{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,5]],"date-time":"2026-09-05T05:16:57Z","timestamp":1788585417377,"version":"build-2803163510"},"reference-count":40,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T00:00:00Z","timestamp":1788134400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001659","name":"Deutsche Forschungsgemeinschaft","doi-asserted-by":"publisher","award":["516547656"],"award-info":[{"award-number":["516547656"]}],"id":[{"id":"10.13039\/501100001659","id-type":"DOI","asserted-by":"publisher"}]},{"award":["516547656"],"award-info":[{"award-number":["516547656"]}],"id":[{"id":"https:\/\/ror.org\/018mejw64","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Int. J. Mol. Sci.","IJMS"],"abstract":"<jats:p>Resting antioxidant enzyme activity in youth athletes may reflect stable individual redox characteristics and developmentally modulated plasticity. This 12-month longitudinal analysis from the MuCAYAplus study examined the tracking of superoxide dismutase (SOD) and glutathione peroxidase (GPX) in 69 trained athletes aged 10\u201317 years. Participants underwent repeated assessments of antioxidant enzyme activity, training exposure, body composition, and hematological parameters. Longitudinal tracking was evaluated using Pearson correlation and intraclass correlation coefficients, while change-score regression models tested whether changes in training exposure, growth-related variables, sex interactions, and hematological parameters predicted changes in SOD or GPX. In exploratory analyses, cluster-based redox phenotype stability was assessed using agreement statistics. Over 12 months, SOD decreased whereas GPX increased. GPX showed substantial tracking (r = 0.714, p &lt; 0.001; ICC = 0.683), while SOD showed no meaningful tracking (r = 0.057, p = 0.644; ICC = 0.053). No statistically supported associations were detected between changes in training-exposure or growth-related measures and enzyme changes. Exploratory erythrocyte-related associations were observed for SOD, whereas leukocyte and platelet changes were unrelated. Cluster-based SOD\/GPX phenotype analyses were not robust. These findings are compatible with a comparatively stronger trait-like component for GPX and greater state-like variability for SOD.<\/jats:p>","DOI":"10.3390\/ijms27177813","type":"journal-article","created":{"date-parts":[[2026,9,1]],"date-time":"2026-09-01T09:48:36Z","timestamp":1788256116000},"page":"7813","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Enzyme-Specific Redox Stability and Plasticity in Trained Youth Athletes: Longitudinal Analysis of SOD and GPX"],"prefix":"10.3390","volume":"27","author":[{"given":"Jonas","family":"Haferanke","sequence":"first","affiliation":[{"name":"Institute of Preventive Pediatrics, Department Health and Sport Sciences, TUM School of Medicine and Health, Technical University of Munich (TUM), 80809 Munich, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-1733-6360","authenticated-orcid":false,"given":"Maximilian","family":"Dettenhofer","sequence":"additional","affiliation":[{"name":"Institute of Preventive Pediatrics, Department Health and Sport Sciences, TUM School of Medicine and Health, Technical University of Munich (TUM), 80809 Munich, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-0757-7681","authenticated-orcid":false,"given":"Stefanie","family":"Huber","sequence":"additional","affiliation":[{"name":"Institute of Preventive Pediatrics, Department Health and Sport Sciences, TUM School of Medicine and Health, Technical University of Munich (TUM), 80809 Munich, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Frauke","family":"M\u00fchlbauer","sequence":"additional","affiliation":[{"name":"Institute of Preventive Pediatrics, Department Health and Sport Sciences, TUM School of Medicine and Health, Technical University of Munich (TUM), 80809 Munich, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lisa","family":"Baumgartner","sequence":"additional","affiliation":[{"name":"Institute of Preventive Pediatrics, Department Health and Sport Sciences, TUM School of Medicine and Health, Technical University of Munich (TUM), 80809 Munich, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6251-9532","authenticated-orcid":false,"given":"Tobias","family":"Engl","sequence":"additional","affiliation":[{"name":"Institute of Preventive Pediatrics, Department Health and Sport Sciences, TUM School of Medicine and Health, Technical University of Munich (TUM), 80809 Munich, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Thorsten","family":"Schulz","sequence":"additional","affiliation":[{"name":"Institute of Preventive Pediatrics, Department Health and Sport Sciences, TUM School of Medicine and Health, Technical University of Munich (TUM), 80809 Munich, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3166-0488","authenticated-orcid":false,"given":"Renate","family":"Oberhoffer","sequence":"additional","affiliation":[{"name":"Institute of Preventive Pediatrics, Department Health and Sport Sciences, TUM School of Medicine and Health, Technical University of Munich (TUM), 80809 Munich, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0000-3755-6481","authenticated-orcid":false,"given":"Sebastian","family":"Freilinger","sequence":"additional","affiliation":[{"name":"Institute of Preventive Pediatrics, Department Health and Sport Sciences, TUM School of Medicine and Health, Technical University of Munich (TUM), 80809 Munich, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,31]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1097\/MED.0b013e328320d54c","article-title":"Effect of puberty on body composition","volume":"16","author":"Styne","year":"2009","journal-title":"Curr. 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