Myth # 1: Your body will feel great. Where does this myth come from? Mostly, wishful thinking. Even seasoned marathoners fall victim to this myth until they start to feel subtle or new aches and pains. The truth, you body is healing--not healed.
Myth # 2: You will feel good on all of your taper runs. Where does this myth come from? The idea that after your last long run during the training schedule your body knows it is at taper and therefore, because you leg muscles somehow know that you will be decreasing your mileage, they automatically feel better. This happens to me every time. I use a three week taper (going down from 23M to 13M to 9M and then 26.2M). And still, even after my 13M long run I have difficult runs during the week. I'm not saying I'm going crazy with my mid-week runs. Nope, doing the same thing I always do. But still, sometimes they suck. The truth is that this happens all the time during my training. But I never notice or care because I'm not on taper. I get taper blindness and forget how taxing training is on my body.
Myth # 3: Let me know one you have noticed.
*At least, as experienced by me.