and fatigue of respiratory and locomotor muscles in obstructive respiratory diseases during field walking test

PLoS One. 2022 Apr 1;17(4):e0266365. doi: 10.1371/journal.pone.0266365. eCollection 2022.

Abstract

Introduction: In subjects with obstructive respiratory diseases the increased work of breathing during exercise can trigger greater recruitment and fatigue of respiratory muscles. Associated with these changes, lower limb muscle dysfunctions, further contribute to exercise limitations. We aimed to assess electrical activity and fatigue of two respiratory and one locomotor muscle during Incremental Shuttle Walking Test (ISWT) in individuals with obstructive respiratory diseases and compare with healthy.

Methods: This is a case-control study. Seventeen individuals with asthma (asthma group) and fifteen with chronic obstructive pulmonary disease (COPD group) were matched with healthy individuals (asthma and COPD control groups). Surface electromyographic (sEMG) activity of sternocleidomastoid (SCM), scalene (ESC), and rectus femoris (RF) were recorded during ISWT. sEMG activity was analyzed in time and frequency domains at baseline and during the test (33%, 66%, and 100% of ISWT total time) to obtain, respectively, signal amplitude and power spectrum density (EMG median frequency [MF], high- and low-frequency bands, and high/low [H/L] ratio).

Results: Asthma group walked a shorter distance than controls (p = 0.0007). sEMG amplitudes of SCM, ESC, and RF of asthma and COPD groups were higher at 33% and 66% of ISWT compared with controls groups (all p<0.05). SCM and ESC of COPD group remained higher until 100% of the test. MF of ESC and RF decreased in asthma group (p = 0.016 and p < 0.0001, respectively) versus controls, whereas MF of SCM (p < 0.0001) decreased in COPD group compared with controls. H/L ratio of RF decreased (p = 0.002) in COPD group versus controls.

Conclusion: Reduced performance is accompanied by increased electromyographic activity of SCM and ESC and activation of RF in individuals with obstructive respiratory diseases during ISWT. These are susceptible to be more pronounced respiratory and peripheral muscle fatigue than healthy subjects during exercise.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Asthma*
  • Case-Control Studies
  • Exercise Test
  • Humans
  • Pulmonary Disease, Chronic Obstructive*
  • Respiration Disorders*
  • Respiratory Muscles
  • Walking / physiology

Grants and funding

This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001. G.A.F.F received a grant from CNPq number 312876/2018-1 and V.R.R received a grant from CNPq number 315580/2018-6. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.