Thank you for your question. There is really no zero chance or guarantees but in my practice, my patients are able to resume unrestricted activity 8 weeks after a tummy tuck. Be sure to consult with an experienced board certified plastic surgeon. Good luck!
Given that you have had a tummy tuck, the muscular plication is assumed to be well healed at 6-8 weeks. Your request for a time of "zero chance of injury" does not really exists, however. Given the normal workout and physical activity of patients, you can expect to be able to do your normal activities at about 8 weeks. You may feel some residual stretching after that, however. To prevent injury, ease into physical actives and listen to your body. If your abdominal muscle hurt, decrease the work on them and gradually increase your activity as tolerated.