Respiratory Muscle Power and the Slow Component of O2 Uptake

Cross, Troy J.; Winters, Caroline; Sheel, A. William; Sabapathy, Surendran

doi:10.1249/mss.0000000000000306

Cited by 15 publications

(15 citation statements)

References 40 publications

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“…Recently, Oueslati et al [15] showed a significant correlation between the VO 2 SC and the decline in maximal inspiratory and expiratory pressure during a constant-load exercise at 85% of maximal aerobic power. These results corroborate those of Cross et al [16,17] showing that the VO 2 SC is strongly related to respiratory muscle work during a constant-load exercise at a work rate roughly equal to 25% and 60% of the difference between the GET and VO 2peak . Potential limitations of the aforementioned studies include unique exercise intensity being studied and the fact that exercise was not conduct until exhaustion.…”

Section: Despite Decades Of Research the Vo 2 Sc Underpinning Mechansupporting

confidence: 92%

Respiratory and Muscle Oxygenation Responses to Two Constant-Load Exercise Intensities

Oueslati¹,

Girard²,

Ahmaidi³

2018

J Athl Enhanc

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Objective: We investigated the respiratory and vastus lateralis oxygenation responses to exhaustive, constant-load cycling at two exercise intensities. Methods: Eight moderately-trained male randomly cycled to exhaustion at 75% and 85% of maximal work-load (CL75 and CL85, respectively) measured during a maximal incremental test. From continuous recordings of respiratory variables and near-infrared spectroscopy signals of the vastus lateralis muscle, VO 2 slow component (SC) and deoxyhemoglobin (HHb) SC were calculated. Results: At exhaustion, VO 2 (+19 ± 25%), VO 2 SC (+59 ± 24%) and minute ventilation (+14 ± 14%) were significantly higher during CL85 vs. CL75, whereas oxyhemoglobin (-67 ± 22%) and total hemoglobin (-36 ± 3%) responses were lower (all p<0.05). Additionally, VO 2 SC during CL75 and CL85 were strongly correlated (r=0.88, p<0.001). The HHb SC did not differ between CL75 and CL85 (3.10 ± 0.75 vs. 3.44 ± 1.1 A.U, respectively; p=0.60). HHb SC and VO 2 SC during CL85 (r=0.94, p<0.001), but not during CL75 (r=-0.08, p=0.90), were correlated. Finally, HHb SC during CL75 and CL85 were unrelated (r=-0.20, p=0.70). Conclusion: Our results highlight that only the contribution of locomotor muscles to the VO 2 SC magnitude is affected by the exercise intensity and not that of ventilation.

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Section: Despite Decades Of Research the Vo 2 Sc Underpinning Mechansupporting

confidence: 92%

Respiratory and Muscle Oxygenation Responses to Two Constant-Load Exercise Intensities

Oueslati¹,

Girard²,

Ahmaidi³

2018

J Athl Enhanc

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“…; Cross et al. , ) and have demonstrated clinical usefulness by helping guide mechanical ventilation therapy (Talmor et al. ; Plataki and Hubmayr ; Akoumianaki et al.…”

Section: Introductionmentioning

confidence: 99%

“…These parameters include the resistance and compliance of the lungs and chest wall, intrinsic positive end-expiratory pressures, and respiratory muscle work and fatigue. These parameters offer insight into the energetics of respiratory muscle work in healthy and clinical populations (Johnson et al 1992(Johnson et al , 1993(Johnson et al , 1996Prigent et al 2008;Cross et al 2012Cross et al , 2014 and have demonstrated clinical usefulness by helping guide mechanical ventilation therapy (Talmor et al 2008;Plataki and Hubmayr 2011;Akoumianaki et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Response characteristics of esophageal balloon catheters handmade using latex and nonlatex materials

et al. 2015

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The measurement of esophageal pressure allows for the calculation of several important and clinically useful parameters of respiratory mechanics. Esophageal pressure is often measured with balloon-tipped catheters. These catheters may be handmade from natural latex condoms and polyethylene tubing. Given the potential of natural latex to cause allergic reaction, it is important to determine whether esophageal catheter balloons can be fabricated, by hand, using nonlatex condoms as construction materials. To determine the static and dynamic response characteristics of esophageal balloon catheters handmade from latex and nonlatex materials, six esophageal catheter balloons were constructed from each of the following condom materials: natural latex, synthetic polyisoprene, and polyurethane (18 total). Static compliance and working volume range of each balloon catheter was obtained from their pressure-volume characteristics in water. The dynamic response of balloon catheters were measured via a pressure “step” test, from which a third-order underdamped transfer function was modeled. The dynamic ranges of balloon catheters were characterized by the frequencies corresponding to ±5% amplitude- and phase-distortion (fA5% and fφ5%). Balloon catheters handmade from polyurethane condoms displayed the smallest working volume range and lowest static balloon compliance. Despite this lower compliance, fA5% and fφ5% were remarkably similar between all balloon materials. Our findings suggest that polyisoprene condoms are an ideal nonlatex construction material to use when fabricating esophageal catheter balloons by hand.

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“…The raw, uncorrected MEFV curve was obtained from the single effort with the largest VC, and most positive peak expiratory P OES , from the GVC maneuvers performed at ~100% of maximum effort; this raw curve is referred to hereafter as MEFV raw . The TGC-corrected MEFV envelope was obtained by taking the highest FEF observed at a given lung volume across all GVC efforts (Cross et al, 2018;Cross, Winters, Sheel, & Sabapathy, 2014;Guenette et al, 2010;Olafsson & Hyatt, 1969). This "maximal perimeter" MEFV curve is thought to mitigate the issue(s) associated with TGC during forced expirations (Cross et al, 2014(Cross et al, , 2018Guenette et al, 2010;Olafsson & Hyatt, 1969).…”

Section: Graded Vital Capacity Maneuversmentioning

confidence: 99%

Thoracic gas compression during forced expiration is greater in men than women

et al. 2020

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Intrapleural pressure during a forced vital capacity (VC) maneuver is often in excess of that required to generate maximal expiratory airflow. This excess pressure compresses alveolar gas (i.e., thoracic gas compression [TGC]), resulting in underestimated forced expiratory flows (FEFs) at a given lung volume. It is unknown if TGC is influenced by sex; however, because men have larger lungs and stronger respiratory muscles, we hypothesized that men would have greater TGC. We examined TGC across the “effort‐dependent” region of VC in healthy young men (n = 11) and women (n = 12). Subjects performed VC maneuvers at varying efforts while airflow, volume, and esophageal pressure (POES) were measured. Quasistatic expiratory deflation curves were used to obtain lung recoil (PLUNG) and alveolar pressures (i.e., PALV = POES–PLUNG). The raw maximal expiratory flow–volume (MEFVraw) curve was obtained from the “maximum effort” VC maneuver. The TGC‐corrected curve was obtained by constructing a “maximal perimeter” curve from all VC efforts (MEFVcorr). TGC was examined via differences between curves in FEFs (∆FEF), area under the expiratory curves (∆AEX), and estimated compressed gas volume (∆VGC) across the VC range. Men displayed greater total ∆AEX (5.4 ± 2.0 vs. 2.0 ± 1.5 L2·s−1; p < .001). ∆FEF was greater in men at 25% of exhaled volume only (p < .05), whereas ∆VGC was systematically greater in men across the entire VC (main effect; p < .05). PALV was also greater in men throughout forced expiration (p < .01). Taken together, these findings demonstrate that men display more TGC, occurring early in forced expiration, likely due to greater expiratory pressures throughout the forced VC maneuver.

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Respiratory Muscle Power and the Slow Component of O2 Uptake

Abstract: The findings of this investigation support the thesis that the energetic contribution from respiratory muscles to the V˙O2sc amplitude is disproportionately higher during severe- compared with that during heavy-intensity exercise.

Cited by 15 publications

References 40 publications

Respiratory and Muscle Oxygenation Responses to Two Constant-Load Exercise Intensities

Respiratory and Muscle Oxygenation Responses to Two Constant-Load Exercise Intensities

Response characteristics of esophageal balloon catheters handmade using latex and nonlatex materials

Thoracic gas compression during forced expiration is greater in men than women

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