MUSCLE ENDURANCE IN MYOSITIS Muscle endurance deficits in myositis patients despite normal manual muscle testing scores David R. Amici BS 1* , Iago Pinal-Fernandez MD PhD 1* , Ruben Pagkatipunan DPT 2 , Albert Mears DPT 2 , Rebecca De Lorenzo BS 1 , Eleni Tiniakou MD 2 , Jemima Albayda MD 2 , Julie J. Paik MD, MHS, Thomas E. Lloyd MD PhD 2 , Lisa Christopher-Stine MD MPH 2 , Andrew L Mammen MD PhD 1,2** , Tae Chung MD 2** *DRA and IPF, **ALM and TC contributed equally to the manuscript. 1. Muscle Disease Unit, National Institute of Arthritis and Musculoskeletal and Skin Diseases, Bethesda, MD, USA 2. Johns Hopkins University School of Medicine, Baltimore, MD, USA. Correspondence to: Tae Chung, tchung7@jhmi.edu, 410-550-9941, Johns Hopkins Bayview Medical Center Asthma Allergy Building 1A44, 4940 Eastern Ave, Baltimore, MD 21224 Acknowledgements: This work was financially supported by the Intramural Research Program of the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health. IPF is supported by a fellowship from The Myositis Association. TEL is supported by R01 NS082563 and NS094239. TC is supported by K12 5K12HD001097-19, Rehabilitation Medicine Scientist Program (RSMTP). LC-S is supported by the Huayi and Siuling Zhang Discovery Fund. Ethical Publication Statement: We confirm that we have read the Journal’s position on issues involved in ethical publication and affirm that this report is consistent with those guidelines. Disclosures of Conflicts of Interest: None of the authors has any conflict of interest to disclose. This article is protected by copyright. All rights reserved Accepted Article This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1002/mus.26307