If training for your first marathon, or even if you’re generally not used to regular runs longer than 2 hours… there’s a better way to get in long run mileage than just doing one long uninterrupted run.
Once a single run exceeds 2.5 hours, the physical damage a run does can offset a lot of the training benefits from running long. Many runners may need multiple easy days or days off to recover, which derails some key workouts and disrupts your fitness development more than the long run helped it.
The Galloway Method, aka run/walking your longest workouts, offsets this by building in repeated rest breaks through walking. However, training this way only makes sense if you intend to run/walk the marathon. If so, then Galloway’s approach or any run/walk variation is completely fine.
For those who intend to *run* the entire race, you need to fully run all your long runs. And you need to be mindful on long runs of the 2.5 hour threshold.
Yes, that means your uninterrupted long runs will be well short of many training thresholds like the 20 Mile long run.
But that doesn’t mean you can’t or shouldn’t run 14-20+ miles on long run training days. In fact, when new to marathons, you absolutely need to get these long mileage days in.
So how do you do it, if you should only run 2.5 hours max, and you can’t possibly cover the needed distance in 2.5 hours at an easy, sustainable pace?