{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T04:44:01Z","timestamp":1787805841431,"version":"build-2784847793"},"reference-count":31,"publisher":"National Athletic Trainers' Association","issue":"2","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2018,2,1]]},"abstract":"<jats:sec>\n                  <jats:title>Context:\u2003<\/jats:title>\n                  <jats:p>Subclinical postural-control changes may persist beyond the point when athletes are considered clinically recovered postconcussion.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Objective:\u2003<\/jats:title>\n                  <jats:p>To compare postural-control performance between former high school football players with or without a history of concussion using linear and nonlinear metrics.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Design:\u2003<\/jats:title>\n                  <jats:p>Case-control study.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Setting:\u2003<\/jats:title>\n                  <jats:p>Clinical research laboratory.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Patients or Other Participants:\u2003<\/jats:title>\n                  <jats:p>A total of 11 former high school football players (age range, 45\u201360 years) with 2 or more concussions and 11 age- and height-matched former high school football players without a history of concussion. No participant had college or professional football experience.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Main Outcome Measure(s):\u2003<\/jats:title>\n                  <jats:p>Participants completed the Sensory Organization Test. We compared postural control (linear: equilibrium scores; nonlinear: sample and multiscale entropy) between groups using a 2 \u00d7 3 analysis of variance across conditions 4 to 6 (4: eyes open, sway-referenced platform; 5: eyes closed, sway-referenced platform; 6: eyes open, sway-referenced surround and platform).<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Results:\u2003<\/jats:title>\n                  <jats:p>We observed a group-by-condition interaction effect for medial-lateral sample entropy (F2,40 = 3.26, P = .049, \u03b7p2 = 0.140). Participants with a history of concussion presented with more regular medial-lateral sample entropy values (0.90 \u00b1 0.41) for condition 5 than participants without a history of concussion (1.30 \u00b1 0.35; mean difference = \u22120.40; 95% confidence interval [CI] = \u22120.74, \u22120.06; t20 = \u22122.48, P = .02), but conditions 4 (mean difference = \u22120.11; 95% CI: \u22120.37, 0.15; t20 = \u22120.86, P = .40) and 6 (mean difference = \u22120.25; 95% CI: \u22120.55, 0.06; t20 = \u22121.66, P = .11) did not differ between groups.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Conclusions:\u2003<\/jats:title>\n                  <jats:p>Postconcussion deficits, detected using nonlinear metrics, may persist long after injury resolution. Subclinical concussion deficits may persist for years beyond clinical concussion recovery.<\/jats:p>\n               <\/jats:sec>","DOI":"10.4085\/1062-6050-326-16","type":"journal-article","created":{"date-parts":[[2018,1,13]],"date-time":"2018-01-13T17:30:01Z","timestamp":1515864601000},"page":"109-114","source":"Crossref","is-referenced-by-count":23,"title":["Balance Regularity Among Former High School Football Players With or Without a History of Concussion"],"prefix":"10.4085","volume":"53","author":[{"given":"Julianne D.","family":"Schmidt","sequence":"first","affiliation":[{"name":"University of Georgia, Athens"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Douglas P.","family":"Terry","sequence":"first","affiliation":[{"name":"University of Georgia, Athens"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jihyun","family":"Ko","sequence":"first","affiliation":[{"name":"Seoul National University, South Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Karl M.","family":"Newell","sequence":"first","affiliation":[{"name":"University of Georgia, Athens"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"L. 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Clackamas, OR: Neurocom International Inc; 1991."},{"key":"2020060411161159500_i1062-6050-53-2-109-b21","first-page":"451","article-title":"Computerized dynamic posturography","author":"Nashner","year":"2016","journal-title":"Balance Function Assessment and Management. 2nd ed"},{"issue":"2","key":"2020060411161159500_i1062-6050-53-2-109-b22","doi-asserted-by":"crossref","first-page":"349","DOI":"10.1007\/s10439-012-0668-3","article-title":"The appropriate use of approximate entropy and sample entropy with short data sets","volume":"41","author":"Yentes","year":"2013","journal-title":"Ann Biomed Eng"},{"issue":"2","key":"2020060411161159500_i1062-6050-53-2-109-b23","doi-asserted-by":"crossref","first-page":"530","DOI":"10.1152\/jappl.1999.87.2.530","article-title":"Human fetuses have nonlinear cardiac dynamics","volume":"87","author":"Groome","year":"1999","journal-title":"J Appl Physiol"},{"issue":"3","key":"2020060411161159500_i1062-6050-53-2-109-b24","doi-asserted-by":"crossref","first-page":"431","DOI":"10.1007\/s11071-011-0281-2","article-title":"Entropy measures for biological signal analyses","volume":"68","author":"Gao","year":"2012","journal-title":"Nonlinear Dyn"},{"key":"2020060411161159500_i1062-6050-53-2-109-b25","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1016\/j.physa.2003.08.022","article-title":"Multiscale entropy analysis of human gait dynamics","volume":"330","author":"Costa","year":"2003","journal-title":"Physica A"},{"issue":"6","key":"2020060411161159500_i1062-6050-53-2-109-b26","doi-asserted-by":"crossref","first-page":"68008","DOI":"10.1209\/0295-5075\/77\/68008","article-title":"Noise and poise: enhancement of postural complexity in the elderly with a stochastic-resonance-based therapy","volume":"77","author":"Costa","year":"2007","journal-title":"Europhys Lett"},{"issue":"13","key":"2020060411161159500_i1062-6050-53-2-109-b27","doi-asserted-by":"crossref","first-page":"1806","DOI":"10.1001\/jama.1992.03480130122036","article-title":"Loss of \u201ccomplexity\u201d and aging: potential applications of fractals and chaos theory to senescence","volume":"267","author":"Lipsitz","year":"1992","journal-title":"JAMA"},{"issue":"1","key":"2020060411161159500_i1062-6050-53-2-109-b28","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1159\/000089820","article-title":"Force platform measurements as predictors of falls among older people: a review","volume":"52","author":"Piirtola","year":"2006","journal-title":"Gerontology"},{"issue":"3","key":"2020060411161159500_i1062-6050-53-2-109-b29","doi-asserted-by":"crossref","first-page":"742","DOI":"10.1177\/0363546515622387","article-title":"Concussion increases odds of sustaining a lower extremity musculoskeletal injury after return to play among collegiate athletes","volume":"44","author":"Brooks","year":"2016","journal-title":"Am J Sports Med"},{"issue":"11","key":"2020060411161159500_i1062-6050-53-2-109-b30","doi-asserted-by":"crossref","first-page":"2366","DOI":"10.1249\/MSS.0000000000000684","article-title":"Concussion frequency associates with musculoskeletal injury in retired NFL players","volume":"47","author":"Pietrosimone","year":"2015","journal-title":"Med Sci Sports Exerc"},{"issue":"12","key":"2020060411161159500_i1062-6050-53-2-109-b31","doi-asserted-by":"crossref","first-page":"2487","DOI":"10.1249\/MSS.0000000000000716","article-title":"Acute lower extremity injury rates increase after concussion in college athletes","volume":"47","author":"Lynall","year":"2015","journal-title":"Med Sci Sports Exerc"}],"container-title":["Journal of Athletic Training"],"original-title":[],"language":"en","link":[{"URL":"http:\/\/meridian.allenpress.com\/jat\/article-pdf\/53\/2\/109\/1617148\/1062-6050-326-16.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"http:\/\/meridian.allenpress.com\/jat\/article-pdf\/53\/2\/109\/1617148\/1062-6050-326-16.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,6,11]],"date-time":"2025-06-11T18:54:59Z","timestamp":1749668099000},"score":1,"resource":{"primary":{"URL":"https:\/\/nata.kglmeridian.com\/view\/journals\/attr\/53\/2\/article-p109.xml"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,2,1]]},"references-count":31,"journal-issue":{"issue":"2","published-print":{"date-parts":[[2018,2,1]]}},"URL":"https:\/\/doi.org\/10.4085\/1062-6050-326-16","relation":{},"ISSN":["1062-6050"],"issn-type":[{"value":"1062-6050","type":"print"}],"subject":[],"published":{"date-parts":[[2018,2,1]]}}}