{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,23]],"date-time":"2026-07-23T14:19:59Z","timestamp":1784816399844,"version":"3.55.0"},"reference-count":45,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2024,11,12]],"date-time":"2024-11-12T00:00:00Z","timestamp":1731369600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Departamento de Ciencia, Universidad y Sociedad del Conocimiento, from the Gobierno de Arag\u00f3n (Spain)","award":["S08_23R"],"award-info":[{"award-number":["S08_23R"]}]},{"name":"Departamento de Ciencia, Universidad y Sociedad del Conocimiento, from the Gobierno de Arag\u00f3n (Spain)","award":["FPU 19\/00967"],"award-info":[{"award-number":["FPU 19\/00967"]}]},{"name":"Spanish Ministry of Universities","award":["S08_23R"],"award-info":[{"award-number":["S08_23R"]}]},{"name":"Spanish Ministry of Universities","award":["FPU 19\/00967"],"award-info":[{"award-number":["FPU 19\/00967"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JFMK"],"abstract":"<jats:p>Background: Research into key performance factors in trail running, particularly in vertical kilometer (VK) races, is crucial for effective training and periodization. However, recent studies on metabolic and cardiorespiratory responses during VK races, especially using field tests, are limited. Objectives: Therefore, the aim of this study is to evaluate the metabolic and cardiorespiratory responses during a VK field test, identifying differences based on sex and performance level, as well as key performance factors and their deterioration due to fatigue. Fifteen trained trail runners (ten males and five females, 19 to 38 years old) perform a VK race. Methods: The global physiological response is evaluated using the portable gas analyzer Cosmed K5 and the local response using near-infrared spectroscopy technology. Results: In gender comparisons, the ANCOVA test shows significant differences (p &lt; 0.05) in the ventilation, tidal volume, expiratory time-to-inspiratory time ratio, inspiratory flow rate, end-tidal CO2 partial pressure, heart rate, oxygen pulse, and total hemoglobin. Additionally, the performance comparison reveals significant differences in the variables\u2019 velocity, oxygen consumption, carbon dioxide production, ventilation, dead space-to-tidal volume ratio, total time of the breathing cycle, expiratory time-to-inspiratory time ratio, inspiratory duty cycle, expiratory fractions of CO2, quadriceps saturation index, and VE\/VCO2 ratio. Finally, the correlation analysis shows oxygen consumption (r = \u22120.80 mean; r = \u22120.72 peak), carbon dioxide production (r = \u22120.91 mean; r = \u22120.75 peak), expiratory time-to-inspiratory time ratio (r = 0.68 peak), ventilation (r = \u22120.58 mean), and quadriceps saturation index (r = 0.54 mean; r = \u22120.76 coefficient of variation) as the key performance factors in the VK race. Conclusions: Overall, the physiological analysis indicates the importance of local muscular adaptations and respiratory system capacity in this type of short-duration race.<\/jats:p>","DOI":"10.3390\/jfmk9040230","type":"journal-article","created":{"date-parts":[[2024,11,12]],"date-time":"2024-11-12T09:36:51Z","timestamp":1731404211000},"page":"230","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Study of Physiological Adaptations in Vertical Kilometer Runners: Focus on Cardiorespiratory and Local Muscle Demands"],"prefix":"10.3390","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8770-2106","authenticated-orcid":false,"given":"Pablo Jes\u00fas","family":"Bascuas","sequence":"first","affiliation":[{"name":"Facultad de Ciencias de la Salud, Universidad San Jorge, Autov. A-23 Zaragoza-Huesca, KM 299, 50830 Villanueva de G\u00e1llego, Zaragoza, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0411-2945","authenticated-orcid":false,"given":"H\u00e9ctor","family":"Guti\u00e9rrez","sequence":"additional","affiliation":[{"name":"Facultad de Ciencias de la Salud, Universidad San Jorge, Autov. A-23 Zaragoza-Huesca, KM 299, 50830 Villanueva de G\u00e1llego, Zaragoza, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6349-2370","authenticated-orcid":false,"given":"Eduardo","family":"Piedrafita","sequence":"additional","affiliation":[{"name":"Facultad de Ciencias de la Salud, Universidad San Jorge, Autov. A-23 Zaragoza-Huesca, KM 299, 50830 Villanueva de G\u00e1llego, Zaragoza, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6368-875X","authenticated-orcid":false,"given":"Ana Vanessa","family":"Bataller-Cervero","sequence":"additional","affiliation":[{"name":"Facultad de Ciencias de la Salud, Universidad San Jorge, Autov. A-23 Zaragoza-Huesca, KM 299, 50830 Villanueva de G\u00e1llego, Zaragoza, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7783-6672","authenticated-orcid":false,"given":"C\u00e9sar","family":"Berzosa","sequence":"additional","affiliation":[{"name":"Facultad de Ciencias de la Salud, Universidad San Jorge, Autov. A-23 Zaragoza-Huesca, KM 299, 50830 Villanueva de G\u00e1llego, Zaragoza, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,11,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"819","DOI":"10.1055\/s-0043-112342","article-title":"Performance Factors in a Mountain Ultramarathon","volume":"38","author":"Balducci","year":"2017","journal-title":"Int. J. Sports Med."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"615","DOI":"10.1007\/s40279-016-0605-y","article-title":"Biomechanics and Physiology of Uphill and Downhill Running","volume":"47","author":"Vernillo","year":"2017","journal-title":"Sports Med."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"275","DOI":"10.1152\/japplphysiol.00563.2010","article-title":"The Two-Hour Marathon: Who and When?","volume":"110","author":"Joyner","year":"2011","journal-title":"J. Appl. 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