When your dog is around 18-months-old and done developing, it’s a good time to start taking him out to jog with you. Some vets say you can do it at the one-year mark, but larger dogs like Boxers can still have bone formation developing a bit longer than a year. So it’s always best to be safe. While your pet is younger, I’d let him run at his own pace with you on grass or dirt or at the beach during play sessions, but I would not take him on an actual jog with you until the 18-month mark.