{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,7]],"date-time":"2026-03-07T01:59:38Z","timestamp":1772848778907,"version":"3.50.1"},"reference-count":48,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2024,1,14]],"date-time":"2024-01-14T00:00:00Z","timestamp":1705190400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Portuguese Foundation for Science and Technology to Manoel Rios","award":["FCT202104701BD"],"award-info":[{"award-number":["FCT202104701BD"]}]},{"name":"Portuguese Foundation for Science and Technology to Manoel Rios","award":["UIDB\/04045\/2020"],"award-info":[{"award-number":["UIDB\/04045\/2020"]}]},{"name":"Victor Machado Reis","award":["FCT202104701BD"],"award-info":[{"award-number":["FCT202104701BD"]}]},{"name":"Victor Machado Reis","award":["UIDB\/04045\/2020"],"award-info":[{"award-number":["UIDB\/04045\/2020"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Our purpose was to characterize the oxygen uptake kinetics (VO2), energy systems contributions and total energy expenditure during a CrossFit\u00ae benchmark workout performed in the extreme intensity domain. Fourteen highly trained male CrossFitters, aged 28.3 \u00b1 5.4 years, with height 177.8 \u00b1 9.4 cm, body mass 87.9 \u00b1 10.5 kg and 5.6 \u00b1 1.8 years of training experience, performed the Isabel workout at maximal exertion. Cardiorespiratory variables were measured at baseline, during exercise and the recovery period, with blood lactate and glucose concentrations, including the ratings of perceived exertion, measured pre- and post-workout. The Isabel workout was 117 \u00b1 10 s in duration and the VO2 peak was 47.2 \u00b1 4.7 mL\u00b7kg\u22121\u00b7min\u22121, the primary component amplitude was 42.0 \u00b1 6.0 mL\u00b7kg\u22121\u00b7min\u22121, the time delay was 4.3 \u00b1 2.2 s and the time constant was 14.2 \u00b1 6.0 s. The accumulated VO2 (0.6 \u00b1 0.1 vs. 4.8 \u00b1 1.0 L\u00b7min\u22121) value post-workout increased substantially when compared to baseline. Oxidative phosphorylation (40%), glycolytic (45%) and phosphagen (15%) pathways contributed to the 245 \u00b1 25 kJ total energy expenditure. Despite the short ~2 min duration of the Isabel workout, the oxygen-dependent and oxygen-independent metabolism energy contributions to the total metabolic energy release were similar. The CrossFit\u00ae Isabel requires maximal effort and the pattern of physiological demands identifies this as a highly intensive and effective workout for developing fitness and conditioning for sports.<\/jats:p>","DOI":"10.3390\/s24020513","type":"journal-article","created":{"date-parts":[[2024,1,15]],"date-time":"2024-01-15T07:25:07Z","timestamp":1705303507000},"page":"513","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Assessment of Cardiorespiratory and Metabolic Contributions in an Extreme Intensity CrossFit\u00ae Benchmark Workout"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3574-6692","authenticated-orcid":false,"given":"Manoel","family":"Rios","sequence":"first","affiliation":[{"name":"Center of Research, Education Innovation and Intervention in Sport and Porto Biomechanics Laboratory, Faculty of Sport, University of Porto, 4200-450 Porto, Portugal"}]},{"given":"Klaus Magno","family":"Becker","sequence":"additional","affiliation":[{"name":"Center of Research, Education Innovation and Intervention in Sport and Porto Biomechanics Laboratory, Faculty of Sport, University of Porto, 4200-450 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7829-5222","authenticated-orcid":false,"given":"Filipa","family":"Cardoso","sequence":"additional","affiliation":[{"name":"Center of Research, Education Innovation and Intervention in Sport and Porto Biomechanics Laboratory, Faculty of Sport, University of Porto, 4200-450 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1555-5079","authenticated-orcid":false,"given":"David B.","family":"Pyne","sequence":"additional","affiliation":[{"name":"Research Institute for Sport & Exercise, University of Canberra, Canberra 2617, Australia"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4996-1414","authenticated-orcid":false,"given":"Victor Machado","family":"Reis","sequence":"additional","affiliation":[{"name":"Department of Sport Sciences, Exercise and Health, University of Tr\u00e1s-os-Montes e Alto Douro, 5001-801 Vila Real, Portugal"},{"name":"Research Center in Sports Sciences, Health Sciences and Human Development, 5001-801 Vila Real, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7404-7405","authenticated-orcid":false,"given":"Daniel","family":"Moreira-Gon\u00e7alves","sequence":"additional","affiliation":[{"name":"Research Center in Physical Activity, Health and Leisure, Faculty of Sport, University of Porto, 4200-450 Porto, Portugal"},{"name":"Laboratory for Integrative and Translational Research in Population Health, 4050-091 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5811-0443","authenticated-orcid":false,"given":"Ricardo J.","family":"Fernandes","sequence":"additional","affiliation":[{"name":"Center of Research, Education Innovation and Intervention in Sport and Porto Biomechanics Laboratory, Faculty of Sport, University of Porto, 4200-450 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2024,1,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"62","DOI":"10.1249\/00005768-199002000-00011","article-title":"Physiological determinants of pulmonary gas exchange kinetics during exercise","volume":"22","author":"Whipp","year":"1990","journal-title":"Med. 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