We will study 20 participants with active axSpA who are about to start biologic therapy as part of routine care. In brief, we will carry out the following assessments before and after
therapy- MRI of spine and SI joints - mSASSS scoring
- Record standard PROs: BASDAI, BASG, BASMI, BASFI, ASDAS, ASAS-HI, EQ5D-3L, WPAI, SQUASH,
- ESR, CRP
- IMU sensor tests in clinic for ROM in cervical, thoracic and lumbar spine.
- IMU sensor tests at home for standardised function testing

