{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T18:08:19Z","timestamp":1788890899691,"version":"build-2803163510"},"reference-count":43,"publisher":"Public Library of Science (PLoS)","issue":"9","license":[{"start":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T00:00:00Z","timestamp":1788825600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS One"],"abstract":"<jats:sec id=\"sec001\">\n                    <jats:title>Background\/Objective<\/jats:title>\n                    <jats:p>To investigate whether morphological abnormalities of the patellar tendon, assessed using ultrasound imaging, are associated with patellar tendon-related pain in adolescent soccer players.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sec002\">\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>This cross-sectional observational study was conducted at a university and enrolled 140 middle school soccer players (280 knees). Pain assessment was conducted using the visual analog scale and tenderness. Physical function assessments were also conducted. Ultrasound imaging was used to evaluate the morphology of the patellar tendon.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sec003\">\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Data on a total of 211 knees were analyzed. Compared with non-painful knees, knees with patellar tendon-related pain exhibited significantly lower knee extension strength and a higher prevalence of hypoechoic and Doppler findings. The logistic regression analysis demonstrated a significant association between hypoechoic findings and patellar tendon-related pain (adjusted odds ratio\u2009=\u200910.65, 95% confidence interval: 3.65\u201331.88, p\u2009&lt;\u20090.001), whereas no significant associations were observed for other morphological or physical function measures.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sec004\">\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Hypoechoic findings in the patellar tendon were significantly associated with patellar tendon-related pain in adolescent soccer players. These findings suggest that ultrasound imaging may be useful for identifying tendon characteristics that are associated with pain. However, longitudinal studies are needed to establish causal relationships.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1371\/journal.pone.0357407","type":"journal-article","created":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T17:33:08Z","timestamp":1788888788000},"page":"e0357407","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":0,"title":["Association between patellar tendon-related pain and morphological abnormalities of the patellar tendon visualized using ultrasound imaging in middle school athletes"],"prefix":"10.1371","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0009-0002-5774-0838","authenticated-orcid":true,"given":"Yuuka","family":"Yasuura","sequence":"first","affiliation":[{"name":"Graduate School of Health Sciences, Kio University","place":["Nara, Japan"]},{"name":"Shimada Hospital","place":["Osaka, Japan"],"department":["Department of Rehabilitation"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7416-0881","authenticated-orcid":true,"given":"Takahiko","family":"Fukumoto","sequence":"additional","affiliation":[{"name":"Graduate School of Health Sciences, Kio University","place":["Nara, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hiroaki","family":"Yamano","sequence":"additional","affiliation":[{"name":"Graduate School of Health Sciences, Kio University","place":["Nara, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuya","family":"Mawarikado","sequence":"additional","affiliation":[{"name":"Graduate School of Medicine, Musculoskeletal Reconstructive Surgery, Nara Medical University","place":["Nara, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1009-1412","authenticated-orcid":true,"given":"Daisuke","family":"Uritani","sequence":"additional","affiliation":[{"name":"Graduate School of Health Sciences, Kio University","place":["Nara, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2026,9,8]]},"reference":[{"issue":"6","key":"pone.0357407.ref001","doi-asserted-by":"crossref","first-page":"518","DOI":"10.1177\/1941738117714160","article-title":"Association of Competition Volume, Club Sports, and Sport Specialization With Sex and Lower Extremity Injury History in High School Athletes","volume":"9","author":"EG Post","year":"2017","journal-title":"Sports Health"},{"issue":"6","key":"pone.0357407.ref002","doi-asserted-by":"crossref","first-page":"1405","DOI":"10.1177\/0363546517690848","article-title":"The Association of Sport Specialization and Training Volume With Injury History in Youth Athletes","volume":"45","author":"EG Post","year":"2017","journal-title":"Am J Sports Med"},{"issue":"4","key":"pone.0357407.ref003","doi-asserted-by":"crossref","first-page":"545","DOI":"10.1007\/s40279-015-0438-0","article-title":"At What Age Do Children and Adolescents Develop Lower Limb Tendon Pathology or Tendinopathy? A Systematic Review and Meta-analysis","volume":"46","author":"M Simpson","year":"2016","journal-title":"Sports Med"},{"key":"pone.0357407.ref004","doi-asserted-by":"crossref","DOI":"10.1136\/bmjopen-2018-024113","article-title":"Five-year prognosis and impact of adolescent knee pain: a prospective population-based cohort study of 504 adolescents in Denmark","volume":"9","author":"MS Rathleff","year":"2019","journal-title":"BMJ Open"},{"issue":"1","key":"pone.0357407.ref005","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1016\/j.arthro.2023.09.004","article-title":"Management of Patellar Tendinopathy","volume":"40","author":"JW Arner","year":"2024","journal-title":"Arthroscopy"},{"issue":"9","key":"pone.0357407.ref006","doi-asserted-by":"crossref","first-page":"1277","DOI":"10.1007\/s00402-015-2270-2","article-title":"Precise risk factors for Osgood-Schlatter disease","volume":"135","author":"J Nakase","year":"2015","journal-title":"Arch Orthop Trauma Surg"},{"issue":"9","key":"pone.0357407.ref007","doi-asserted-by":"crossref","first-page":"23259671231202209","DOI":"10.1177\/23259671231202209","article-title":"Analysis of Quadriceps Muscle Tightness as a Risk Factor for Osgood-Schlatter Disease: A Prospective Cohort Study","volume":"11","author":"Y Murayama","year":"2023","journal-title":"Orthop J Sports Med"},{"issue":"1","key":"pone.0357407.ref008","doi-asserted-by":"crossref","first-page":"107","DOI":"10.1097\/MOP.0000000000000842","article-title":"Osgood-Schlatter disease: a 2020 update of a common knee condition in children","volume":"32","author":"HN Ladenhauf","year":"2020","journal-title":"Curr Opin Pediatr"},{"issue":"5","key":"pone.0357407.ref009","doi-asserted-by":"crossref","first-page":"468","DOI":"10.1097\/JSM.0000000000000397","article-title":"Patellar Tendinopathy and Potential Risk Factors: An International Database of Cases and Controls","volume":"27","author":"S Morton","year":"2017","journal-title":"Clin J Sport Med"},{"issue":"6","key":"pone.0357407.ref010","first-page":"826","article-title":"The Etiology and Risk Factors of Osgood-Schlatter Disease: A Systematic Review","volume":"9","author":"L Lucenti","year":"2022","journal-title":"Children (Basel)"},{"key":"pone.0357407.ref011","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1016\/j.ptsp.2015.12.001","article-title":"Lower limb strength and flexibility in athletes with and without patellar tendinopathy","volume":"20","author":"R Scattone Silva","year":"2016","journal-title":"Phys Ther Sport"},{"key":"pone.0357407.ref012","doi-asserted-by":"crossref","first-page":"39","DOI":"10.1016\/j.jor.2025.11.015","article-title":"A retrospective study comparing ultrasound and MRI for diagnosing quadriceps and patellar tendon ruptures, along with a cost-benefit analysis of these imaging techniques","volume":"72","author":"HA Crouch-Smith","year":"2025","journal-title":"J Orthop"},{"issue":"2","key":"pone.0357407.ref013","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1136\/bjsports-2012-091303","article-title":"The prevalence and clinical significance of sonographic tendon abnormalities in asymptomatic ballet dancers: a 24-month longitudinal study","volume":"47","author":"J Comin","year":"2013","journal-title":"Br J Sports Med"},{"issue":"12","key":"pone.0357407.ref014","doi-asserted-by":"crossref","first-page":"1280","DOI":"10.4085\/1062-6050-285-17","article-title":"Lower Limb Dominance, Morphology, and Sonographic Abnormalities of the Patellar Tendon in Elite Basketball Players: A Cross-Sectional Study","volume":"54","author":"JC Ben\u00edtez-Mart\u00ednez","year":"2019","journal-title":"J Athl Train"},{"issue":"4","key":"pone.0357407.ref015","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1007\/s001670000189","article-title":"Neovascularisation in Achilles tendons with painful tendinosis but not in normal tendons: an ultrasonographic investigation","volume":"9","author":"L Ohberg","year":"2001","journal-title":"Knee Surg Sports Traumatol Arthrosc"},{"issue":"9","key":"pone.0357407.ref016","doi-asserted-by":"crossref","first-page":"726","DOI":"10.1055\/a-0633-9098","article-title":"Incidence of Achilles and Patellar Tendinopathy in Adolescent Elite Athletes","volume":"39","author":"M Cassel","year":"2018","journal-title":"Int J Sports Med"},{"issue":"4","key":"pone.0357407.ref017","doi-asserted-by":"crossref","first-page":"471","DOI":"10.1111\/j.1469-7580.2006.00540.x","article-title":"Where tendons and ligaments meet bone: attachment sites (\u2018entheses\u2019) in relation to exercise and\/or mechanical load","volume":"208","author":"M Benjamin","year":"2006","journal-title":"J Anat"},{"issue":"7","key":"pone.0357407.ref018","doi-asserted-by":"crossref","first-page":"621","DOI":"10.4085\/1062-6050-0049.21","article-title":"Clinical Management of Patellar Tendinopathy","volume":"57","author":"AB Rosen","year":"2022","journal-title":"J Athl Train"},{"key":"pone.0357407.ref019","doi-asserted-by":"crossref","first-page":"254","DOI":"10.1016\/j.ptsp.2020.10.002","article-title":"Evaluation of patellar tendinopathy using the single leg decline squat test: Is pain location important?","volume":"46","author":"BK Coombes","year":"2020","journal-title":"Phys Ther Sport"},{"issue":"24","key":"pone.0357407.ref020","doi-asserted-by":"crossref","first-page":"2714","DOI":"10.1097\/00007632-200112150-00018","article-title":"Reliability of the lumbar flexion, lumbar extension, and passive straight leg raise test in normal populations embedded within a complete physical examination","volume":"26","author":"DG Hunt","year":"2001","journal-title":"Spine (Phila Pa 1976)"},{"issue":"5","key":"pone.0357407.ref021","doi-asserted-by":"crossref","DOI":"10.1177\/2325967119847978","article-title":"Relationship Between Lower Limb Tightness and Practice Time Among Adolescent Baseball Players With Symptomatic Osgood-Schlatter Disease","volume":"7","author":"T Omodaka","year":"2019","journal-title":"Orthop J Sports Med"},{"issue":"9","key":"pone.0357407.ref022","doi-asserted-by":"crossref","first-page":"1164","DOI":"10.1002\/jor.20415","article-title":"Clinical features of patellar tendinopathy and their implications for rehabilitation","volume":"25","author":"KM Crossley","year":"2007","journal-title":"J Orthop Res"},{"issue":"5","key":"pone.0357407.ref023","doi-asserted-by":"crossref","first-page":"472","DOI":"10.1016\/j.pmrj.2010.10.025","article-title":"Hand-held dynamometry correlation with the gold standard isokinetic dynamometry: a systematic review","volume":"3","author":"T Stark","year":"2011","journal-title":"PM R"},{"issue":"6","key":"pone.0357407.ref024","doi-asserted-by":"crossref","first-page":"1799","DOI":"10.1589\/jpts.27.1799","article-title":"The intra- and inter-rater reliabilities of lower extremity muscle strength assessment of healthy adults using a hand held dynamometer","volume":"27","author":"S-G Kim","year":"2015","journal-title":"J Phys Ther Sci"},{"issue":"4","key":"pone.0357407.ref025","doi-asserted-by":"crossref","DOI":"10.1519\/JPT.0000000000000207","article-title":"Reliability and Validity of Seated Hip Extensor Strength Measurement by Handheld Dynamometer in Older Adults","volume":"42","author":"T Seko","year":"2019","journal-title":"J Geriatr Phys Ther"},{"issue":"10","key":"pone.0357407.ref026","doi-asserted-by":"crossref","DOI":"10.1371\/journal.pone.0140822","article-title":"Assessment of Lower Limb Muscle Strength and Power Using Hand-Held and Fixed Dynamometry: A Reliability and Validity Study","volume":"10","author":"BF Mentiplay","year":"2015","journal-title":"PLoS One"},{"key":"pone.0357407.ref027","doi-asserted-by":"crossref","first-page":"4092","DOI":"10.3390\/jcm10184092","article-title":"An objective measure of patellar tendon thickness based on ultrasonography and MRI in university athletes","volume":"10","author":"Y Nishida","year":"2021","journal-title":"J Clin Med"},{"issue":"3","key":"pone.0357407.ref028","doi-asserted-by":"crossref","first-page":"451","DOI":"10.1177\/0363546507310073","article-title":"Prophylactic training in asymptomatic soccer players with ultrasonographic abnormalities in Achilles and patellar tendons: the Danish Super League Study","volume":"36","author":"U Fredberg","year":"2008","journal-title":"Am J Sports Med"},{"key":"pone.0357407.ref029","first-page":"2331","article-title":"Osgood-Schlatter disease: what is it and how is it treated?","volume":"66","author":"W Hennrikus","year":"2002","journal-title":"Am Fam Physician"},{"issue":"9","key":"pone.0357407.ref030","doi-asserted-by":"crossref","first-page":"1984","DOI":"10.1177\/0363546511413370","article-title":"Prevalence of Jumper\u2019s knee among nonelite athletes from different sports: a cross-sectional survey","volume":"39","author":"J Zwerver","year":"2011","journal-title":"Am J Sports Med"},{"issue":"4","key":"pone.0357407.ref031","doi-asserted-by":"crossref","first-page":"561","DOI":"10.1177\/0363546504270454","article-title":"Prevalence of jumper\u2019s knee among elite athletes from different sports: a cross-sectional study","volume":"33","author":"OB Lian","year":"2005","journal-title":"Am J Sports Med"},{"key":"pone.0357407.ref032","volume-title":"Utilizing rehabilitation: A clear guide to musculoskeletal ultrasound","author":"T Kotake","year":"2019"},{"issue":"2","key":"pone.0357407.ref033","doi-asserted-by":"crossref","first-page":"157","DOI":"10.1177\/1941738118820517","article-title":"Patellar and Achilles Tendon Stiffness in Elite Soccer Players Assessed Using Myotonometric Measurements","volume":"11","author":"I Cristi-S\u00e1nchez","year":"2019","journal-title":"Sports Health"},{"issue":"6","key":"pone.0357407.ref034","doi-asserted-by":"crossref","first-page":"409","DOI":"10.1136\/bjsm.2008.051193","article-title":"Is tendon pathology a continuum? A pathology model to explain the clinical presentation of load-induced tendinopathy","volume":"43","author":"JL Cook","year":"2009","journal-title":"Br J Sports Med"},{"issue":"19","key":"pone.0357407.ref035","doi-asserted-by":"crossref","first-page":"1187","DOI":"10.1136\/bjsports-2015-095422","article-title":"Revisiting the continuum model of tendon pathology: what is its merit in clinical practice and research?","volume":"50","author":"JL Cook","year":"2016","journal-title":"Br J Sports Med"},{"issue":"10","key":"pone.0357407.ref036","article-title":"Clinical Outcomes and Tendon Structure at 3- to 4-Year Follow-up After Exercise-Based Treatment of Patellar Tendinopathy: A Prospective Study","volume":"12","author":"A-S Agergaard","year":"2024","journal-title":"Orthop J Sports Med"},{"key":"pone.0357407.ref037","doi-asserted-by":"crossref","unstructured":"Lee W, Zhang Z, Ying T, Ng Y, Fu S. 53\u2005Correlation between vascularity with power Doppler ultrasonography assessment and pain in patients with patellar tendinopathy. In: Abstracts. BMJ Publishing Group Ltd. and British Association of Sport and Exercise Medicine; 2014:A34.2\u2013A3A35. https:\/\/doi.org\/10.1136\/bjsports-2014-094114.53","DOI":"10.1136\/bjsports-2014-094114.53"},{"issue":"13","key":"pone.0357407.ref038","doi-asserted-by":"crossref","first-page":"944","DOI":"10.1136\/bjsm.2008.054916","article-title":"Temporal sequence of greyscale ultrasound changes and their relationship with neovascularity and pain in the patellar tendon","volume":"44","author":"P Malliaras","year":"2010","journal-title":"Br J Sports Med"},{"issue":"10","key":"pone.0357407.ref039","doi-asserted-by":"crossref","first-page":"808","DOI":"10.1002\/jemt.20351","article-title":"Immunohistochemical and histochemical findings favoring the occurrence of autocrine\/paracrine as well as nerve-related cholinergic effects in chronic painful patellar tendon tendinosis","volume":"69","author":"P Danielson","year":"2006","journal-title":"Microsc Res Tech"},{"issue":"13","key":"pone.0357407.ref040","doi-asserted-by":"crossref","first-page":"1048","DOI":"10.1136\/bjsm.2010.082180","article-title":"Changes in anteroposterior patellar tendon diameter support a continuum of pathological changes","volume":"45","author":"P Malliaras","year":"2011","journal-title":"Br J Sports Med"},{"key":"pone.0357407.ref041","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1016\/j.ptsp.2023.02.009","article-title":"Self-reported bio-psycho-social factors partially distinguish patellar tendinopathy from other knee problems and explain patellar tendinopathy severity in jumping athletes: A case-control study","volume":"61","author":"A Tayfur","year":"2023","journal-title":"Phys Ther Sport"},{"issue":"1","key":"pone.0357407.ref042","doi-asserted-by":"crossref","first-page":"123","DOI":"10.1007\/s40279-021-01550-6","article-title":"Are Landing Patterns in Jumping Athletes Associated with Patellar Tendinopathy? A Systematic Review with Evidence Gap Map and Meta-analysis","volume":"52","author":"A Tayfur","year":"2022","journal-title":"Sports Med"},{"issue":"3","key":"pone.0357407.ref043","doi-asserted-by":"crossref","first-page":"805","DOI":"10.1152\/japplphysiol.90361.2008","article-title":"Habitual loading results in tendon hypertrophy and increased stiffness of the human patellar tendon","volume":"105","author":"C Coupp\u00e9","year":"2008","journal-title":"J Appl Physiol (1985)"}],"container-title":["PLOS One"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0357407","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T17:33:15Z","timestamp":1788888795000},"score":1,"resource":{"primary":{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0357407"}},"subtitle":[],"editor":[{"given":"Zulkarnain","family":"Jaafar","sequence":"first","affiliation":[{"name":"Universiti Malaya","place":["MALAYSIA"]}],"role":[{"vocabulary":"crossref","role":"editor"}]}],"short-title":[],"issued":{"date-parts":[[2026,9,8]]},"references-count":43,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2026,9,8]]}},"URL":"https:\/\/doi.org\/10.1371\/journal.pone.0357407","relation":{},"ISSN":["1932-6203"],"issn-type":[{"value":"1932-6203","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,8]]}}}