Think that one quite common especially those from NS and reservist days. Common injuries are the knee and back.
Not sure about others, but think cannot quite fully recovered once kanna before. Cause (for lack of better words) got weak spot already. Some may observed that the pain might come back once in a long while when strain too much.
Can only take more care when bending over for long and/or carry heavy weight. Not careful the pain can easily come back. One way it helps alot is to slowly strengthen the back muscle so that better able to support. Won't feel that easily strain.