I've done several long races on no-carb or low-carb. I found often that I wasn't really sore the next day. But I ran these races much slower than when I was living the hi-carb life. My guess is running slow doesn't stress the muscles the way running fast will.

The 100 mile run I mentioned earlier turned into a 50 mile shuffle. Early on I had stomach problems and wasn't able to eat or drink much of anything. By the 50 mile point I had severe stomach pain and opted to quit. The pain seemed to get worse over the next week. I went to the doc who diagnosed an ulcer.