What activities should i avoid after spinal fusion surgery?

Assuming that you : Are fully healed and rehabilitated you should try to avoid any activities that involve combined repetitive flexion and rotation like racquet sports and golf. Heavy contact sports are not advisable like rugby or tackle football . If asking in post op period, this is dependent on type and extent of fusion as well as your health/ conditioning including your diagnosis----your surgeon will guide you.

Depends...: This really depends on where in the spine your fusion is (cervical, thoracic, lumbar), how many levels were done, how long ago your procedure was, and if you have fully fused based on imaging.