{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,5]],"date-time":"2026-01-05T10:33:55Z","timestamp":1767609235808,"version":"3.48.0"},"reference-count":50,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2026,1,5]],"date-time":"2026-01-05T00:00:00Z","timestamp":1767571200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>Background\/Objectives: Proximal hamstring injuries involving the biceps femoris\u2013semitendinosus (BF\u2013ST) conjoint tendon (CT) often exhibit delayed healing, yet the prognostic significance of CT involvement and intratendinous injury morphology has not been fully clarified. This study aimed to determine whether full-layer CT injury, particularly bilateral involvement in Zone C, prolongs return-to-play (RTP) in competitive rugby athletes. Methods: This prospective study evaluated 41 university rugby players with acute BF\u2013ST complex injuries using clinical examination, ultrasonography, and MRI. Injuries were classified by Type (I: full-layer CT; II: BFLH-only; III: ST-only), Zone (A\u2013E), and Grade (0\u20133). RTP was defined as unrestricted return to team training or match play. Group differences were analyzed using ANOVA or non-parametric tests with appropriate post hoc corrections. Results: Type I injuries required significantly longer RTP (11.4 \u00b1 4.8 weeks) than Type II (5.3 \u00b1 2.4 weeks) and Type III (4.0 \u00b1 1.7 weeks), confirming the strong impact of CT involvement on prognosis. In Zone C, bilateral full-layer CT involvement was associated with an approximately twofold longer RTP duration compared with unilateral BFLH-side injuries, indicating that intratendinous tissue disruption influences recovery. These findings highlight the importance of early MRI-based assessment to identify clinically relevant tendon involvement patterns. Conclusions: Full-layer CT injuries, particularly bilateral intratendinous patterns in Zone C, markedly prolong RTP compared with isolated BFLH or ST injuries. An MRI-based classification incorporating injury type, zone, and extent of CT involvement provides clinically valuable prognostic information and may enhance RTP decision-making.<\/jats:p>","DOI":"10.3390\/diagnostics16010166","type":"journal-article","created":{"date-parts":[[2026,1,5]],"date-time":"2026-01-05T10:03:48Z","timestamp":1767607428000},"page":"166","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Impact of Proximal Conjoint Tendon Injury on Return to Play in the BF\u2013ST Complex: A Prospective MRI-Based Study"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3329-4135","authenticated-orcid":false,"given":"Makoto","family":"Wada","sequence":"first","affiliation":[{"name":"Department of Orthopedic Surgery, Wada Orthopedic Clinic, Osaka 573-0163, Japan"},{"name":"Waseda Institute for Sport Sciences, Saitama 359-1192, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7801-9815","authenticated-orcid":false,"given":"Takumi","family":"Okunuki","sequence":"additional","affiliation":[{"name":"Graduate School of Sport Sciences, Waseda University, Saitama 359-1192, Japan"},{"name":"Research Organization of Science and Technology, Ritsumeikan University, Shiga 525-8577, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5949-0599","authenticated-orcid":false,"given":"Takeshi","family":"Sugimoto","sequence":"additional","affiliation":[{"name":"Department of Orthopedic Surgery, Osaka Global Orthopedic Hospital, Osaka 536-0008, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2300-611X","authenticated-orcid":false,"given":"Yasuhito","family":"Tanaka","sequence":"additional","affiliation":[{"name":"Department of Orthopedic Surgery, Nara Medical University, Nara 634-8521, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3738-9171","authenticated-orcid":false,"given":"Tsukasa","family":"Kumai","sequence":"additional","affiliation":[{"name":"Faculty of Sport Sciences, Waseda University, Saitama 359-1192, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,1,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"21","DOI":"10.2165\/00007256-198502010-00003","article-title":"Hamstring Injuries","volume":"2","author":"Agre","year":"1985","journal-title":"Sports Med."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"2933","DOI":"10.1177\/0363546513487063","article-title":"Evaluation and Management of Hamstring Injuries","volume":"41","author":"Ahmad","year":"2013","journal-title":"Am. J. Sports Med."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"731","DOI":"10.1136\/bjsports-2015-095359","article-title":"Hamstring Injuries Have Increased by 4% Annually in Men\u2019s Professional Football, since 2001: A 13-Year Longitudinal Analysis of the UEFA Elite Club Injury Study","volume":"50","author":"Ekstrand","year":"2016","journal-title":"Br. J. Sports Med."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"237","DOI":"10.1136\/jisakos-2019-000420","article-title":"Proximal Hamstring Tendon Avulsion: State of the Art","volume":"6","author":"Bertiche","year":"2021","journal-title":"J. ISAKOS"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"244","DOI":"10.1034\/j.1600-0838.2003.00312.x","article-title":"Hamstring Injury Occurrence in Elite Soccer Players after Preseason Strength Training with Eccentric Overload","volume":"13","author":"Askling","year":"2003","journal-title":"Scand. Med. Sci. Sports"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"209","DOI":"10.2165\/11594800-000000000-00000","article-title":"Hamstring Strain Injuries","volume":"42","author":"Opar","year":"2012","journal-title":"Sports Med."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1081","DOI":"10.1136\/bjsports-2019-100983","article-title":"Recalibrating the Risk of Hamstring Strain Injury (HSI): A 2020 Systematic Review and Meta-Analysis of Risk Factors for Index and Recurrent Hamstring Strain Injury in Sport","volume":"54","author":"Green","year":"2020","journal-title":"Br. J. Sports Med."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"292","DOI":"10.1136\/bjsports-2021-105407","article-title":"Hamstring Injury Rates Have Increased during Recent Seasons and Now Constitute 24% of All Injuries in Men\u2019s Professional Football: The UEFA Elite Club Injury Study from 2001\/02 to 2021\/22","volume":"57","author":"Ekstrand","year":"2023","journal-title":"Br. J. Sports Med."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1316","DOI":"10.1177\/0363546515574057","article-title":"The preventive effect of the nordic hamstring exercise on hamstring injuries in amateur soccer players: A randomized controlled trial","volume":"43","author":"Smits","year":"2015","journal-title":"Am. J. Sports Med."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"351","DOI":"10.1136\/bjsports-2011-090664","article-title":"Risk factors for hamstring muscle strain injury in sport: A systematic review and meta-analysis","volume":"47","author":"Freckleton","year":"2013","journal-title":"Br. J. Sports Med."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"23259671211053833","DOI":"10.1177\/23259671211053833","article-title":"Evidence-Based Management and Factors Associated with Return to Play After Acute Hamstring Injury in Athletes: A Systematic Review","volume":"9","author":"Rudisill","year":"2021","journal-title":"Orthop. J. Sports Med."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"197","DOI":"10.1177\/0363546506294679","article-title":"Acute First-Time Hamstring Strains during High-Speed Running: A Longitudinal Study Including Clinical and Magnetic Resonance Imaging Findings","volume":"35","author":"Askling","year":"2007","journal-title":"Am. J. Sports Med."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"296","DOI":"10.1249\/JSR.0000000000000516","article-title":"Return to Play After Thigh Muscle Injury: Utility of Serial Ultrasound in Guiding Clinical Progression","volume":"17","author":"Hall","year":"2018","journal-title":"Curr. Sports Med. Rep."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1177\/0363546512463679","article-title":"Return to Competitive Play After Hamstring Injuries Involving Disruption of the Central Tendon","volume":"41","author":"Comin","year":"2013","journal-title":"Am. J. Sports Med."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"E94","DOI":"10.1055\/s-0043-111587","article-title":"Semimembranosus Muscle Injuries In Sport. A Practical MRI Use for Prognosis","volume":"1","author":"Balius","year":"2017","journal-title":"Sports Med. Int. Open"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"131","DOI":"10.1055\/s-0030-1253157","article-title":"Hamstring injuries: Anatomy, imaging, and intervention","volume":"14","author":"Linklater","year":"2010","journal-title":"Semin. Musculoskelet. Radiol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"3772","DOI":"10.1016\/j.ejrad.2011.03.099","article-title":"The Proximal Hamstring Muscle\u2013Tendon\u2013Bone Unit: A Review of the Normal Anatomy, Biomechanics, and Pathophysiology","volume":"81","author":"Beltran","year":"2012","journal-title":"Eur. J. Radiol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"44","DOI":"10.2106\/JBJS.F.00094","article-title":"The Proximal Origin of the Hamstrings and Surrounding Anatomy Encountered During Repair: A Cadaveric Study","volume":"89","author":"Miller","year":"2007","journal-title":"J. Bone Jt. Surg."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"2576","DOI":"10.1007\/s00167-014-3124-0","article-title":"Gross Anatomical and Dimensional Characteristics of the Proximal Hamstring Origin","volume":"23","author":"Feucht","year":"2015","journal-title":"Knee Surg. Sports Traumatol. Arthrosc."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Miguel-P\u00e9rez, M., Iglesias-Chamorro, P., Ortiz-Miguel, S., Ortiz-Sagrist\u00e0, J.-C., M\u00f6ller, I., Blasi, J., Agull\u00f2, J., Martinoli, C., and P\u00e9rez-Bellmunt, A. (2024). Anatomical Relationships of the Proximal Attachment of the Hamstring Muscles with Neighboring Structures: From Ultrasound, Anatomical and Histological Findings to Clinical Implications. Diagnostics, 14.","DOI":"10.3390\/diagnostics14161725"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1313","DOI":"10.1080\/02640414.2017.1375548","article-title":"Differences in Hamstring Activation Characteristics between the Acceleration and Maximum-Speed Phases of Sprinting","volume":"36","author":"Higashihara","year":"2018","journal-title":"J. Sports Sci."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"647","DOI":"10.1249\/MSS.0b013e318236a3d2","article-title":"Mechanics of the Human Hamstring Muscles during Sprinting","volume":"44","author":"Schache","year":"2012","journal-title":"Med. Sci. Sports Exerc."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"42","DOI":"10.1080\/15438627.2011.535769","article-title":"Hamstring Functions During Hip-Extension Exercise Assessed with Electromyography and Magnetic Resonance Imaging","volume":"19","author":"Ono","year":"2010","journal-title":"Res. Sports Med."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"e653","DOI":"10.1016\/j.asmr.2021.12.007","article-title":"Acute Proximal Hamstring Tears Can Be Defined Using an Imaged-Based Classification","volume":"4","author":"Forlizzi","year":"2022","journal-title":"Arthrosc. Sports Med. Rehabil."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"525","DOI":"10.2214\/AJR.12.8784","article-title":"Imaging Diagnosis and Prognostication of Hamstring Injuries","volume":"199","author":"Rubin","year":"2012","journal-title":"Am. J. Roentgenol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"50","DOI":"10.1016\/j.jcot.2020.08.021","article-title":"Hamstring Origin\u2013Anatomy, Angle of Origin and Its Possible Clinical Implications","volume":"13","author":"Azzopardi","year":"2021","journal-title":"J. Clin. Orthop. Trauma"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"646","DOI":"10.1148\/radiol.2017160267","article-title":"Imaging of Muscle Injuries in Sports Medicine: Sports Imaging Series","volume":"282","author":"Guermazi","year":"2017","journal-title":"Radiology"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1370","DOI":"10.1136\/bjsports-2013-092450","article-title":"MRI observations at return to play of clinically recovered hamstring injuries","volume":"48","author":"Reurink","year":"2014","journal-title":"Br. J. Sports Med."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Wada, M., Kumai, T., Okunuki, T., Sugimoto, T., Ishizuka, K., and Tanaka, Y. (2025). Ultrasound Diagnosis of Hamstring Muscle Complex Injuries: Focus on Originate Tendon Structure\u2014Male University Rugby Players. Diagnostics, 15.","DOI":"10.3390\/diagnostics15010054"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"342","DOI":"10.1136\/bjsports-2012-091448","article-title":"Terminology and Classification of Muscle Injuries in Sport: The Munich Consensus Statement","volume":"47","author":"Haensel","year":"2013","journal-title":"Br. J. Sports Med."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"46","DOI":"10.1016\/j.jsams.2024.07.016","article-title":"Classification of myo-connective tissue injuries for severity grading and return to play prediction: A scoping review","volume":"28","author":"Fontanier","year":"2025","journal-title":"J. Sci. Med. Sport"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1347","DOI":"10.1136\/bjsports-2013-093302","article-title":"British Athletics Muscle Injury Classification: A New Grading System","volume":"48","author":"Pollock","year":"2014","journal-title":"Br. J. Sports Med."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Lutz, P.M., Kn\u00f6rr, M., Geyer, S., Imhoff, A.B., and Feucht, M.J. (2021). Delayed Proximal Hamstring Tendon Repair after Ischial Tuberosity Apophyseal Fracture in a Professional Volleyball Athlete: A Case Report. BMC Musculoskelet. Disord., 22.","DOI":"10.1186\/s12891-021-04468-2"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"4139","DOI":"10.1007\/s00590-024-04096-1","article-title":"Proximal Avulsion of the Hamstring in Young Athlete Patients: A Case Series and Review of Literature","volume":"34","author":"Castelli","year":"2024","journal-title":"Eur. J. Orthop. Surg. Traumatol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"785","DOI":"10.1177\/03635465980260060801","article-title":"Surgical Repair of Chronic Complete Hamstring Tendon Rupture in the Adult Patient","volume":"26","author":"Cross","year":"1998","journal-title":"Am. J. Sports Med."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"257","DOI":"10.1136\/bjsports-2020-103791","article-title":"A 4-Year Study of Hamstring Injury Outcomes in Elite Track and Field Using the British Athletics Rehabilitation Approach","volume":"56","author":"Pollock","year":"2022","journal-title":"Br. J. Sports Med."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"211","DOI":"10.1055\/s-0030-1268011","article-title":"An anatomical study of the proximal hamstring muscle complex to elucidate muscle strains in this region","volume":"32","author":"Battermann","year":"2011","journal-title":"Int. J. Sports Med."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1341","DOI":"10.4067\/S0717-95022020000501341","article-title":"Common Origin Tendon of the Biceps Femoris and Semitendinosus Muscles, Functional and Clinical Relevance","volume":"38","year":"2020","journal-title":"Int. J. Morphol."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"2325967115625055","DOI":"10.1177\/2325967115625055","article-title":"Anatomy of the Adductor Magnus Origin: Implications for Proximal Hamstring Injuries","volume":"4","author":"Obey","year":"2016","journal-title":"Orthop. J. Sports Med."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1159\/000085004","article-title":"Hamstring Muscles: Architecture and Innervation","volume":"179","author":"Woodley","year":"2005","journal-title":"Cells Tissues Organs"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1080\/02640414.2010.494308","article-title":"Functional differences in the activity of the hamstring muscles during sprinting","volume":"28","author":"Higashihara","year":"2010","journal-title":"J. Sports Sci."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"3555","DOI":"10.1016\/j.jbiomech.2007.05.026","article-title":"The Effect of Speed and Influence of Individual Muscles on Hamstring Mechanics during the Swing Phase of Sprinting","volume":"40","author":"Chumanov","year":"2007","journal-title":"J. Biomech."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"75","DOI":"10.1186\/s40798-023-00621-4","article-title":"Intramuscular Tendon Injuries of the Hamstring Muscles: A More Severe Variant?","volume":"9","author":"Kerin","year":"2023","journal-title":"Sports Med. Open"},{"key":"ref_44","first-page":"83","article-title":"Intramuscular tendon involvement on MRI has limited value for predicting time to return to play following acute hamstring injury","volume":"52","author":"Almusa","year":"2017","journal-title":"Br. J. Sports Med."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"2325967118795863","DOI":"10.1177\/2325967118795863","article-title":"Role of the Extracellular Matrix in Muscle Injuries: Histoarchitectural Considerations for Muscle Injuries","volume":"6","author":"Balius","year":"2018","journal-title":"Orthop. J. Sports Med."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"2325967120909090","DOI":"10.1177\/2325967120909090","article-title":"A histoarchitectural approach to skeletal muscle injury: Searching for a common nomenclature","volume":"8","author":"Balius","year":"2020","journal-title":"Orthop. J. Sports Med."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"649","DOI":"10.1152\/physrev.00031.2003","article-title":"Role of Extracellular Matrix in Adaptation of Tendon and Skeletal Muscle to Mechanical Loading","volume":"84","year":"2004","journal-title":"Physiol. Rev."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"78","DOI":"10.2478\/acb-2023-0013","article-title":"Hamstring tendon muscle injuries\u2014Anatomy, mechanisms and rehabilitation","volume":"11","author":"Barzak","year":"2023","journal-title":"Med. J. Cell Biol."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"1799","DOI":"10.1177\/0363546508315892","article-title":"Proximal Hamstring Strains of Stretching Type in Different Sports: Injury Situations, Clinical and Magnetic Resonance Imaging Characteristics, and Return to Sport","volume":"36","author":"Askling","year":"2008","journal-title":"Am. J. Sports Med."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"125","DOI":"10.4085\/1062-6050-0707.20","article-title":"Hamstring Strain Injury Rehabilitation","volume":"57","author":"Hickey","year":"2021","journal-title":"J. Athl. Train."}],"container-title":["Diagnostics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/1\/166\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,1,5]],"date-time":"2026-01-05T10:17:36Z","timestamp":1767608256000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/1\/166"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,1,5]]},"references-count":50,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2026,1]]}},"alternative-id":["diagnostics16010166"],"URL":"https:\/\/doi.org\/10.3390\/diagnostics16010166","relation":{},"ISSN":["2075-4418"],"issn-type":[{"value":"2075-4418","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,1,5]]}}}