{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,25]],"date-time":"2026-08-25T06:23:36Z","timestamp":1787639016576,"version":"build-2736575974"},"reference-count":57,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,8,25]],"date-time":"2026-08-25T00:00:00Z","timestamp":1787616000000},"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. Behav. Neurosci."],"abstract":"\n Background<\/jats:title>\n Sex-related variation in psychological traits is usually studied as a categorical male\u2013female contrast, which conflates a grouping variable with the continuous biology underlying it. The second-to-fourth digit ratio (2D:4D) provides a non-invasive marker of the prenatal androgen environment, but its relationship with mental toughness and playing position in soccer remains poorly understood. This study examined the associations between 2D:4D-derived classification, playing position, sex and mental toughness, testing whether mental toughness tracks a continuous sex-related biological index rather than sex category alone.<\/jats:p>\n <\/jats:sec>\n \n Methods<\/jats:title>\n \n In a cross-sectional design, 270 licensed amateur soccer players (241 men, 29 women; aged 13\u201335 years) from Denizli, T\u00fcrkiye, were assessed. Mental toughness was measured with the Sports Mental Toughness Questionnaire (SMTQ). Digit lengths were measured directly on both hands with a calibrated digital caliper, and the two-hand mean ratio assigned each player to one of three operational categories at a cut-off of unity (Type A &lt; 1.00, Type C = 1.00, Type B &gt; 1.00). Data were analysed with one-way and two-way ANOVA with Bonferroni\n post-hoc<\/jats:italic>\n comparisons.\n <\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n \n Type B players reported higher mental toughness (\n M<\/jats:italic>\n = 47.36) than Type A (43.85) and Type C (44.24) players,\n F<\/jats:italic>\n (2, 267)<\/jats:sub>\n = 6.70,\n p<\/jats:italic>\n = 0.002, \u03b7\n 2<\/jats:sup>\n = 0.048. Defenders (45.34) scored higher than goalkeepers (41.13;\n p<\/jats:italic>\n = 0.021),\n F<\/jats:italic>\n (3, 266)<\/jats:sub>\n = 3.00,\n p<\/jats:italic>\n = 0.031, \u03b7\n 2<\/jats:sup>\n = 0.033. In the two-way model classification remained significant,\n F<\/jats:italic>\n (2, 258)<\/jats:sub>\n = 6.10,\n p<\/jats:italic>\n = 0.003, whereas position,\n F<\/jats:italic>\n (3, 258)<\/jats:sub>\n = 2.22,\n p<\/jats:italic>\n = 0.086, and the interaction,\n F<\/jats:italic>\n (6, 258)<\/jats:sub>\n = 0.81,\n p<\/jats:italic>\n = 0.560, did not. Male players scored higher than female players, t(268) = 1.99,\n p<\/jats:italic>\n = 0.047.\n <\/jats:p>\n <\/jats:sec>\n \n Conclusion<\/jats:title>\n Mental toughness varied with 2D:4D-derived classification and playing position, and the classification effect ran counter to a simple masculinization account, since the less androgenized Type B profile scored highest. A sex difference was also present, but classification and sex operated in opposing directions and neither was reducible to the other. Types A, B and C are operational classifications, not literal brain categories, and should be interpreted with caution.<\/jats:p>\n <\/jats:sec>","DOI":"10.3389\/fnbeh.2026.1934922","type":"journal-article","created":{"date-parts":[[2026,8,25]],"date-time":"2026-08-25T05:35:03Z","timestamp":1787636103000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Sex-related biological variation and mental toughness in soccer: a 2D:4D digit-ratio study of Type a, Type B and Type C classification across playing positions"],"prefix":"10.3389","volume":"20","author":[{"given":"Hamza Kaya","family":"Besler","sequence":"first","affiliation":[{"name":"Department of Sport Management, Faculty of Sports Sciences, Pamukkale University","place":["Denizli, T\u00fcrkiye"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gulferi M.","family":"Yildirim","sequence":"additional","affiliation":[{"name":"Department of Neuroscience, Uskudar University","place":["Istanbul, T\u00fcrkiye"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sinan","family":"Canan","sequence":"additional","affiliation":[{"name":"Acikbeyin Education and Consultancy","place":["Istanbul, T\u00fcrkiye"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sinan","family":"Seyhan","sequence":"additional","affiliation":[{"name":"Department of Coaching Education, Faculty of Sport Sciences, Manisa Celal Bayar University","place":["Manisa, T\u00fcrkiye"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"G\u00f6rkem","family":"A\u00e7ar","sequence":"additional","affiliation":[{"name":"Faculty of Sport Sciences, Istanbul Gelisim University","place":["Istanbul, T\u00fcrkiye"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Muhammed Fatih","family":"Bilici","sequence":"additional","affiliation":[{"name":"Faculty of Sport Sciences, Bitlis Eren University","place":["Bitlis, T\u00fcrkiye"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"U\u011fur","family":"S\u00f6nmezo\u011flu","sequence":"additional","affiliation":[{"name":"Department of Sport Management, Faculty of Sports Sciences, Pamukkale University","place":["Denizli, T\u00fcrkiye"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,8,25]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"132","DOI":"10.30472\/IJAEP.V8I1.326","article-title":"Analysis of the 2D: 4D ratios of national and amateur football players.","volume":"8","author":"Acar","year":"2019","journal-title":"Int. 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