it is great that you have had exellent results from your surgical procedures. you are wise to try to get moving and active again. being fit and active is the best thing that you can do to prevent future problems with your back. however it is important that you develop a progressive aerobic and strengthening regimen. i would suggest that you contact your surgeon for a referral to a spine physical therapist who can help you get started on your return to exercise. in general you want to avoid impact type exercises so the elliptical is a reasonable option. you should also avoid any heavy weights particularly free weights above your head that will cause compression to the spine. i usually recommend that spine patients use the weight machines that use resistence mechanisms or weights on tracks with pulleys. these are less likey to injury you. you also need to do regular core muscle strengthening. again a physical therapist can help you get started. pilates is the commercial exercise course that is most similar to a core strengthening program.
i have had two back surgeries and am pain-free except for some stiffness. what exercises can i do to play tennis again?