First reply on getbig....As we all know soreness (not pain or injury) is the best sign that a BB has trained a muscle group correctly. As a matter of fact if this doesn´t occur, in my personal experience, one has done very little but maintainence. In theory and historically the muscle tissue should not be trained when still sore as this is counter productive, the muscle tissue is in the reconstruction process. But once again in my experience I have seen that the human body is a machine that adapts quickly, especially to training. Thus, shocking the muscle is one of my favorite training principles especially for lagging body parts. So either way, resting the tri or training it you will get results.