Do mobility exercises in different environments have different effects in ankylosing spondylitis?

Aims: Ankylosing spondylitis (AS) reduces spinal mobility, which results in structural and functional impairments. Pulmonary problems eventually occur in most AS patients due to interstitial lung disease or as a result of chest wall abnormalities. The aim of this study was to evaluate the effects on pulmonary functions and disease related scales of aquatic and land-based multidimensional functional mobility exercises on pulmonary functions in patients with AS. Methods: In this randomized controlled study, 57 patients with definite AS according to the modified New York criteria were randomly allocated to an aquatic (AG), land-based (LG), or home (HG) exercise group and performed multidimensional mobility exercise sessions twice a week for 8 weeks. The Bath indices were used to measure disease activity, functional limitation, and spinal mobility, and a 10-cm visual analog scale assessed pain during activity and at rest. Pulmonary function tests, maximal inspiratory mouth pressure (MIP), and maximal expiratory mouth pressure (MEP) were measured before and after the intervention. The study is registered at ClinicalTrials.gov, number NCT03667625 (27/08/2018). Results: Forty-six patients (30.4% female) with a mean age of 42.0 years completed the study. Multidimensional exercises improved disease-related symptoms such as pain, spinal mobility, and functionality, but there were no significant changes in HG. Patients in AG showed significant improvements in peak expiratory flow (p=0.004), vital capacity (p=0.025), maximum voluntary ventilation (p=0.006), and MIP (p=0.001), while those in LG showed significant increases in forced expiratory volume during the first second to forced vital capacity (FEV1/FVC) ratio (p=0.049), peak expiratory flow (p=0.007), and maximum voluntary ventilation (p=0.004). There were no significant changes in HG. Conclusions: Multidimensional functional mobility exercises performed either in water or on land are important in the management of pulmonary manifestations of AS.