The Effects of Pilates Exercise Training Combined with Walking on Cardiorespiratory Fitness, Functional Capacity, and Disease Activity in Patients with Non-Radiologically Confirmed Axial Spondylitis

The objective of the study was to examine the effects of Pilates exercise training combined with walking on cardiorespiratory fitness, functional capacity, and disease activity in patients with non-radiologically confirmed axial spondylitis (nr-axSpA). Thirty patients with nr-axSpA (seven women (90%), with a mean age of 46.07 ± 10.48 years old and C-reactive protein (CRP) 2.26 ± 2.14 mg/L) were randomly divided into two groups: A (n(1) = 15 patients) and B (n(2) = 15 patients). Group A followed a 6-month home-based Pilates exercise training program, while Group B remained untrained until the end of the study. A cardiopulmonary exercise test (CPET), timed up and go test (TUG), five times sit-to-stand test (5×STS), sit-and-reach test (SR), back scratch test for the right (BSR) and the left arm (BSL), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), and Ankylosing Spondylitis Disease Activity Score (ASDAS) were applied to all patients, both at the beginning and at the end of the study. After 6 months, Group A showed higher values in exercise time by 37.41% (p = 0.001), higher peak oxygen uptake (VO(2)peak) by 25.41% (p = 0.01), a higher ratio between oxygen uptake and maximum heart rate (VO(2)/HRmax) by 14.83% (p = 0.04), and higher SR by 18.70% (p = 0.007), while lower values were observed in TUG by 24.32% (p = 0.001), 5×STS by 12.13% (p = 0.001), BASDAI score by 20.00% (p = 0.04) and ASDAS score by 23.41% (p = 0.03), compared to Group B. Furthermore, linear regression analysis showed a positive correlation in Group A between BASDAI and 5×STS (r = 0.584, p = 0.02), BASDAI and TUG (r = 0.538, p = 0.03), and ASDAS and 5×STS (r = 0.538, p = 0.03), while a negative correlation was found between BASDAI and VO(2)peak (r = −0.782, p < 0.001), ASDAS and SR (r = −0.548, p = 0.03), and ASDAS and VO(2)peak (r = −0.659, p = 0.008). To sum up, cardiorespiratory fitness, functional capacity, and disease activity improved after a long-term Pilates exercise training program in patients with nr-axSpA.