According to most experts, there are four essential elements for marathon training: endurance, strength, speed, and stamina. Endurance is the training base of distance, distance, and more distance. Strength is the added dimension of anaerobic athleticism. Speed is, of course, the rapidity of stride turnover. Stamina is the ability to maintain that stride turnover for extended periods of time.
Good form in preparing for a marathon demands different types of workouts for each of these essential elements. In other words, it is not enough to simply "run a lot."
The problem is that busy schedules tend to mitigate against anything and everything except sporadic road work. And that makes for bad marathoning.
Unable to focus on any of the four essentials, at least I got in three lackadaisical miles today.