Misunderstood: The Recovery Run

Yesterday I ran what felt like a pretty tough 15.2 miler. Probably what made it feel so tough is the fact that my legs are still recovering from Sunday's half-marathon. Needless to say, I was happy to have a simple 5 mile recovery run on tap this morning. As far back as I can remember, "recovery runs" have been a part of my training schedule. For those non-runners out there, a recovery run is a relatively short, slow run done after a harder run (like a speed workout or a long run). Sometimes they're done the following day, sometimes they're done only a matter of hours after the hard workout.

These shoes look pretty beat up. I bet they could use a recovery run.

The old school explanation for recovery runs is something like this:

The recovery run will help you to recover faster by increasing blood flow which brings recovery aid in the form of oxygen, clearing away lactic acid, and helping you replenish your glycogen stores.

These days, most experts say that recovery runs do not help you recovery faster. According to running guru Matt Fitzgerald, lactic acid levels return to normal within an hour after even the toughest workouts and lactic acid isn't even the cause of muscle fatigue.  There also is no scientific evidence that light activity like a recovery run promotes muscle tissue repair, glycogen replenishment, or any other physiological response that actually speeds muscle recovery. 

So why bother with recovery runs?  They're not junk workouts, they actually help you work on two things: overall mileage and running on tired legs. First, speaking to mileage, or training volume, the benefit is easy to explain: within your own physical limits, the more running you do, the fitter you become, even if your workouts are relatively easy. Recovery runs also help you to work on your running economy because you do the run in a pre-fatigued state without creating enough additional stress to necessitate more recovery time.

I wish someone had explained the logic behind these runs to me in the beginning because it can be difficult forcing yourself to run slower than usual, but there you have. Recovery runs are a valuable part of any training regime, even if it's not for the reasons you may have thought.