{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,8]],"date-time":"2026-04-08T10:49:02Z","timestamp":1775645342456,"version":"3.50.1"},"reference-count":34,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2026,4,6]],"date-time":"2026-04-06T00:00:00Z","timestamp":1775433600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Scientific Research Projects Coordination Unit of Istanbul Yeni Yuzyil University"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This study aimed to identify distinct lactate kinetic phenotypes in professional soccer players using unsupervised machine learning and determine their relationship with maximal running velocity (Vmax) through explainable artificial intelligence methods. A total of 361 professional male soccer players from the First Division participated in the study. Incremental treadmill tests measured lactate concentrations at five standardized velocities, alongside VO2max, Vmax, lactate threshold (LT), and anaerobic threshold (AT) parameters. Three distinct lactate kinetic phenotypes emerged: Economical Aerobic (n = 216), Balanced Metabolic (n = 19), and High Producer (n = 126). The Economical Aerobic phenotype demonstrated superior performance metrics compared to High Producer (Vmax: 15.85 \u00b1 0.85 km\/h; VO2max: 56.20 \u00b1 4.26 mL\/kg\/min; p &lt; 0.001). Initial multicollinearity assessment revealed notable collinearity among all 10 candidate predictors (VIF &gt; 10; maximum VIF = 10.75 for VAT), necessitating rigorous feature selection. Ridge regression with 4 selected features (VAT, VO2max, 9.5 km\/h lactate, 14 km\/h lactate) achieved moderate but statistically significant predictive performance: 10-fold cross-validation R2= 0.392 \u00b1 0.147 (permutation test p = 0.001). Standardized coefficients identified VAT (\u03b2 = 0.399) as the dominant predictor, followed by VO2max (\u03b2 = 0.253), 9.5 km\/h lactate (\u03b2 = 0.107), and 14 km\/h lactate (\u03b2 = \u22120.066). Lactate kinetic phenotyping reveals position-independent metabolic profiles with potentially meaningful performance associations in professional soccer. The Economical Aerobic phenotype demonstrates performance advantages associated with superior anaerobic threshold capacity. These exploratory findings suggest that individualized training strategies based on metabolic phenotype rather than playing position alone warrant further investigation, with potential applications for talent identification, training periodization, and return-to-play protocols pending prospective validation.<\/jats:p>","DOI":"10.3390\/s26072252","type":"journal-article","created":{"date-parts":[[2026,4,6]],"date-time":"2026-04-06T08:58:48Z","timestamp":1775465928000},"page":"2252","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Position-Independent Lactate Kinetic Phenotypes in Professional Soccer Players: A Machine Learning Approach for Maximal Running Velocity Prediction"],"prefix":"10.3390","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2816-9994","authenticated-orcid":false,"given":"Erkan","family":"Tortu","sequence":"first","affiliation":[{"name":"Department of Coaching Education, Faculty of Sport Sciences, Trabzon University, 61335 Trabzon, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6566-5201","authenticated-orcid":false,"given":"\u0130zzet","family":"\u0130nce","sequence":"additional","affiliation":[{"name":"Department of Coaching Education, Faculty of Sport Sciences, Ankara Yildirim Beyazit University, 06010 Ankara, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4148-9781","authenticated-orcid":false,"given":"Salih","family":"\u00c7abuk","sequence":"additional","affiliation":[{"name":"Department of Coaching Education, Faculty of Sport Sciences, Erzurum Technical University, 25050 Erzurum, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9466-5278","authenticated-orcid":false,"given":"S\u00fcleyman","family":"Ulup\u0131nar","sequence":"additional","affiliation":[{"name":"Department of Coaching Education, Faculty of Sport Sciences, Erzurum Technical University, 25050 Erzurum, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0990-9224","authenticated-orcid":false,"given":"Cebrail","family":"Gen\u00e7o\u011flu","sequence":"additional","affiliation":[{"name":"Department of Coaching Education, Faculty of Sport Sciences, Erzurum Technical University, 25050 Erzurum, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6424-8871","authenticated-orcid":false,"given":"Serhat","family":"\u00d6zbay","sequence":"additional","affiliation":[{"name":"Department of Physical Education and Sports, Faculty of Sport Sciences, Erzurum Technical University, 25050 Erzurum, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0892-645X","authenticated-orcid":false,"given":"Kaan","family":"Kaya","sequence":"additional","affiliation":[{"name":"Department of Coaching Education, Faculty of Sport Sciences, Istanbul Yeni Yuzyil University, 34010 Istanbul, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,4,6]]},"reference":[{"key":"ref_1","first-page":"1","article-title":"The physiology of soccer\u2014With special reference to intense intermittent exercise","volume":"619","author":"Bangsbo","year":"1994","journal-title":"Acta Physiol. Scand. Suppl."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"501","DOI":"10.2165\/00007256-200535060-00004","article-title":"Physiology of soccer: An update","volume":"35","author":"Chamari","year":"2005","journal-title":"Sports Med."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"665","DOI":"10.1080\/02640410500482529","article-title":"Physical and metabolic demands of training and match-play in the elite football player","volume":"24","author":"Bangsbo","year":"2006","journal-title":"J. Sports Sci."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Bassett, D.R. (2000). Limiting factors for maximum oxygen uptake and determinants of endurance performance. Med. Sci. Sports Exerc., 32.","DOI":"10.1097\/00005768-200001000-00012"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"160","DOI":"10.1055\/s-2008-1034604","article-title":"Lactate kinetics and individual anaerobic threshold","volume":"2","author":"Stegmann","year":"1981","journal-title":"Int. J. Sports Med."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Schwesig, R., Schulze, S., Reinhardt, L., Laudner, K.G., Delank, K.S., and Hermassi, S. (2019). Differences in player position running velocity at lactate thresholds among male professional German soccer players. Front. Physiol., 10.","DOI":"10.3389\/fphys.2019.00886"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"252","DOI":"10.1097\/00005768-199802000-00013","article-title":"Familial resemblance for VO2maxin the sedentary state: The HERITAGE family study","volume":"30","author":"Bouchard","year":"1998","journal-title":"Med. Sci. Sports Exerc."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"173","DOI":"10.1123\/ijspp.2013-0026","article-title":"A common polymorphism of the MCT1 gene and athletic performance","volume":"9","author":"Fedotovskaya","year":"2014","journal-title":"Int. J. Sports Physiol. Perform."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"270","DOI":"10.1123\/ijspp.2018-0935","article-title":"Internal and external training load: 15 years on","volume":"14","author":"Impellizzeri","year":"2019","journal-title":"Int. J. Sports Physiol. Perform."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Claudino, J.G., Capanema, D.O., de Souza, T.V., Serr\u00e3o, J.C., Pereira, A.C.M., and Nassis, G.P. (2019). Current approaches to the use of artificial intelligence for injury risk assessment and performance prediction in team sports: A systematic review. Sports Med. Open, 5.","DOI":"10.1186\/s40798-019-0202-3"},{"key":"ref_11","first-page":"100","article-title":"Algorithm AS 136: A k-means clustering algorithm","volume":"28","author":"Hartigan","year":"1979","journal-title":"J. R. Stat. Soc. Ser. C Appl. Stat."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1016\/0377-0427(87)90125-7","article-title":"Silhouettes: A graphical aid to the interpretation and validation of cluster analysis","volume":"20","author":"Rousseeuw","year":"1987","journal-title":"J. Comput. Appl. Math."},{"key":"ref_13","first-page":"4768","article-title":"A unified approach to interpreting model predictions","volume":"30","author":"Lundberg","year":"2017","journal-title":"Adv. Neural Inf. Process. Syst."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Harrell, F.E. (2015). Regression Modeling Strategies: With Applications to Linear Models, Logistic and Ordinal Regression, and Survival Analysis, Springer. [2nd ed.].","DOI":"10.1007\/978-3-319-19425-7"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"276","DOI":"10.1016\/j.jsams.2012.08.003","article-title":"Effect of stage duration on maximal heart rate and post-exercise blood lactate concentration during incremental treadmill tests","volume":"16","author":"Machado","year":"2013","journal-title":"J. Sci. Med. Sport"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Bennett, T., Marshall, P., Barrett, S., Malone, J.J., Simpson, A., Bray, J., Christopherson, C., Nickolay, T., Metcalfe, J., and Towlson, C. (2024). Validation of field-based running tests to determine maximal aerobic speed in professional rugby league. PLoS ONE, 19.","DOI":"10.1371\/journal.pone.0306062"},{"key":"ref_17","first-page":"838","article-title":"Effects of supervised cardiovascular training program on exercise tolerance, aerobic capacity, and quality of life in patients with systemic lupus erythematosus","volume":"53","author":"Carvalho","year":"2005","journal-title":"Arthritis Care Res. Off. J. Am. Coll. Rheumatol."},{"key":"ref_18","first-page":"2496","article-title":"The examination of VO2MAX and anaerobic threshold values in elite soccer players by their positions","volume":"22","author":"Aksoy","year":"2022","journal-title":"J. Phys. Educ. Sport"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"2864","DOI":"10.1519\/JSC.0000000000001368","article-title":"Analysis of agreement between 4 lactate threshold measurements methods in professional soccer players","volume":"30","author":"Andrade","year":"2016","journal-title":"J. Strength Cond. Res."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1055\/s-2008-1025824","article-title":"Justification of the 4-mmol\/l lactate threshold","volume":"6","author":"Heck","year":"1985","journal-title":"Int. J. Sports Med."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"486","DOI":"10.1055\/s-2003-42020","article-title":"Effects of stage duration in incremental running tests on physiological variables","volume":"24","author":"Kuipers","year":"2003","journal-title":"Int. J. Sports Med."},{"key":"ref_22","first-page":"2825","article-title":"Scikit-learn: Machine learning in Python","volume":"12","author":"Pedregosa","year":"2011","journal-title":"J. Mach. Learn. Res."},{"key":"ref_23","unstructured":"Arthur, D., and Vassilvitskii, S. (2006, January 7\u20139). k-means++: The advantages of careful seeding. Proceedings of the Eighteenth Annual ACM-SIAM Symposium on Discrete Algorithms, New Orleans, LA, USA."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Cohen, J. (2013). Statistical Power Analysis for the Behavioral Sciences, Routledge.","DOI":"10.4324\/9780203771587"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"James, G. (2013). An Introduction to Statistical Learning: With Applications in R, Springer.","DOI":"10.1007\/978-1-4614-7138-7_2"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"55","DOI":"10.1080\/00401706.1970.10488634","article-title":"Ridge regression: Biased estimation for nonorthogonal problems","volume":"12","author":"Hoerl","year":"1970","journal-title":"Technometrics"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"469","DOI":"10.2165\/00007256-200939060-00003","article-title":"Lactate threshold concepts: How valid are they?","volume":"39","author":"Faude","year":"2009","journal-title":"Sports Med."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1160","DOI":"10.1152\/japplphysiol.00973.2010","article-title":"Genomic predictors of the maximal O2 uptake response to standardized exercise training programs","volume":"110","author":"Bouchard","year":"2011","journal-title":"J. Appl. Physiol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"625","DOI":"10.1080\/02640414.2012.665940","article-title":"Straight sprinting is the most frequent action in goal situations in professional football","volume":"30","author":"Faude","year":"2012","journal-title":"J. Sports Sci."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1925","DOI":"10.1097\/00005768-200111000-00019","article-title":"Aerobic endurance training improves soccer performance","volume":"33","author":"Helgerud","year":"2001","journal-title":"Med. Sci. Sports Exerc."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Strobl, C., Boulesteix, A.L., Zeileis, A., and Hothorn, T. (2007). Bias in random forest variable importance measures: Illustrations, sources and a solution. BMC Bioinform., 8.","DOI":"10.1186\/1471-2105-8-25"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"170","DOI":"10.1249\/MSS.0b013e3181ae5cfd","article-title":"Energy cost and metabolic power in elite soccer: A new match analysis approach","volume":"42","author":"Osgnach","year":"2010","journal-title":"Med. Sci. Sports Exerc."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"432","DOI":"10.1123\/ijspp.2013-0121","article-title":"The role and development of sprinting speed in soccer","volume":"9","author":"Haugen","year":"2014","journal-title":"Int. J. Sports Physiol. Perform."},{"key":"ref_34","unstructured":"MacArthur, D.G., and North, K.N. (2007). Genes and human elite athletic performance. East African Running, Routledge."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/26\/7\/2252\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,8]],"date-time":"2026-04-08T09:53:38Z","timestamp":1775642018000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/26\/7\/2252"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,4,6]]},"references-count":34,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2026,4]]}},"alternative-id":["s26072252"],"URL":"https:\/\/doi.org\/10.3390\/s26072252","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4,6]]}}}