{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T13:22:19Z","timestamp":1788182539689,"version":"build-2803163510"},"reference-count":43,"publisher":"Frontiers Media SA","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\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Physiol."],"abstract":"<jats:sec>\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>To identify data-driven Dmax-derived threshold-intensity profiles in adolescent swimmers by jointly considering pool-based and land-based incremental-test indicators and to examine hematological, performance-related, maturation-related, and psychoperceptual characteristics associated with profile membership.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>This multicenter cross-sectional study included 247 adolescent swimmers from three training centers. Participants completed a land-based cycling incremental test and a pool-based 5 \u00d7 200\u00a0m front-crawl incremental test. Pool-based Dmax-derived threshold intensity was expressed as swimming velocity at the Dmax point relative to event-specific personal-best velocity, whereas land-based Dmax-derived threshold power was expressed as cycling power output at the Dmax point. The two indicators were entered into latent profile analysis. Between-profile comparisons incorporated effect sizes, 95% confidence intervals, and Benjamini\u2013Hochberg adjustment for multiple testing. Candidate variables were selected according to prior evidence and biological plausibility, screened for strong pairwise correlations, and entered into a multinomial logistic regression model with study center included as a categorical fixed effect.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Three ordered threshold-intensity profiles were identified: lower (n = 117, 47.4%), intermediate (n = 72, 29.2%), and higher (n = 58, 23.5%). The selected model showed good classification accuracy (entropy = 0.929). Relative to the lower profile, membership in the intermediate profile was associated with a higher red blood cell count (OR = 7.765, 95% CI: 3.198\u201318.849), lower perceived exertion (OR = 0.500, 95% CI: 0.372\u20130.672), and greater last-repetition completion relative to personal-best velocity (OR = 1.725, 95% CI: 1.317\u20132.259). Membership in the higher profile was associated with a higher red blood cell count (OR = 40.412, 95% CI: 10.844\u2013150.605), lower perceived exertion (OR = 0.300, 95% CI: 0.197\u20130.457), greater last-repetition completion (OR = 2.903, 95% CI: 2.007\u20134.200), lower mental fatigue (OR = 0.954, 95% CI: 0.916\u20130.993), and greater sport mental toughness (OR = 1.134, 95% CI: 1.041\u20131.235).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Adolescent swimmers exhibited three data-driven, ordered patterns in the joint distribution of pool-based Dmax intensity and land-based Dmax power. Profile membership was associated with concurrent hematological, performance-related, and psychoperceptual characteristics. These profiles provide an exploratory person-centered framework for describing cross-modal threshold-intensity heterogeneity rather than biologically discrete phenotypes or prescriptive training categories. Their reliability, longitudinal stability, and responsiveness to training require further evaluation.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fphys.2026.1935422","type":"journal-article","created":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T13:07:20Z","timestamp":1788181640000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Dmax-derived lactate-threshold intensity profiles and associated factors in adolescent swimmers: a multicenter cross-sectional study"],"prefix":"10.3389","volume":"17","author":[{"given":"Jiayi","family":"Lyu","sequence":"first","affiliation":[{"name":"School of Education, Beijing Sport University","place":["Beijing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Guangnan","family":"Liu","sequence":"additional","affiliation":[{"name":"School of Clinical Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College","place":["Beijing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jiawen","family":"Li","sequence":"additional","affiliation":[{"name":"Yale College, Yale University","place":["New Haven, CT, United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lei","family":"Lei","sequence":"additional","affiliation":[{"name":"Beijing No.24 Middle School","place":["Beijing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ze","family":"Zhang","sequence":"additional","affiliation":[{"name":"Faculty of Arts and Education, The University of Auckland","place":["Auckland, New Zealand"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jie","family":"Gao","sequence":"additional","affiliation":[{"name":"School of Education, Beijing Sport University","place":["Beijing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,8,31]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"435","DOI":"10.1249\/00003677-199401000-00016","article-title":"Assessment and interpretation of aerobic fitness in children and adolescents","volume":"22","author":"Armstrong","year":"1994","journal-title":"Exercise Sport. 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