[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"health-study-detail:100620763":3},{"organization":4,"armGroups":7,"interventions":20,"overallOfficials":33,"centralContacts":34,"locations":41,"responsibleParty":78,"collaborators":33,"id":81,"slug":82,"hasResults":83,"nctId":84,"briefTitle":85,"officialTitle":86,"acronym":87,"eligibilityCriteria":88,"healthyVolunteers":83,"sex":89,"minAge":90,"maxAge":91,"enrollmentInfo":92,"targetDuration":33,"studyType":95,"phases":96,"briefSummary":98,"conditions":99,"keywords":101,"overallStatus":125,"whyStopped":33,"lastUpdateSubmitDate":126,"lastUpdatePostDateStruct":127,"startDateStruct":130,"completionDateStruct":132,"leadSponsor":134,"locationsCount":135},{"fullName":5,"class":6},"Universidad Complutense de Madrid","OTHER",[8,14],{"label":9,"type":10,"description":11,"interventionNames":12},"Long-Hold Yielding Isometrics","EXPERIMENTAL","This arm receives a structured long-hold yielding isometric (LH-YI) exercise program targeting the patellar tendon. Participants perform 3-5 sets of 3-5 repetitions, each consisting of a 30-60 second sustained isometric contraction at a discomfort level of 3-4\u002F10. Exercises are performed three times per week for 8 weeks, using a yielding squat or mid-range knee-flexion isometric position. Load is individualized based on tolerance. One supervised session per week ensures correct technique and monitoring. The protocol aims to improve pain, tendon vascularity, stiffness, and neuromechanical performance through prolonged tendon loading.",[13],"Behavioral: Long-Hold Yielding Isometric Exercise Program",{"label":15,"type":16,"description":17,"interventionNames":18},"Usual-Care Training Condition","ACTIVE_COMPARATOR","This arm follows standard training recommendations for patellar tendinopathy without exposure to long-duration isometric loading. Participants maintain their regular weightlifting training with guidance on load management, symptom monitoring, and progressive strengthening. No sustained isometric exercises are permitted. This condition serves as a real-world comparable control to evaluate the specific effects of long-hold yielding isometrics on pain, function, tendon vascularity, stiffness, and neuromechanical performance.",[19],"Other: Usual-Care Training Condition",[21,28],{"type":22,"name":23,"description":24,"armGroupLabels":25,"otherNames":26},"BEHAVIORAL","Long-Hold Yielding Isometric Exercise Program","The intervention consists of a structured long-hold yielding isometric (LH-YI) loading program targeting the patellar tendon. Participants perform 3-5 sets of 3-5 repetitions, each held for 30-60 seconds at an intensity corresponding to 3-4\u002F10 discomfort. Exercises are executed in a controlled knee-flexion position, either as a yielding squat or machine-assisted isometric hold. Training takes place three times per week for 8 weeks, with one supervised session weekly to ensure correct load, technique, adherence, and safety. The protocol aims to induce mechanotransductive adaptation, reduce pain, modulate tendon vascularity, and improve tendon stiffness and neuromechanical performance.",[9],[27],"Long-Hold Isometric Loading",{"type":6,"name":15,"description":29,"armGroupLabels":30,"otherNames":31},"Participants maintain their regular weightlifting training following standard recommendations for patellar tendinopathy management. This includes load monitoring, symptom-guided progression, avoidance of high-irritability movements, and general strengthening. No long-duration isometric exercises or targeted LH-YI loading are permitted. This condition serves as an active comparator reflecting real-world practice to isolate the specific therapeutic and mechanobiological effects of the long-hold yielding isometric protocol.",[15],[32],"Standard Tendinopathy Management",null,[35],{"name":36,"role":37,"phone":38,"phoneExt":39,"email":40},"Jaime Almazán Polo, Doctor","CONTACT","34 + 652103445","34","jaalmaza@ucm.es",[42],{"facility":43,"status":33,"city":44,"state":44,"zip":45,"country":46,"countryCode":47,"cosmosGeoPoint":48,"geoPoint":53,"contacts":54},"Universidad Complutense de Madrid, Faculty of Nursing, Physiotherapy and Podiatry, Department of Physiotherapy","Madrid","28040","Spain","ES",{"type":49,"coordinates":50},"Point",[51,52],-3.70256,40.4165,{"lat":52,"lon":51},[55,57,61,64,66,68,70,72,74,76],{"name":36,"role":37,"phone":56,"phoneExt":39,"email":40},"652103445",{"name":58,"role":37,"phone":59,"phoneExt":39,"email":60},"César Calvo Lobo, Doctor","605811782","cescalvo@ucm.es",{"name":62,"role":63,"phone":33,"phoneExt":33,"email":33},"Cesar Calvo Lobo, Doctor","SUB_INVESTIGATOR",{"name":36,"role":65,"phone":33,"phoneExt":33,"email":33},"PRINCIPAL_INVESTIGATOR",{"name":67,"role":63,"phone":33,"phoneExt":33,"email":33},"Ricardo Becerro de Bengoa Vallejo, Doctor",{"name":69,"role":63,"phone":33,"phoneExt":33,"email":33},"José López Chicharro, Doctor",{"name":71,"role":63,"phone":33,"phoneExt":33,"email":33},"Ángel González de la Flor, Doctor",{"name":73,"role":63,"phone":33,"phoneExt":33,"email":33},"David Rodriguez Sanz, Doctor",{"name":75,"role":63,"phone":33,"phoneExt":33,"email":33},"Marcos Antonio Soriano Rodriguez, Doctor",{"name":77,"role":63,"phone":33,"phoneExt":33,"email":33},"Davinia Vicente Campos, Doctor",{"type":65,"investigatorFullName":79,"investigatorTitle":80,"investigatorAffiliation":5,"oldNameTitle":33,"oldOrganization":33},"Jaime Almazán Polo","Assistant Professor of Physiotherapy and Principal Investigator","100620763","long-hold-yielding-isometric-exercise-for-patellar-tendinopathy-in-weightlifting-athletes-100620763",false,"NCT07361848","Long-Hold Yielding Isometric Exercise for Patellar Tendinopathy in Weightlifting Athletes","Randomized Controlled Trial Evaluating the Effects of Long-Hold Yielding Isometric Exercise on Pain, Function, Vascularity, and Mechanical Properties of the Patellar Tendon in Competitive Weightlifting Athletes","QuantFlow","Inclusion Criteria:\n\n1. Competitive weightlifting athletes (Olympic weightlifting or CrossFit) training ≥3 times per week.\n2. Age 18-45 years.\n3. Symptom duration of at least 6 weeks.\n4. Presence of vascularized patellar tendinopathy, defined as Doppler-detectable intratendinous neovascularization using standardized settings.\n5. VISA-P score \\\u003C 80 at baseline.\n6. Ability to perform loaded lower-limb exercises safely.\n7. Willingness to refrain from other structured isometric interventions focused on the patellar tendon during the study period.\n8. Ability to provide informed consent.\n9. Sex\u002FGender requirement: both men and women eligible; the study includes sex-stratified analysis to examine potential sex-based differences in tendon response.\n\nExclusion Criteria:\n\n1. Previous knee surgery within the past 12 months.\n2. Partial or complete patellar tendon rupture (confirmed clinically or by ultrasound).\n3. Coexisting knee conditions (e.g., meniscal tear, ACL\u002FPCL injury, patellofemoral joint instability) that significantly affect load tolerance.\n4. Systemic diseases affecting tendon health (e.g., diabetes, rheumatoid arthritis, connective tissue disorders).\n5. Corticosteroid injection in the patellar tendon within the last 6 months.\n6. Participation in other clinical trials involving exercise or tendon-loading interventions.\n7. Neuromuscular or medical conditions limiting safe performance of isometric or plyometric exercise.\n8. Pregnancy.\n9. Inability to commit to follow-up assessments at 8, 12, and 24 weeks.","ALL","18 Years","45 Years",{"count":93,"type":94},24,"ESTIMATED","INTERVENTIONAL",[97],"NA","The goal of this clinical trial is to evaluate whether a long-hold yielding isometric exercise program improves pain, tendon vascularity, mechanical properties, and functional performance in weightlifting athletes with patellar tendinopathy. The study will also explore the safety and feasibility of this exercise strategy.\n\nResearchers will compare the long-hold isometric intervention with routine training recommendations to determine its effects on symptoms and tendon function.\n\nParticipants will perform the supervised isometric protocol and complete pain ratings, functional tests, and ultrasound evaluations of the patellar tendon.",[100],"Patellar Tendinopathy \u002F Jumpers Knee",[102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124],"patellar tendinopathy","long hold yielding isometrics","weightlifting athletes","tendon vascularity","shear-wave elastography","quantitative ultrasound","echotexture","echostructure","ehointensity","echovariation","doppler imaging","tendon stifness","stress-strain curve","young's modulus","biomechanics","jumper's knee","iPulley isokinetic","countermovement jump","force platform biomechanics","tissue mechanical properties","musculoskeletal imaging","clincal trial","randomized controlled trial","NOT_YET_RECRUITING","2026-01-14",{"date":128,"type":129},"2026-01-23","ACTUAL",{"date":131,"type":94},"2027-02-01",{"date":133,"type":94},"2028-04-01",{"name":5,"class":6},1]