{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T14:14:25Z","timestamp":1788444865239,"version":"build-2803163510"},"reference-count":43,"publisher":"BMJ","issue":"6","license":[{"start":{"date-parts":[[2026,6,9]],"date-time":"2026-06-09T00:00:00Z","timestamp":1780963200000},"content-version":"unspecified","delay-in-days":8,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100013514","name":"Wereld Kanker Onderzoek Fonds","doi-asserted-by":"crossref","award":["IIG_FULL_2023_003"],"award-info":[{"award-number":["IIG_FULL_2023_003"]}],"id":[{"id":"10.13039\/501100013514","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/100013743","name":"World Cancer Research Fund International","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100013743","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Open"],"accepted":{"date-parts":[[2026,5,21]]},"published-print":{"date-parts":[[2026,6]]},"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>Approximately 40% of women stop endocrine therapy for hormone-receptor-positive breast cancer within the first 5 years of prescribed treatment because of side effects. Musculoskeletal complaints are among the most frequently reported side effects. The Cancer Of the BReast Asanas (COBRA) study examines the effect of an 18-week yoga programme on endocrine therapy-associated musculoskeletal complaints in women with breast cancer.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods and analysis<\/jats:title>\n                    <jats:p>In total, 140\u2009women will be randomised in a 1:1 ratio to the intervention or waitlist control group. The intervention programme consists of two times a week 1-hour supervised Hatha or (easy) Vinyasa yoga classes at a yoga or sports centre for 18\u2009weeks and once per week a half-hour at home using videos. The waitlist control group is asked to maintain their habitual lifestyle during the first 18\u2009weeks and will participate in a similar yoga programme to the intervention group for the following 18\u2009weeks. The control group yoga programme is offered live-remote. The primary outcome (musculoskeletal complaints) is assessed with the Brief Pain Inventory questionnaire at baseline and 18\u2009weeks (primary comparison) and additionally at 36\u2009weeks. Secondary outcomes include lower and upper extremity joint complaints, menopausal symptoms, fatigue, sleep, quality of life, anxiety and depression, cognitive complaints and habitual physical activity (all patient-reported), vital signs and anthropometrics, physical fitness, blood biomarkers, medication use, safety data and patient and teacher experiences. At baseline and 18\u2009weeks, cognitive complaints are also assessed with an online neuropsychological test battery.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Ethics and dissemination<\/jats:title>\n                    <jats:p>The COBRA study was approved by the Medical Ethical Committee of the University Medical Center Utrecht. The study started on 8 October 2024, and 65 participants have been included (20 January 2026). Results will be submitted to an international peer-reviewed journal.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Trial registration number<\/jats:title>\n                    <jats:p>\n                      <jats:ext-link xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" ext-link-type=\"clintrialgov\" xlink:href=\"NCT06480513\">NCT06480513<\/jats:ext-link>\n                      .\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.1136\/bmjopen-2026-117251","type":"journal-article","created":{"date-parts":[[2026,6,9]],"date-time":"2026-06-09T11:50:38Z","timestamp":1781005838000},"page":"e117251","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":0,"title":["Effect of yoga on musculoskeletal complaints in women during endocrine treatment for breast cancer: protocol of the randomised controlled COBRA trial"],"prefix":"10.1136","volume":"16","clinical-trial-number":[{"clinical-trial-number":"nct06480513","registry":"10.18810\/clinical-trials-gov"},{"clinical-trial-number":"nct06480513","registry":"10.18810\/clinical-trials-gov"}],"author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2426-1961","authenticated-orcid":false,"given":"Stefanie G A","family":"Veenhuizen","sequence":"first","affiliation":[{"name":"Julius Center for Health Sciences and Primary Care, Department of Epidemiology & Health Economics, University Medical Center Utrecht, Utrecht, The Netherlands"},{"name":"Utrecht University, Utrecht, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7340-4581","authenticated-orcid":false,"given":"Roxanne","family":"Gal","sequence":"additional","affiliation":[{"name":"Division of Imaging and Oncology, University Medical Center Utrecht, Utrecht, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Holger","family":"Cramer","sequence":"additional","affiliation":[{"name":"Institute of General Practice and Interprofessional Care, University Hospital T\u00fcbingen, T\u00fcbingen, Germany"},{"name":"Robert Bosch Center for Integrative Medicine and Health, Bosch Health Campus, Stuttgart, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rhod\u00e9 M","family":"Bijlsma","sequence":"additional","affiliation":[{"name":"Department of Medical Oncology, University Medical Center Utrecht, Utrecht, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9260-5610","authenticated-orcid":false,"given":"Patricia","family":"Blickle","sequence":"additional","affiliation":[{"name":"Division of Physical Activity, Cancer Prevention and Survivorship, German Cancer Research Center (DKFZ), Heidelberg, Germany"},{"name":"Division of Physical Activity, Cancer Prevention and Survivorship, a partnership between DKFZ and University Medical Center, National Center of Tumor Diseases (NCT), Heidelberg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1071-6769","authenticated-orcid":false,"given":"Job","family":"van der Palen","sequence":"additional","affiliation":[{"name":"Department of Epidemiology, Medisch Spectrum Twente, Enschede, The Netherlands"},{"name":"Section Cognition, Data and Education, Faculty of Behavioural, Management and Social Sciences, University of Twente, Enschede, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Quinty R C M","family":"Wagenaar","sequence":"additional","affiliation":[{"name":"Julius Center for Health Sciences and Primary Care, Department of Epidemiology & Health Economics, University Medical Center Utrecht, Utrecht, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Esther","family":"van Leer","sequence":"additional","affiliation":[{"name":"Department of Medical Oncology, University Medical Center Utrecht, Utrecht, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Inge","family":"Konings","sequence":"additional","affiliation":[{"name":"Department of Medical Oncology, Cancer Center Amsterdam, Amsterdam University Medical Center, Amsterdam, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Desir\u00e9e H J G","family":"van den Bongard","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, Cancer Center Amsterdam, Amsterdam University Medical Center, Amsterdam, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0643-3790","authenticated-orcid":false,"given":"Anne M","family":"May","sequence":"additional","affiliation":[{"name":"Julius Center for Health Sciences and Primary Care, Department of Epidemiology & Health Economics, University Medical Center Utrecht, Utrecht, The Netherlands"},{"name":"Division of Psychosocial Research and Epidemiology, The Netherlands Cancer Institute, Amsterdam, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Evelyn M","family":"Monninkhof","sequence":"additional","affiliation":[{"name":"Julius Center for Health Sciences and Primary Care, Department of Epidemiology & Health Economics, University Medical Center Utrecht, Utrecht, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2026,6,9]]},"reference":[{"key":"2026090306264857000_16.6.e117251.1","doi-asserted-by":"publisher","DOI":"10.3322\/CAAC.21834"},{"key":"2026090306264857000_16.6.e117251.2","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMoa1604700"},{"key":"2026090306264857000_16.6.e117251.3","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(12)61963-1"},{"key":"2026090306264857000_16.6.e117251.4","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.2014.57.6926"},{"key":"2026090306264857000_16.6.e117251.5","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.2011.38.0261"},{"key":"2026090306264857000_16.6.e117251.6","doi-asserted-by":"crossref","first-page":"567","DOI":"10.1007\/s10549-022-06583-7","article-title":"Discontinuation of adjuvant endocrine therapy and impact on quality of life and functional status in older patients with breast cancer","volume":"193","author":"Lemij","year":"2022","journal-title":"Breast Cancer Res Treat"},{"key":"2026090306264857000_16.6.e117251.7","doi-asserted-by":"crossref","first-page":"603","DOI":"10.1016\/S0140-6736(25)01013-X","article-title":"Extending the duration of endocrine treatment for early breast cancer: patient-level meta-analysis of 12 randomised trials of aromatase inhibitors in 22\u2008031 postmenopausal women already treated with at least 5 years of endocrine therapy","volume":"406","author":"Braybrooke","year":"2025","journal-title":"The Lancet"},{"key":"2026090306264857000_16.6.e117251.8","doi-asserted-by":"crossref","first-page":"1101","DOI":"10.1080\/14737140.2018.1520096","article-title":"Managing side effects in adjuvant endocrine therapy for breast cancer","volume":"18","author":"Condorelli","year":"2018","journal-title":"Expert Rev Anticancer Ther"},{"key":"2026090306264857000_16.6.e117251.9","doi-asserted-by":"publisher","DOI":"10.1016\/j.critrevonc.2017.01.010"},{"key":"2026090306264857000_16.6.e117251.10","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.2014.57.1547"},{"key":"2026090306264857000_16.6.e117251.11","doi-asserted-by":"crossref","unstructured":"Roberts KE , Rickett K , Feng S , et al . Exercise therapies for preventing or treating aromatase inhibitor-induced musculoskeletal symptoms in early breast cancer. Cochrane Database Syst Rev 2020;1. doi:10.1002\/14651858.CD012988.pub2","DOI":"10.1002\/14651858.CD012988.pub2"},{"key":"2026090306264857000_16.6.e117251.12","doi-asserted-by":"publisher","DOI":"10.1089\/acm.2009.0044"},{"key":"2026090306264857000_16.6.e117251.13","first-page":"322","article-title":"Effects of an 8-month yoga intervention on arterial compliance and muscle strength in premenopausal women","volume":"11","author":"Kim","year":"2012","journal-title":"J Sports Sci Med"},{"key":"2026090306264857000_16.6.e117251.14","doi-asserted-by":"crossref","unstructured":"Sivaramakrishnan D , Fitzsimons C , Kelly P , et al . The effects of yoga compared to active and inactive controls on physical function and health related quality of life in older adults- systematic review and meta-analysis of randomised controlled trials. Int J Behav Nutr Phys Act 2019;16. doi:10.1186\/s12966-019-0789-2","DOI":"10.1186\/s12966-019-0789-2"},{"key":"2026090306264857000_16.6.e117251.15","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.2013.51.8860"},{"key":"2026090306264857000_16.6.e117251.16","doi-asserted-by":"crossref","first-page":"830","DOI":"10.1002\/da.22762","article-title":"Yoga for anxiety: a systematic review and meta-analysis of randomized controlled trials","volume":"35","author":"Cramer","year":"2018","journal-title":"Depress Anxiety"},{"key":"2026090306264857000_16.6.e117251.17","doi-asserted-by":"publisher","DOI":"10.1002\/da.22166"},{"key":"2026090306264857000_16.6.e117251.18","doi-asserted-by":"publisher","DOI":"10.1002\/cncr.26702"},{"key":"2026090306264857000_16.6.e117251.19","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.2012.43.7707"},{"key":"2026090306264857000_16.6.e117251.20","doi-asserted-by":"publisher","DOI":"10.1177\/1534735411413270"},{"key":"2026090306264857000_16.6.e117251.21","doi-asserted-by":"publisher","DOI":"10.1007\/s00520-009-0587-5"},{"key":"2026090306264857000_16.6.e117251.22","doi-asserted-by":"crossref","unstructured":"Tsai C-L , Liu L-C , Liao C-Y , et al . Yoga versus massage in the treatment of aromatase inhibitor-associated knee joint pain in breast cancer survivors: a randomized controlled trial. Sci Rep 2021;11. doi:10.1038\/s41598-021-94466-0","DOI":"10.1038\/s41598-021-94466-0"},{"key":"2026090306264857000_16.6.e117251.23","doi-asserted-by":"crossref","first-page":"597","DOI":"10.1007\/s10549-015-3351-1","article-title":"The effect of YOCAS\u00a9\u00ae yoga for musculoskeletal symptoms among breast cancer survivors on hormonal therapy","volume":"150","author":"Peppone","year":"2015","journal-title":"Breast Cancer Res Treat"},{"key":"2026090306264857000_16.6.e117251.24","first-page":"129","article-title":"Pain assessment: global use of the Brief Pain Inventory","volume":"23","author":"Cleeland","year":"1994","journal-title":"Ann Acad Med Singap"},{"key":"2026090306264857000_16.6.e117251.25","doi-asserted-by":"publisher","DOI":"10.1007\/s11136-013-0362-4"},{"key":"2026090306264857000_16.6.e117251.26","first-page":"1833","article-title":"Validation study of WOMAC: a health status instrument for measuring clinically important patient relevant outcomes to antirheumatic drug therapy in patients with osteoarthritis of the hip or knee","volume":"15","author":"Bellamy","year":"1988","journal-title":"J Rheumatol"},{"key":"2026090306264857000_16.6.e117251.27","doi-asserted-by":"publisher","DOI":"10.1093\/jnci\/85.5.365"},{"key":"2026090306264857000_16.6.e117251.28","doi-asserted-by":"crossref","first-page":"283","DOI":"10.1016\/j.annonc.2019.10.027","article-title":"An international update of the EORTC questionnaire for assessing quality of life in breast cancer patients: EORTC QLQ-BR45","volume":"31","author":"Bjelic-Radisic","year":"2020","journal-title":"Ann Oncol"},{"key":"2026090306264857000_16.6.e117251.29","doi-asserted-by":"publisher","DOI":"10.1023\/a:1006263818115"},{"key":"2026090306264857000_16.6.e117251.30","doi-asserted-by":"publisher","DOI":"10.1016\/0022-3999(94)00125-O"},{"key":"2026090306264857000_16.6.e117251.31","doi-asserted-by":"publisher","DOI":"10.1111\/j.1600-0447.1983.tb09716.x"},{"key":"2026090306264857000_16.6.e117251.32","doi-asserted-by":"publisher","DOI":"10.1016\/0165-1781(89)90047-4"},{"key":"2026090306264857000_16.6.e117251.33","doi-asserted-by":"publisher","DOI":"10.1016\/S0895-4356(03)00220-8"},{"key":"2026090306264857000_16.6.e117251.34","first-page":"W32","article-title":"Measuring patient self-reported cognitive function: development of the functional assessment of cancer therapy-cognitive function instrument","volume":"7","author":"Wagner","year":"2009","journal-title":"J Support Oncol"},{"key":"2026090306264857000_16.6.e117251.35","doi-asserted-by":"crossref","unstructured":"Feenstra HE , Vermeulen IE , Murre JM , et al . Online self-administered cognitive testing using the amsterdam cognition scan: establishing psychometric properties and normative data. J Med Internet Res 2018;20. doi:10.2196\/jmir.9298","DOI":"10.2196\/jmir.9298"},{"key":"2026090306264857000_16.6.e117251.36","doi-asserted-by":"publisher","DOI":"10.1080\/13803395.2017.1339017"},{"key":"2026090306264857000_16.6.e117251.37","doi-asserted-by":"publisher","DOI":"10.1016\/j.apmr.2007.02.013"},{"key":"2026090306264857000_16.6.e117251.38","doi-asserted-by":"crossref","unstructured":"Spence RR , Sandler CX , Jones TL , et al . Practical suggestions for harms reporting in exercise oncology: the Exercise Harms Reporting Method (ExHaRM). BMJ Open 2022;12. doi:10.1136\/bmjopen-2022-067998","DOI":"10.1136\/bmjopen-2022-067998"},{"key":"2026090306264857000_16.6.e117251.39","doi-asserted-by":"publisher","DOI":"10.1016\/j.ctim.2011.07.004"},{"key":"2026090306264857000_16.6.e117251.40","first-page":"1077","article-title":"Mind-body medicine use by women diagnosed with breast cancer: results of a nationally representative survey","volume":"28","author":"Voi\u00df","year":"2020","journal-title":"Support Care Cancer"},{"key":"2026090306264857000_16.6.e117251.41","doi-asserted-by":"publisher","DOI":"10.1186\/1472-6874-7-4"},{"key":"2026090306264857000_16.6.e117251.42","doi-asserted-by":"crossref","unstructured":"Myers SA , Weller S , Schwartz S , et al . Feasibility of a supervised virtual exercise program for women on hormone therapy for breast cancer. Transl J ACSM 2022;7. doi:10.1249\/TJX.0000000000000213","DOI":"10.1249\/TJX.0000000000000213"},{"key":"2026090306264857000_16.6.e117251.43","doi-asserted-by":"crossref","unstructured":"Haynes A , Gilchrist H , Oliveira JS , et al . \u201cI wouldn\u2019t have joined if it wasn\u2019t online\u201d: understanding older people\u2019s engagement with teleyoga classes for fall prevention. BMC Complement Med Ther 2022;22. doi:10.1186\/s12906-022-03756-1","DOI":"10.1186\/s12906-022-03756-1"}],"container-title":["BMJ Open"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/bmjopen-2026-117251","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T13:28:07Z","timestamp":1788442087000},"score":1,"resource":{"primary":{"URL":"https:\/\/bmjopen.bmj.com\/lookup\/doi\/10.1136\/bmjopen-2026-117251"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,6]]},"references-count":43,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2026,6,9]]},"published-print":{"date-parts":[[2026,6]]}},"alternative-id":["10.1136\/bmjopen-2026-117251"],"URL":"https:\/\/doi.org\/10.1136\/bmjopen-2026-117251","relation":{},"ISSN":["2044-6055","2044-6055"],"issn-type":[{"value":"2044-6055","type":"print"},{"value":"2044-6055","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,6]]}}}