{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T21:50:34Z","timestamp":1790113834977,"version":"4.0.1"},"reference-count":50,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"1","content-domain":{"domain":["lww.com","ovid.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2026,3]]},"abstract":"<jats:p>Quadriceps muscle weakness is a common clinical feature in individuals with knee osteoarthritis (KOA) and contributes to pain, functional limitations, and reduced quality of life. While quadriceps strengthening exercises are well-established, the additional benefits of electromyographic biofeedback (EMG-BFB) and neuromuscular electrical stimulation (NMES) remain inconclusive. This single-blind randomized controlled trial investigated whether EMG-BFB or NMES provides added benefits when combined with isometric quadriceps strengthening exercises in patients with mild-to-moderate KOA. Ninety-three participants aged over 55 years, meeting the American College of Rheumatology criteria and classified as Kellgren\u2013Lawrence grades 1\u20132, were randomly assigned to three groups: exercise only, exercise plus EMG-BFB, and exercise plus NMES. All participants completed 15 supervised sessions over 3 weeks. Pain intensity (Visual Analogue Scale) was the primary outcome. Secondary outcomes included physical function (Western Ontario and McMaster Universities Osteoarthritis Index), muscle activation (raw EMG amplitude), and quality of life (36-Item Short Form Health Survey), assessed at baseline, immediately after the intervention, and at 3- and 6-month follow-up. All groups demonstrated significant improvements in pain, knee function, muscle activation, and quality of life following the intervention, with benefits maintained at follow-up. However, no significant differences were observed between groups at any time point. These results suggest that isometric quadriceps strengthening exercises alone are effective in managing KOA, while the addition of EMG-BFB or NMES does not yield superior clinical outcomes. Given the simplicity, accessibility, and effectiveness of exercise alone, it may serve as a first-line intervention, while the specific clinical indications for adding EMG-BFB and NMES to isometric exercises remain to be determined.<\/jats:p>","DOI":"10.1097\/mrr.0000000000000689","type":"journal-article","created":{"date-parts":[[2026,1,8]],"date-time":"2026-01-08T15:00:23Z","timestamp":1767884423000},"page":"3-10","update-policy":"https:\/\/doi.org\/10.1097\/lww.0000000000001000","source":"Crossref","is-referenced-by-count":2,"title":["Electromyographic biofeedback or neuromuscular electrical stimulation added to isometric quadriceps exercise does not improve pain and functional outcomes in knee osteoarthritis: a randomized controlled trial"],"prefix":"10.1097","volume":"49","author":[{"given":"Silvija","family":"Mahnik","sequence":"first","affiliation":[{"name":"Department of Orthopedic Surgery, University Hospital Center Zagreb, School of Medicine, University of Zagreb"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ana","family":"Aljinovi\u0107","sequence":"additional","affiliation":[{"name":"Department of Orthopedic Surgery, University Hospital Center Zagreb, School of Medicine, University of Zagreb"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alan","family":"Mahnik","sequence":"additional","affiliation":[{"name":"Department of Orthopedic Surgery, University Hospital Center Zagreb, School of Medicine, University of Zagreb"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pero","family":"Hraba\u010d","sequence":"additional","affiliation":[{"name":"Department of Medical Statistics, Epidemiology, and Medical Informatics, Andrija \u0160tampar School of Public Health"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Monika","family":"\u017dab\u010di\u0107","sequence":"additional","affiliation":[{"name":"Department of Orthopedic Surgery, University Hospital Center Zagreb, School of Medicine, University of Zagreb"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ivan","family":"Bojani\u0107","sequence":"additional","affiliation":[{"name":"Department of Orthopedic Surgery, University Hospital Centre Zagreb, University of Zagreb School of Medicine, Zagreb, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"276","published-online":{"date-parts":[[2026,1,8]]},"reference":[{"key":"R1-20260205","doi-asserted-by":"crossref","first-page":"1697","DOI":"10.1002\/art.34453","article-title":"Osteoarthritis: a disease of the joint as an organ.","volume":"64","author":"Loeser","year":"2012","journal-title":"Arthritis Rheuma"},{"key":"R2-20260205","doi-asserted-by":"crossref","first-page":"364","DOI":"10.1186\/s12891-022-05306-9","article-title":"The economic burden of knee and hip osteoarthritis: absenteeism and costs in the Dutch workforce.","volume":"23","author":"Hardenberg","year":"2022","journal-title":"BMC Musculoskelet Disord"},{"key":"R3-20260205","doi-asserted-by":"crossref","first-page":"203","DOI":"10.1002\/acr.22412","article-title":"Lifetime medical costs of knee osteoarthritis management in the United States: impact of extending indications for total knee arthroplasty.","volume":"67","author":"Losina","year":"2015","journal-title":"Arthritis Care Res (Hoboken)"},{"key":"R4-20260205","doi-asserted-by":"crossref","first-page":"84","DOI":"10.23736\/S1973-9087.23.08071-1","article-title":"Clinical prediction model for interdisciplinary biopsychosocial rehabilitation in osteoarthritis patients.","volume":"60","author":"Vervullens","year":"2024","journal-title":"Eur J Phys Rehabil Med"},{"key":"R5-20260205","doi-asserted-by":"crossref","first-page":"184","DOI":"10.1016\/j.joca.2021.04.020","article-title":"Epidemiology of osteoarthritis.","volume":"30","author":"Allen","year":"2022","journal-title":"Osteoarthritis Cartilage"},{"key":"R6-20260205","doi-asserted-by":"crossref","first-page":"S245","DOI":"10.21037\/atm.2019.06.68","article-title":"Non-operative treatment options for knee osteoarthritis.","volume":"7","author":"DeRogatis","year":"2019","journal-title":"Ann Transl Med"},{"key":"R7-20260205","doi-asserted-by":"crossref","first-page":"559","DOI":"10.1016\/j.apmr.2021.07.801","article-title":"Cross-sectional analysis of recommendations for the treatment of hip and knee osteoarthritis in clinical guidelines.","volume":"103","author":"Bichsel","year":"2022","journal-title":"Arch Phys Med Rehabil"},{"key":"R8-20260205","doi-asserted-by":"crossref","first-page":"1578","DOI":"10.1016\/j.joca.2019.06.011","article-title":"OARSI guidelines for the non-surgical management of knee, hip, and polyarticular osteoarthritis.","volume":"27","author":"Bannuru","year":"2019","journal-title":"Osteoarthritis Cartilage"},{"key":"R9-20260205","doi-asserted-by":"crossref","first-page":"e721","DOI":"10.5435\/JAAOS-D-21-01233","article-title":"AAOS clinical practice guideline summary: management of osteoarthritis of the knee (nonarthroplasty), third edition.","volume":"30","author":"Brophy","year":"2022","journal-title":"J Am Acad Orthop Surg"},{"key":"R10-20260205","doi-asserted-by":"crossref","first-page":"730","DOI":"10.1136\/ard-2023-225041","article-title":"EULAR recommendations for the non-pharmacological core management of hip and knee osteoarthritis: 2023 update.","volume":"83","author":"Moseng","year":"2024","journal-title":"Ann Rheum Dis"},{"key":"R11-20260205","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1136\/bmj.p24","article-title":"Osteoarthritis in people over 16: diagnosis and management-updated summary of NICE guidance.","volume":"380","author":"Wood","year":"2023","journal-title":"BMJ"},{"key":"R12-20260205","doi-asserted-by":"crossref","first-page":"220","DOI":"10.1002\/art.41142","article-title":"2019 American College of Rheumatology\/Arthritis Foundation Guideline for the Management of Osteoarthritis of the Hand, Hip, and Knee.","volume":"72","author":"Kolasinski","year":"2020","journal-title":"Arthritis Rheumatol"},{"key":"R13-20260205","doi-asserted-by":"crossref","first-page":"1280","DOI":"10.1016\/j.joca.2023.05.015","article-title":"Recommendations for the management of hip and knee osteoarthritis: a systematic review of clinical practice guidelines.","volume":"31","author":"Gibbs","year":"2023","journal-title":"Osteoarthritis Cartilage"},{"key":"R14-20260205","doi-asserted-by":"crossref","first-page":"23259671231172773","DOI":"10.1177\/23259671231172773","article-title":"Exercise therapy for knee osteoarthritis: a systematic review and network meta-analysis.","volume":"11","author":"Mo","year":"2023","journal-title":"Orthop J Sports Med"},{"key":"R15-20260205","doi-asserted-by":"crossref","first-page":"e093163","DOI":"10.1136\/bmjopen-2024-093163","article-title":"Effectiveness of exercise therapy in patients with knee osteoarthritis: an overview of systematic reviews.","volume":"15","author":"Kitagawa","year":"2025","journal-title":"BMJ Open"},{"key":"R16-20260205","doi-asserted-by":"crossref","first-page":"2231","DOI":"10.1016\/j.asjsur.2024.11.179","article-title":"Isometric exercise for knee osteoarthritis: a systematic review and meta-analysis.","volume":"48","author":"Yang","year":"2025","journal-title":"Asian J Surg"},{"key":"R17-20260205","doi-asserted-by":"crossref","first-page":"284","DOI":"10.1177\/1941738112445726","article-title":"Muscle impairments in patients with knee osteoarthritis.","volume":"4","author":"Alnahdi","year":"2012","journal-title":"Sports Health"},{"key":"R18-20260205","doi-asserted-by":"crossref","first-page":"e2062","DOI":"10.1002\/pri.2062","article-title":"Effectiveness of neuromuscular electrical stimulation training combined with exercise on patient-reported outcomes measures in people with knee osteoarthritis: a systematic review and meta-analysis.","volume":"29","author":"Carvalho","year":"2024","journal-title":"Physiother Res Int"},{"key":"R19-20260205","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1001\/jama.1997.03540250033028","article-title":"A randomized trial comparing aerobic exercise and resistance exercise with a health education program in older adults with knee osteoarthritis. The Fitness Arthritis and Seniors Trial (FAST).","volume":"277","author":"Ettinger","year":"1997","journal-title":"JAMA"},{"key":"R20-20260205","doi-asserted-by":"crossref","first-page":"100457","DOI":"10.1016\/j.ocarto.2024.100457","article-title":"Adjunctive electrophysical therapies used in addition to land-based exercise therapy for osteoarthritis of the hip or knee: a systematic review and meta-analysis.","volume":"6","author":"French","year":"2024","journal-title":"Osteoarthr Cartil Open"},{"key":"R21-20260205","doi-asserted-by":"crossref","first-page":"95","DOI":"10.1186\/s13018-025-05495-8","article-title":"A meta-analysis of randomized controlled trials: evaluating the efficacy of isokinetic muscle strengthening training in improving knee osteoarthritis outcomes.","volume":"20","author":"Guo","year":"2025","journal-title":"J Orthop Surg Res"},{"key":"R22-20260205","doi-asserted-by":"crossref","first-page":"853","DOI":"10.3233\/THC-161234","article-title":"Comparative effects of proprioceptive and isometric exercises on pain intensity and difficulty in patients with knee osteoarthritis: a randomised control study.","volume":"24","author":"Ojoawo","year":"2016","journal-title":"Technol Health Care"},{"key":"R23-20260205","doi-asserted-by":"crossref","first-page":"484","DOI":"10.1111\/sms.13375","article-title":"Isometric training and long-term adaptations: effects of muscle length, intensity, and intent: a systematic review.","volume":"29","author":"Oranchuk","year":"2019","journal-title":"Scand J Med Sci Sports"},{"key":"R24-20260205","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1016\/j.apnr.2004.06.004","article-title":"The effect of neuromuscular electrical stimulation on arthritis knee pain in older adults with osteoarthritis of the knee.","volume":"17","author":"Gaines","year":"2004","journal-title":"Appl Nurs Res"},{"key":"R25-20260205","doi-asserted-by":"crossref","first-page":"511","DOI":"10.1002\/jor.22264","article-title":"Neuromuscular electrical stimulation (NMES) reduces structural and functional losses of quadriceps muscle and improves health status in patients with knee osteoarthritis.","volume":"31","author":"Vaz","year":"2013","journal-title":"J Orthop Res"},{"key":"R26-20260205","doi-asserted-by":"crossref","first-page":"1441","DOI":"10.2522\/ptj.20090330","article-title":"A clinical trial of neuromuscular electrical stimulation in improving quadriceps muscle strength and activation among women with mild and moderate osteoarthritis.","volume":"90","author":"Palmieri-Smith","year":"2010","journal-title":"Phys Ther"},{"key":"R27-20260205","doi-asserted-by":"crossref","first-page":"118","DOI":"10.1186\/1471-2474-13-118","article-title":"Effects of home-based resistance training and neuromuscular electrical stimulation in knee osteoarthritis: a randomized controlled trial.","volume":"13","author":"Bruce-Brand","year":"2012","journal-title":"BMC Musculoskelet Disord"},{"key":"R28-20260205","doi-asserted-by":"crossref","first-page":"674","DOI":"10.1007\/s10067-006-0358-3","article-title":"Effects of quadriceps electrical stimulation program on clinical parameters in the patients with knee osteoarthritis.","volume":"26","author":"Durmus","year":"2007","journal-title":"Clin Rheumatol"},{"key":"R29-20260205","doi-asserted-by":"crossref","first-page":"293","DOI":"10.2340\/16501977-2062","article-title":"Effects of neuromuscular electrical stimulation and low-level laser therapy on neuromuscular parameters and health status in elderly women with knee osteoarthritis: a randomized trial.","volume":"48","author":"de Oliveira Melo","year":"2016","journal-title":"J Rehabil Med"},{"key":"R30-20260205","doi-asserted-by":"crossref","first-page":"246","DOI":"10.1177\/0269215512456388","article-title":"Does neuromuscular electrical stimulation enhance the effectiveness of an exercise programme in subjects with knee osteoarthritis? A randomized controlled trial.","volume":"27","author":"Elboim-Gabyzon","year":"2013","journal-title":"Clin Rehabil"},{"key":"R31-20260205","doi-asserted-by":"crossref","first-page":"1153","DOI":"10.2147\/CIA.S64104","article-title":"The effects of exercise and neuromuscular electrical stimulation in subjects with knee osteoarthritis: a 3-month follow-up study.","volume":"9","author":"Laufer","year":"2014","journal-title":"Clin Interv Aging"},{"key":"R32-20260205","doi-asserted-by":"crossref","first-page":"158","DOI":"10.1186\/s12891-024-07266-8","article-title":"A controlled randomized trial with a 12-week follow-up investigating the effects of medium-frequency neuromuscular electrical stimulation on pain, VMO thickness, and functionality in patients with knee osteoarthritis.","volume":"25","author":"Moezy","year":"2024","journal-title":"BMC Musculoskelet Disord"},{"key":"R33-20260205","doi-asserted-by":"crossref","first-page":"688260","DOI":"10.3389\/fphys.2021.688260","article-title":"Influence of isometric exercise combined with electromyostimulation on inflammatory cytokine levels, muscle strength, and knee joint function in elderly women with early knee osteoarthritis.","volume":"12","author":"Park","year":"2021","journal-title":"Front Physiol"},{"key":"R34-20260205","doi-asserted-by":"crossref","first-page":"203","DOI":"10.1007\/s00296-018-4199-6","article-title":"Strengthening the quadriceps femoris muscle versus other knee training programs for the treatment of knee osteoarthritis.","volume":"39","author":"Kus","year":"2019","journal-title":"Rheumatol Int"},{"key":"R35-20260205","doi-asserted-by":"crossref","first-page":"101662","DOI":"10.1016\/j.rehab.2022.101662","article-title":"Neuromuscular joint function in knee osteoarthritis: a systematic review and meta-analysis.","volume":"66","author":"Tayfur","year":"2023","journal-title":"Ann Phys Rehabil Med"},{"key":"R36-20260205","doi-asserted-by":"crossref","first-page":"60","DOI":"10.1186\/1743-0003-10-60","article-title":"Biofeedback in rehabilitation.","volume":"10","author":"Giggins","year":"2013","journal-title":"J Neuroeng Rehabil"},{"key":"R37-20260205","doi-asserted-by":"crossref","first-page":"2781","DOI":"10.2147\/JPR.S169613","article-title":"The efficacy of electromyographic biofeedback on pain, function, and maximal thickness of vastus medialis oblique muscle in patients with knee osteoarthritis: a randomized clinical trial.","volume":"11","author":"Raeissadat","year":"2018","journal-title":"J Pain Res"},{"key":"R38-20260205","doi-asserted-by":"crossref","first-page":"887","DOI":"10.1007\/s00296-009-1070-9","article-title":"Efficacy of EMG-biofeedback in knee osteoarthritis.","volume":"30","author":"Yilmaz","year":"2010","journal-title":"Rheumatol Int"},{"key":"R39-20260205","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1589\/jpts.27.149","article-title":"Effects of isometric exercise using biofeedback on maximum voluntary isometric contraction, pain, and muscle thickness in patients with knee osteoarthritis.","volume":"27","author":"Choi","year":"2015","journal-title":"J Phys Ther Sci"},{"key":"R40-20260205","doi-asserted-by":"crossref","first-page":"547","DOI":"10.1186\/s12891-025-08794-7","article-title":"Effectiveness of stationary cycling with electromyographic biofeedback on neuromuscular control and function in individuals with knee osteoarthritis: a feasibility study.","volume":"26","author":"Chang","year":"2025","journal-title":"BMC Musculoskelet Disord"},{"key":"R41-20260205","first-page":"1","article-title":"EMG-force relationships in skeletal muscle.","volume":"7","author":"Perry","year":"1981","journal-title":"Crit Rev Biomed Eng"},{"key":"R42-20260205","doi-asserted-by":"crossref","first-page":"110","DOI":"10.1016\/S0736-0266(03)00154-2","article-title":"Quadriceps femoris muscle weakness and activation failure in patients with symptomatic knee osteoarthritis.","volume":"22","author":"Lewek","year":"2004","journal-title":"J Orthop Res"},{"key":"R43-20260205","doi-asserted-by":"crossref","first-page":"96","DOI":"10.1016\/S0736-0266(03)00128-1","article-title":"Strength and voluntary activation of the quadriceps femoris muscle at different severities of osteoarthritic knee joint damage.","volume":"22","author":"Pap","year":"2004","journal-title":"J Orthop Res"},{"key":"R44-20260205","doi-asserted-by":"crossref","first-page":"510","DOI":"10.1097\/00007632-199006000-00015","article-title":"Biofeedback in back muscle strengthening.","volume":"15","author":"Asfour","year":"1990","journal-title":"Spine (Phila Pa 1976)"},{"key":"R45-20260205","doi-asserted-by":"crossref","first-page":"1187","DOI":"10.1053\/apmr.2002.33988","article-title":"The effect of dynamic versus isometric resistance training on pain and functioning among adults with osteoarthritis of the knee.","volume":"83","author":"Topp","year":"2002","journal-title":"Arch Phys Med Rehabil"},{"key":"R46-20260205","doi-asserted-by":"crossref","first-page":"27","DOI":"10.1016\/j.ctcp.2012.09.002","article-title":"Neuromuscular electrical stimulation for muscle strengthening in elderly with knee osteoarthritis \u2013 a systematic review.","volume":"19","author":"de Oliveira Melo","year":"2013","journal-title":"Complement Ther Clin Pract"},{"key":"R47-20260205","doi-asserted-by":"crossref","first-page":"867","DOI":"10.1177\/0269215511431902","article-title":"Neuromuscular electrical stimulation in the treatment of knee osteoarthritis: a systematic review and meta-analysis.","volume":"26","author":"Giggins","year":"2012","journal-title":"Clin Rehabil"},{"key":"R48-20260205","doi-asserted-by":"crossref","first-page":"350","DOI":"10.1007\/s00402-025-05958-x","article-title":"The effectiveness of 6-week superimposed neuromuscular electrical stimulation in knee osteoarthritis: an assessor blinded randomized controlled clinical trial.","volume":"145","author":"Mete","year":"2025","journal-title":"Arch Orthop Trauma Surg"},{"key":"R49-20260205","doi-asserted-by":"crossref","first-page":"434","DOI":"10.1016\/j.rehab.2013.06.001","article-title":"Effect of gender on strength gains after isometric exercise coupled with electromyographic biofeedback in knee osteoarthritis: a preliminary study.","volume":"56","author":"Anwer","year":"2013","journal-title":"Ann Phys Rehabil Med"},{"key":"R50-20260205","doi-asserted-by":"crossref","first-page":"86","DOI":"10.1016\/j.hkpj.2011.06.006","article-title":"Effectiveness of electromyographic biofeedback training on quadriceps muscle strength in osteoarthritis of knee.","volume":"29","author":"Anwer","year":"2011","journal-title":"Hong Kong Physiother J"}],"container-title":["International Journal of Rehabilitation Research"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.ovid.com\/10.1097\/MRR.0000000000000689","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,6]],"date-time":"2026-08-06T20:22:47Z","timestamp":1786047767000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.ovid.com\/10.1097\/MRR.0000000000000689"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,1,8]]},"references-count":50,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2026]]}},"URL":"https:\/\/doi.org\/10.1097\/mrr.0000000000000689","relation":{},"ISSN":["0342-5282","1473-5660"],"issn-type":[{"value":"0342-5282","type":"print"},{"value":"1473-5660","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,1,8]]},"assertion":[{"value":"2025-08-12","name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-12-13","name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}}]}}