Recovery runs in sub-3 training: vital or junk miles?

Some runners sneer at recovery runs, as if anything slow is a sign of weakness or wasted effort. For the sub-3 runner, though, nothing could be further from the truth. Easy miles are not junk - they are one of the hidden engines of endurance.

When you run slowly after a harder session, you are not just passing time. Blood flow to the muscles increases, helping to clear the by-products of intense effort. The gentle impact keeps tendons and ligaments supple. At a cellular level, these runs stimulate adaptations that strengthen your aerobic base - the bedrock of marathon performance. Slow running also helps regulate inflammation and encourages the repair processes that allow the body to recover from harder training. Far from “wasting” energy, you are investing in your next big workout.

The 80:20 rule, popularised by Matt Fitzgerald, captures this perfectly: around 80 percent of training should be at low intensity, with only 20 percent spent pushing hard. It sounds counterintuitive, but running slower more often is one of the surest ways to run faster when it matters.

And what of the dreaded “junk miles”? The term makes easy running sound pointless - empty effort, logged for the sake of appearances. In reality, even a very short recovery jog can have value. A gentle 3km outing after a hard session improves circulation, reduces stiffness and keeps the body moving through fatigue rather than stagnating in it. I have often laced up a few hours after a brutal interval session for a slow 4km shuffle around the block, legs heavy and pace laughably slow. I also run 8km to and from work with a commuting backpack on. By the end I have almost always felt looser, fresher and better prepared for what comes next.

There is also the question of volume. If you only ever run “quality” sessions - intervals, tempos and long runs - chances are you will struggle to accumulate the weekly mileage needed to build real marathon fitness. Worse, you risk training in only a narrow set of gears, leaving important gaps in your development. Recovery runs are how serious marathoners - indeed even the elites - build resilience, consistency and aerobic depth without constantly overstressing the body.

So call them what you like. But for the serious marathoner, recovery runs are not indulgent luxuries - they are a vital part of the process. The hard sessions provide the stimulus, but recovery running is what allows you to absorb it and build a solid aerobic base. Strip those easy miles away and training quickly becomes brittle, inconsistent and far harder to sustain. Embrace them properly and they quietly make everything else possible.