Take planned rest days when you are healthy, or you will be taking forced rest days when you are injured.
Injuries are the Trojan Horses of trail running. Like in the city of Troy, everything in your body can seem fine, until things suddenly become very, very bad. And in both scenarios, without vigilance, things will not end well for any Achilles involved.
As a coach, my main goal is to keep motivated runners healthy. While hard training is a prerequisite to create elite athletes, adequate recovery is essential to keep them from destroying themselves through injury and physiological breakdown.
The dilemma is palpable. Miles make the runner; miles injure the runner; injuries unmake the runner. My solution for the trail runners I coach (from professionals to those just getting started) is to use both full rest days and recovery-run days to structure training. Here is how to think about rest and recovery.
Breakdown and Recovery
First, the basics: Running training causes breakdown all the way from the cellular level to physiological systems that involve muscles, organs and even the brain. Train hard more than a few days in a row and (barring freakish recovery powers) the breakdown will build until performance falls off a cliff and training becomes actively counterproductive. Overtraining and overuse injuries are the result.
That same stress that breaks you down, however, is also what builds you up. Adequate rest and recovery allows the body to adapt to minor breakdown to come back stronger than before—that’s what leads to fitness gains. Recover smart and you’ll be like a real-life Million Dollar Woman or Man, but in much shorter shorts.
The Role of Impact Forces
Why is running different? Unlike endurance sports like cycling or swimming, running involves impact forces. These impact forces increase breakdown, thus decreasing the total amount of work you can do before getting injured. That is why top runners train at most 14 hours per week, while the top cyclists and swimmers can train twice as much. (Don’t even get me started on how much triathletes can train.)
Impact forces are the reason rest days are important for most runners. Most impact-related injuries develop over time, but once they reach a tipping point, they often manifest themselves rather quickly. Rest days—when used strategically over the course of a training cycle—can heal budding injuries before you even know they exist.
Recovery Runs vs. Rest Days
Some serious runners prefer to rely solely on “recovery” days, substituting slower runs at anywhere from 50 to 75 percent of maximum heart rate for true days off.
Recovery runs can actually accelerate the recovery process by increasing blood flow, plus they have some aerobic benefit. (A general guideline for recovery is to run at around marathon pace plus one minute, though closer to marathon pace if you are newer to running. These runs are not necessarily slow—when you are fit, they can even become somewhat fast, especially near the end.)
However, while they are mostly positive, recovery runs still involve impact forces to stressed bones, joints, tendons and ligaments. Even the slowest recovery pace can exacerbate a stress fracture. So while rest days may be worse from a pure performance perspective (and from a how-much-pizza-you-can eat-for-lunch perspective), any gains from recovery runs can be rendered moot by being injured for weeks or months.
Using Rest and Recovery Days
Recovery Run Frequency: The frequency of recovery runs depends on how much you are running to begin with. I recommend doing at least four or five total runs a week no matter what your level. Spreading out your total distance over the course of a week decreases injury risk and allows your body to stay adapted to the impact forces.
In addition, you should never do harder efforts two days in a row unless you are an experienced runner working from a smart plan. So, if you are running five days a week, three should be recovery runs. If you are running six days a week, three or four should be recovery runs. And if you are running seven days a week, three to five should be recovery runs.
Rest Day Frequency: Here things go from a science to an art. Some runners can get by without ever taking a rest day. However, if you are reading this article for training advice, then you are unlikely to fall into the never-rest, never-injured category. These folks are freaks, and I mean that in the most awestruck way possible.
For all of the experienced runners I coach, there is a complete rest day every seven to 10 days. In general, Mondays work best, as they follow longer, harder trail runs on the weekend. (That also allows you to catch up on all the work you will miss for the remainder of the week while you’re updating your Instagram with photos from your morning trail run.)
For less experienced or injury-prone runners, two rest days a week might be needed. Another option is to replace one of those rest days with a “shuffle”—a run that minimizes impact forces by being deliberately slow (at least two minutes per mile slower than marathon pace).
Finally, any more than two rest days per week is generally not advisable unless you are new to running, a multi-sport athlete or over 50 years old—packing too much mileage into too few runs can increase injury risk. Focus on frequency and consistency for long-term success.
On rest days, don’t vegetate like a human eggplant. Instead, walk around, foam roll, do some strength and mobility work (though no leg weight-lifting), and spin on the bike if you want. Just be sure to avoid impact forces (that includes things like CrossFit, tennis and jumping up and down on the bed).
Remember the importance of rest days, and you can make recovery (and your running performance) great again.
David Roche is a two-time USATF trail national champion, the 2014 U.S. Sub-Ultra Trail Runner of the Year and a member of Nike Trail Elite and Team Clif Bar. He works with runners of all abilities through his coaching service, Some Work, All Play. Follow David’s daily training on Strava here, and follow him on Twitter here.