Question for marathoners or half marathoners

It doesn't have to be done without stopping, especially on the longer days. Your body will tell you when it needs to rest. I often take 5 minute breaks on long training runs to catch my breath or take in some fluids.

Think of those online training programs as a guide, not an exact formula. They key is usually to do a once-a-week long slow run of gradually increasing distance, working toward the length of the race. The other runs should be shorter and a bit faster, but the exact distance, or whether you do 2/3/4 of them during the week really doesn't matter that much.