{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T14:38:42Z","timestamp":1787841522731,"version":"build-2784847793"},"reference-count":37,"publisher":"BMJ","issue":"3","license":[{"start":{"date-parts":[[2026,3,6]],"date-time":"2026-03-06T00:00:00Z","timestamp":1772755200000},"content-version":"unspecified","delay-in-days":5,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Open"],"accepted":{"date-parts":[[2026,2,19]]},"published-print":{"date-parts":[[2026,3]]},"abstract":"<jats:sec>\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>\n                      To examine the association between spinal mobility, disease activity, frailty and cardiorespiratory fitness (maximal oxygen uptake (VO\n                      <jats:sub>2<\/jats:sub>\n                      max)) in patients with ankylosing spondylitis (AS).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      A cross-sectional comparative study was conducted at the University of Lahore and seven government hospitals (March\u2013August 2025) including 74 patients with AS (40\u201355 years, modified New York criteria) and 77 age-matched and sex-matched healthy controls. Assessments included disease activity (Bath Ankylosing Spondylitis Disease Activity Index), functional limitation (Bath Ankylosing Spondylitis Functional Index), spinal mobility (Bath Ankylosing Spondylitis Metrology Index (BASMI)), chest expansion, frailty (Fatigue, Resistance, Ambulation, Illnesses, Loss of weight scale), pulmonary function and cardiorespiratory fitness (VO\n                      <jats:sub>2<\/jats:sub>\n                      max) via symptom-limited cardiopulmonary exercise testing. Functional performance was measured with the 6 min walk test (6MWT), and physical activity with the International Physical Activity Questionnaire (IPAQ). Data were analysed using t-tests, \u03c7\n                      <jats:sup>2<\/jats:sup>\n                      tests, correlations and regression models to examine associations between clinical measures and cardiorespiratory fitness.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      Among 151 participants (74 AS, 77 controls), AS patients showed significantly reduced pulmonary function (forced expiratory volume in one second 83.5% vs 91.2%, forced vital capacity 85.1% vs 93.0%), lower VO\n                      <jats:sub>2<\/jats:sub>\n                      max (27.8 vs 33.4 mL\/kg\/min), impaired spinal mobility (BASMI 5.1 vs 1.2) and decreased chest expansion (2.8 vs 5.6 cm; all p&lt;0.01). They also had shorter 6MWT distance, higher frailty and lower physical activity. VO\n                      <jats:sub>2<\/jats:sub>\n                      max was inversely correlated with disease activity, spinal stiffness, frailty and structural damage and positively correlated with chest expansion, 6MWT and activity levels. AS status, higher disease activity, greater spinal stiffness and reduced chest expansion independently predicted low physical activity.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>AS is associated with impaired pulmonary function, reduced spinal mobility and lower cardiorespiratory fitness, with disease activity, stiffness and restricted chest expansion potentially influencing physical activity and overall functional capacity.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1136\/bmjopen-2025-112382","type":"journal-article","created":{"date-parts":[[2026,3,6]],"date-time":"2026-03-06T14:35:39Z","timestamp":1772807739000},"page":"e112382","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":1,"title":["Impact of disease burden on VO\n                    <sub>2<\/sub>\n                    max, physical performance and frailty in ankylosing spondylitis: a comparative cross-sectional study"],"prefix":"10.1136","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0001-1606-280X","authenticated-orcid":false,"given":"Arsalan","family":"Tariq","sequence":"first","affiliation":[{"name":"University Institute of Physical Therapy, The University of Lahore, Lahore, Punjab, Pakistan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Muhammad","family":"Ammar","sequence":"additional","affiliation":[{"name":"Alhamd Islamic University, Quetta, Balochistan, Pakistan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Abdul","family":"Saad","sequence":"additional","affiliation":[{"name":"University Institute of Physical Therapy, The University of Lahore, Lahore, Punjab, Pakistan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sayed Alireza Mousavi","family":"Zadeh","sequence":"additional","affiliation":[{"name":"Department of Physical Education and Sports Science, Islamic Azad University Isfahan (Khorasgan) Branch, Isfahan, Iran (the Islamic Republic of)"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2026,3,6]]},"reference":[{"key":"2026062609353985000_16.3.e112382.1","doi-asserted-by":"publisher","DOI":"10.1111\/1756-185X.14547"},{"key":"2026062609353985000_16.3.e112382.2","doi-asserted-by":"publisher","DOI":"10.1093\/rheumatology\/ket387"},{"key":"2026062609353985000_16.3.e112382.3","doi-asserted-by":"crossref","first-page":"317","DOI":"10.5606\/ArchRheumatol.2019.7145","article-title":"Pulmonary Function, Aerobic Capacity and Related Variables in Patients With Ankylosing Spondylitis","volume":"34","author":"\u00c7a\u011fliyan T\u00fcrk","year":"2019","journal-title":"Arch Rheumatol"},{"key":"2026062609353985000_16.3.e112382.4","doi-asserted-by":"crossref","first-page":"490","DOI":"10.1111\/1756-185X.12347","article-title":"Aerobic capacity and its 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