Selection and inclusion of patients will be done by principal investigator of Rheumatology Department. After verification of inclusion and non-inclusion criteria by principal investigator and signature of consent, patients will be randomized by 1: 1 randomization (centralized randomization by statistician into 2 groups at M0). They will participate in sessions in a deferred manner due to two per week for each group:~Interventional A group: 32 sessions (on average 2/week) performed from M0 to M4 in 15 patients.~Control B group: 16 sessions (on average 2/week) performed from M2 to M4 in 15 patients.~Patients of B group will be not performing sessions with A group patients. Sessions lasting about 45 minutes will be proposed from Monday to Friday in a room planned from this activity within the CHU. Exercises will be adapted and personalized according to each one. Evaluations will be carried out at M0, M2 and at the end of the protocol at M4.~Assessment of pain and stress will be done before and after each session. Final assessment will be done at 4 months after randomization. Fitness assessment and tai chi sessions will be conducted by APA student.
Our hypothesis is that tai chi sessions would increase physical activity of patients with Spondyloarthitis. The main objective is to study the effect of tai chi sessions (16 vs.0) on global physical activity of Spondyloarthitis patients, compared to a control group without tai chi.