Yes, I feel that training everybody party twice a week is overtraining. I only train my abs and calves twice a week because they heal quickly. I hit every muscle once a week except calves and abs. I go all out on my workouts. I lift with heavy weight and go to failure on every set. I even do a couple forced reps. Thus I am sore for the next couple of days. Some people do hit each muscle twice a week and have good results, whereas others do it once a week like myself. I would recommend once a week, but I would do whatever works for you.