The appropriate or acceptable pace to run at on easy runs is a topic often debated by distance runners and coaches and usually with a wide variety of opinions. So I wanted to weigh in on the topic here on my blog. As with most things in running, I try to approached the topic with a logical analysis; breaking things down into its elemental parts, defining what the goal is, and then deciding on how best these parts can be used to accomplish this goal. What I am presenting here is my interpretation of each of these things (rarely is it 100% black and white).
The goal of an easy/recovery run is to recover from a stress workout, while maintaining or advancing our general aerobic fitness and cellular adaptations to running. Easy/Recovery runs are a key part of the stress and recovery principle, which states that we must stress a body in a certain discipline (running) and then allow the body to recover, and once it has recovered it will be better adapted to the stress than it was before (fitter). (see illustration above) I call one complete stress and recover cycle a “base unit” in our training. The easy run is an integral component of the base unit, as this is where the super compensation occurs.
Given this goal, the question becomes how much and at what pace should our easy running be in order to recover and gain the super-compensation benefits, while still maintaining or advancing our aerobic fitness and adaptations.
The answer to that question will depend largely on how hard the stress portion of the base unit was, and how long we have to recover before our next stress workout. The answer would likely be different if we have 3 days between stress workouts than it would be if we have to have just 1 day between workouts. But not so much the pace of the easy runs, but rather the duration of them, as I will explain in a minute.
The Elemental Parts
How much work/effort we do in any run is a product of multiple factors including the duration of the run, the pace we run, the course we run on and the weather condition. In this analysis I hold the other elements constant so I can focus on the duration and speed components of this equation.
To give us units to work with let’s use minutes of running for the duration, and for the pace let’s use a percentage of lactate threshold pace. (I define lactate threshold pace as roughly the pace we can hold for 60 minutes in an all-out race effort).
Both speed and pace are critical in our analysis. 60 minutes at 75% of lactate threshold (LT) pace is a greater overall effort than 30 minutes at 75% of lactate threshold pace; likewise 60 minutes at 85% of lactate threshold pace would be a greater effort than 60 minutes at 70% of lactate threshold pace. So we must consider both in reaching our goal.
In the book “Daniels’ Running Formula”, Dr. Jack Daniels develops a chart that assigns a single point value to each run based on the duration of the run and the relative pace of the run. If we determined that in order to recover from our last stress workout before our next one, that we could only do a run of 20 point in value on Dr. Daniels’ chart, then there would be multiple ways to get those 20 point. We could run a shorter duration at a faster pace or we could run for longer but at a slower pace. In theory either way would produce the recovery desired.
So then one might state, “so it doesn't matter how slow or fast I run then right, as long as I adjust my duration to match”. My answer to that would be “only within a certain range”. Here is why:
If we run too fast on the run (faster than a certain point) we begin substantially stressing certain systems of the body that we want to be recovering from the previous stress, not stressing again. This manifests itself by reduced performance on our stress workout days and a feeling of not being recovered from our last stress workout.
The slower we run, the less muscles fibers that are actively being used and the less bio-mechanically efficient we run. So if we run too slow on the easy run (slower than a certain point) we may be teaching our body bad bio-mechanical habits, and even worse, doing so for an extended period of time. We run fast intervals at times on our stress days to teach our body to operate more efficiently/economically, but similarly if we subject our body to prolonged periods at paces that are too slow, we can teach it to be inefficient and bio-mechanically uneconomical. This manifests itself not on our slow days (which are easy) but through being more injury prone on our stress days and long runs, where our bio-mechanical bad habits become more dangerous. But because the injury or problem happens in a stress workout rather than easy run day, most runners and coaches fail to make the connection to their easy run paces.
So what we want to do is run our easy runs slow enough to let the necessary systems recover and fast enough not to teach our body bad bio-mechanical habits. So what is that appropriate easy pace range? I believe this range to be (and many other elite coaches and researchers seem to generally agree) between 20% and 30% slower than lactate threshold pace or roughly 65% to 75% of maximum heart rate (for those who use a HR monitor).
So if your lactate threshold pace is 6:00 per mile, than your easy runs would be best done at a pace of between 7:12 (6:00 + (6:00 x .20)) and 7:48 per mile (6:00 + (6:00 x .30)).
Note: These paces may need to be adjusted for weather and/or course conditions.
With this safe pace range set then, the variable we change is our duration in order to get the proper recovery needed. Gradually over time, as our fitness and capacity grows, we may be able to increase the duration of these easy runs. Easy pace can also progress to the extent our lactate threshold improves.
If in our training, we use a 3 day base unit: a stress day followed by 2 easy run days as recovery, at the beginning of the training cycle we may determine that we can run for 50-60 minutes in our easy run pace range (20-30% slower than LT pace) and be properly recovered for the next stress workout. Gradually during the course of the cycle or over the course of the year, this duration may increase, to say 60-80 minutes, as our work capacity grows.
Common Mistakes (IMHO)
One mistake (in my opinion) that I often see runners make is they determine the distance they want to do on a recovery day first and then adjust the pace accordingly. This happens often with marathoners who want to increase mileage too quickly. This leaves them susceptible to running too slow (teaching the body bad bio-mechanics) if they pick a distance that doesn't allow them to stay in the easy pace range I have outlined. These runners feel great about getting in the extra distance, but run the increased risk of injuries from running for prolonged periods in an inefficient manner.
I suggest that instead they should determine the appropriate easy pace (20-30% slower than LT pace) and then see how much distance/duration they can cover at that pace range and still adequately recover, and start there and try and grow that as their fitness improves.
Another mistake I often see is, runners running outside of their appropriate easy pace range on their easy days, in order to run with runners who are faster than they are. This often results in the runner not adequately recovering from the last stress workout and thus not getting the full super-compensation (bump in fitness) they should/could be getting from the work they did.
While I know it’s tempting to run with faster runners on a day when it’s possible to keep up with them, but good and effective training requires adhering to the principles of stress and recovery. Luckily the easy pace range is larger than most hard training paces, so this does allow for some runners of slightly different fitness levels to run together at a pace within both of their easy pace ranges, but runners should be careful not to stray too far outside their peer group on recovery runs.
Coach Mark Hadley
Coach Mark Hadley