Reproducibility of Open Circuit Acetylene-Derived Cardiac Output at Moderate, Heavy, and Severe Exercise Intensities
Notice bibliographique
Résumé
The objective of this test-retest study was to determine the reproducibility of open-circuit acetylene uptake-derived measures of [Formula: see text] during repeated measures of cycling exercise within the moderate, heavy, and severe intensity domains. Seventeen healthy participants (mean±SD, 53±15 [range: 22-75] years; 9 females) completed a maximal incremental cycling exercise protocol (Visit 1) and two step-incremental protocols (Visits 2 and 3) over three days. The step-incremental protocol involved 10-min of cycling within the moderate-intensity domain (MOD; 85% of gas exchange threshold (GET)), then 10-min within the heavy-intensity domain (HVY; 70% between GET and respiratory compensation point (RCP)) and up to 10 min within the severe-intensity domain (SVR; 115%RCP) or until task disengagement. During MOD and HVY, open-circuit inspiration of 0.7%C 2 H 2 , 7%He, and 21%O 2 in nitrogen was applied over 10-12 breaths at 2.5, 5.0, and 7.5 min. During the SVR stage, open-circuit breathing occurred at 2.0 min and during the final min of exercise as indicated by the participant. The integrated uptake versus end-tidal change in acetylene approach was used to calculate [Formula: see text]. A two-way (trial x day) repeated measures analysis of variance and intraclass correlation coefficient (ICC) assessed within- and between-day reproducibility at each intensity. Average power output for MOD, HVY, and SVR were 98±54, 138±72, and 174±90 W, eliciting steady-state [Formula: see text]O 2 of 1.58±0.72 and 2.05±0.89 and peak [Formula: see text]O 2 of 2.31±0.97 L·min -1 . For all intensities, there were no interactions or main effects. For MOD on Day 1, [Formula: see text] were 12.0±4.6, 12.1±5.5, and 11.5±4.5 L·min -1 , at 2.5, 5.0 and 7.5 min, respectively (ICC=0.98) and on Day 2 were 11.8±4.2, 11.2±3.7, and 11.4±3.8 L·min -1 (ICC=0.990). For HVY on Day 1, [Formula: see text] were 14.1±5.4, 13.8±5.0, and 13.2±4.2 L·min -1 (ICC=0.995) and on Day 2 were 14.0±4.5, 13.6±5.0, and 13.0±3.8 L·min -1 (ICC=0.99). For SVR on Day 1, [Formula: see text] were 15.3±4.8 and 15.1±5.0 L·min -1 at 2.0 and end-exercise, respectively, and on Day 2 these values were 15.0±5.0 and 15.4±6.1 L·min -1 . Open-circuit acetylene derived measures of [Formula: see text] exhibited excellent test-retest reproducibility both within-intensities and between-days and this was consistent within all three exercise-intensity domains. Daniel A. Keir was supported by a NSERC Discovery Grant (RGPIN-2021-03980) and by the Canadian Foundation for Innovation John Evans Leadership Fund (Project: 42544). This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,002 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,001 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».