{"doi":"10.3389/fphys.2024.1358942","title":"The oxygen uptake efficiency slope does not accurately predict V˙O2peak of children – the Arkansas Active Kids study","abstract":"Background Cardiorespiratory fitness (CRF) is a vital indicator of health. However, accurately measuring peak oxygen consumption ( <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m332\"><mml:mrow><mml:mover accent=\"true\"><mml:mi mathvariant=\"normal\">V</mml:mi><mml:mo>˙</mml:mo></mml:mover></mml:mrow></mml:math> O 2peak ) to determine CRF in children can be challenging. The oxygen uptake efficiency slope (OUES) has been proposed as an alternative metric for predicting <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m3\"><mml:mrow><mml:mover accent=\"true\"><mml:mi mathvariant=\"normal\">V</mml:mi><mml:mo>˙</mml:mo></mml:mover></mml:mrow></mml:math> O 2peak in children, but its accuracy and agreement with measured <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m4\"><mml:mrow><mml:mover accent=\"true\"><mml:mi mathvariant=\"normal\">V</mml:mi><mml:mo>˙</mml:mo></mml:mover></mml:mrow></mml:math> O 2peak remain unclear. Methods A post hoc analysis was conducted in 94 children (ages 7–10 years) who completed an incremental cycle ergometer test to measure <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m5\"><mml:mrow><mml:mover accent=\"true\"><mml:mi mathvariant=\"normal\">V</mml:mi><mml:mo>˙</mml:mo></mml:mover></mml:mrow></mml:math> O 2peak . Body composition (Dual-energy X-ray absorptiometry) was measured, and fat mass index (FMI, kg/m 2 ) and fat-free mass index (FFMI, kg/m 2 ) were calculated. OUES was determined using all respiratory data (OUES 100% ) collected during the cycle ergometer test and using data only up to 60% of heart rate reserve (OUES 60%HRR ). Regression equations to predict <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m6\"><mml:mrow><mml:mover accent=\"true\"><mml:mi mathvariant=\"normal\">V</mml:mi><mml:mo>˙</mml:mo></mml:mover></mml:mrow></mml:math> O 2peak (Pred- <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m7\"><mml:mrow><mml:mover accent=\"true\"><mml:mi mathvariant=\"normal\">V</mml:mi><mml:mo>˙</mml:mo></mml:mover></mml:mrow></mml:math> O 2peak ) were derived from simple and multiple linear regression analysis. Bland-Altman analysis assessed the level of agreement between Pred- <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m8\"><mml:mrow><mml:mover accent=\"true\"><mml:mi mathvariant=\"normal\">V</mml:mi><mml:mo>˙</mml:mo></mml:mover></mml:mrow></mml:math> O 2peak and measured <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m9\"><mml:mrow><mml:mover accent=\"true\"><mml:mi mathvariant=\"normal\">V</mml:mi><mml:mo>˙</mml:mo></mml:mover></mml:mrow></mml:math> O 2peak . Results OUES 60%HRR (β = 0.46, p &amp;lt; 0.0001), age (β = 56.0, p = 0.0004), White race (β = 173.3, p &amp;lt; 0.0003), FFMI (β = 0.98.6, p &amp;lt; 0.000), and FMI (β = −0.40.8, p &amp;lt; 0.000) were retained in the final model. The difference between measured <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m10\"><mml:mrow><mml:mover accent=\"true\"><mml:mi mathvariant=\"normal\">V</mml:mi><mml:mo>˙</mml:mo></mml:mover></mml:mrow></mml:math> O 2peak and Pred- <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m11\"><mml:mrow><mml:mover accent=\"true\"><mml:mi mathvariant=\"normal\">V</mml:mi><mml:mo>˙</mml:mo></mml:mover></mml:mrow></mml:math> O 2peak was not different from zero ( p = 0.999). There was a positive association between the difference of measured <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m12\"><mml:mrow><mml:mover accent=\"true\"><mml:mi mathvariant=\"normal\">V</mml:mi><mml:mo>˙</mml:mo></mml:mover></mml:mrow></mml:math> O 2peak and Pred- <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m13\"><mml:mrow><mml:mover accent=\"true\"><mml:mi mathvariant=\"normal\">V</mml:mi><mml:mo>˙</mml:mo></mml:mover></mml:mrow></mml:math> O 2peak and the average of the two methods (β = 0.79, p = 0.0028). Conclusion There was no mean bias between measured <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m14\"><mml:mrow><m","journal":"Frontiers in Physiology","year":2024,"id":462769,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":1,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9581,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2024-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":266235,"name":"Elisabet Børsheim","orcid":"0000-0002-7842-0625","position":1,"is_corresponding":false},{"id":496398,"name":"Judith Weber","orcid":null,"position":2,"is_corresponding":false},{"id":376350,"name":"Eva C. 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