{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T21:01:11Z","timestamp":1792789271572,"version":"4.5.0"},"reference-count":35,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T00:00:00Z","timestamp":1789603200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Istanbul Gedik University","award":["GDK202410-09"],"award-info":[{"award-number":["GDK202410-09"]}],"id":[{"id":"https:\/\/ror.org\/05msvfx67","id-type":"ROR","asserted-by":"crossref"}]},{"award":["GDK202410-09"],"award-info":[{"award-number":["GDK202410-09"]}],"id":[{"id":"https:\/\/ror.org\/05msvfx67","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Genes"],"abstract":"<jats:p>Background: Endurance performance reflects integrated cardiorespiratory, metabolic and musculoskeletal traits with substantial heritability, yet sex-balanced studies that simultaneously deep-phenotype athletes and genotype candidate loci against trained comparators remain scarce. Objective: We aim to characterize the integrated physiological profile and genotype distributions at five endurance-relevant polymorphisms in elite versus recreationally trained runners. Methods: Eighty runners (20 elite male, 20 elite female, 20 recreational male, 20 recreational female) completed graded treadmill testing with breath-by-breath gas exchange and capillary blood lactate sampling, together with whole-body dual-energy X-ray absorptiometry. A sub-sample of 40 participants (10 per subgroup) underwent next-generation sequencing of ACTN3 R577X, VEGFA rs699947, PPARGC1A Gly482Ser, ACE I\/D and PPARG Pro12Ala. Physiology was compared using one-way ANOVA with Tukey\u2019s HSD and Cohen\u2019s d; genotype distributions were compared using Monte Carlo exact tests with Benjamini\u2013Hochberg correction. Results: Elite runners exhibited higher VO2max (elite male 71.8 \u00b1 4.9; elite female 65.3 \u00b1 3.6 mL\u00b7kg\u22121\u00b7min\u22121; both vs. same-sex controls, p &lt; 0.001; \u03b72 = 0.62), superior running economy (\u03b72 = 0.76), lactate thresholds shifted rightward by ~1 km\u00b7h\u22121, and more favorable body composition (lean mass \u03b72 = 0.80; body fat \u03b72 = 0.48). Principal component analysis separated elites from recreational runners along PC1 (40.1% variance) in both sexes. Effect-allele frequencies were numerically higher in elites at every locus (odds ratios 1.48\u20132.03), but no genotype \u00d7 group association survived correction (all q \u2265 0.82). Conclusions: Elite endurance status was robustly distinguished by an integrated physiological phenotype with large effect sizes. Effect-allele frequencies at five candidate loci were numerically higher in the expected direction but did not reach statistical significance; given the small genotyped sub-sample, these genetic data are purely exploratory and hypothesis-generating and require replication in adequately powered cohorts.<\/jats:p>","DOI":"10.3390\/genes17091133","type":"journal-article","created":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T08:03:17Z","timestamp":1789632197000},"page":"1133","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Beyond VO2max: Integrated Physiological Phenotyping and Candidate-Gene Analysis of Elite Versus Recreational Endurance Runners"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6900-1955","authenticated-orcid":false,"given":"Hasan U\u011fur","family":"\u00d6ncel","sequence":"first","affiliation":[{"name":"Department of Nutrition and Dietetics, Faculty of Health Sciences, Istanbul Gedik University, Kartal, Istanbul 34876, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1346-4982","authenticated-orcid":false,"given":"Jason","family":"Siegler","sequence":"additional","affiliation":[{"name":"Integrative Human Performance Lab, College of Health Solutions, Arizona State University, Phoenix, AZ 85004, USA"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"}]},{"given":"Alper","family":"\u00d6zkan","sequence":"additional","affiliation":[{"name":"Department of Cardiology, Ac\u0131badem Hospital, Istanbul 34149, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"investigation","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"}]},{"given":"Okan","family":"O\u011ful","sequence":"additional","affiliation":[{"name":"Department of Nutrition and Dietetics, Faculty of Health Sciences, Istanbul Gedik University, Kartal, Istanbul 34876, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"data-curation","vocabulary":"credit"}]},{"given":"Mikail","family":"Yal\u00e7\u0131n","sequence":"additional","affiliation":[{"name":"Department of Sports Coaching, Faculty of Sports Sciences, Istanbul Gedik University, Istanbul 34906, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"data-curation","vocabulary":"credit"}]},{"given":"\u015eahabettin","family":"Karabulut","sequence":"additional","affiliation":[{"name":"Department of Sports Coaching, Faculty of Sports Sciences, Istanbul Gedik University, Istanbul 34906, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"data-curation","vocabulary":"credit"},{"role":"software","vocabulary":"credit"}]},{"given":"R\u0131fat","family":"G\u00fclmez","sequence":"additional","affiliation":[{"name":"Department of Sports Coaching, Faculty of Sports Sciences, Istanbul Gedik University, Istanbul 34906, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"data-curation","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5379-3567","authenticated-orcid":false,"given":"Seyed Houtan","family":"Shahidi","sequence":"additional","affiliation":[{"name":"Department of Sports Coaching, Faculty of Sports Sciences, Istanbul Gedik University, Istanbul 34906, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"data-curation","vocabulary":"credit"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"software","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Shahidi, S.H. 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