easy runs

The Science of Easy Runs

Easy runs are more than just a complement to your key workouts. They are potent workouts in their own right and enable you to move up the performance ladder. 

“Easy runs can make or break a training plan.”

Getting the intensity, duration, and number of training days of your easy runs right can be a challenge. It’s a balancing act—a crucial part of training that affects all your key workouts.  

The Benefits of Easy Runs

Before we zoom in on easy runs, let’s look at the broader picture of easy mileage. While your training plan may include as few as 1 or 2 dedicated easy runs per week, at least 80 percent of your weekly mileage should be run at an easy pace. This includes your long run—at least the lion’s share—and all warm-ups and cool-downs—even rest intervals, to be exact. 

So why 80 percent of easy running if interval or tempo training is more effective per time unit?

For one, you won’t be able to handle much training at higher intensities if you haven’t established a large base at lower intensities. Elite runners can absorb an enormous amount of training at intensities at or above the lactate threshold precisely because they cushion it with 100 miles per week of easy running.

Secondly, easy mileage is low stress on your nervous system, muscles, connective tissues, and your endocrine system. The training effect may be low to moderate per time unit, but the absolute training effect is significant as the hours accumulate. Besides, who wants to turn up 5 days a week on a running track blasting 800m intervals even if that was feasible and saved time?!

How Many Easy Runs per Week?

Now, let’s look at the structure of a typical training week for runners. The most common approach is three key workouts: an interval session, a tempo run, and a long run on weekends. There may be variations according to race distance and training phase, but overall, that formula has stood the test of time. For that, you need at least one easy run midweek to create balance.

Here’s a glance at the most common training frequencies:

3 runs per week… Consider stepping up to at least 4 runs per week unless you are a beginner.

4 runs per week represent the minimum number of running days if you’re more than just a jogger. A 4-day running week can get you far, but it maxes out at an 8-mile easy run and a 12-mile run on weekends, give or take a mile or two. That makes it a 30 – 35 mile training week, at most, including the two quality workouts.

5 runs per week either make a 4-day training week easier by spreading out the mileage or enable you to add extra mileage. In this case, you’d have 2 dedicated easy runs, 2 quality runs, and the long run. That also leaves you 2 days a week to cross-train or engage in strength training at the gym if you so desire. 

6 or 7 runs per week is typically the domain of the advanced runner. Not only do you gain the mileage of a 3rd or 4th easy run, but you can also increase the duration of each and every run that way, including the key workouts themselves. 

That said, it’s not necessarily the number of running days that defines your level as a runner. There are “100-day challenge” joggers who happily run 3 – 5 miles per day without structure and there are serious front-pack amateur runners on 4-day running weeks guided by a solid training plan.

How Long Are Easy Runs?

An easy run is generally 30 – 75 minutes in duration. Running shorter than 30 minutes isn’t enough to have much of a training effect unless you’re an absolute beginner. Runs above 75 minutes, in contrast, no longer constitute an easy effort. That’s where long runs begin for us mortals. 

Running “doubles” is a way to increase easy mileage without making single bouts too stressful. For example, you could split an 8-mile easy run into 2 runs, not necessarily evenly. If you are an advanced runner, you could run a shorter easy run in the morning on a day when you have a faster workout in the afternoon. 

A close cousin of the easy run is the recovery run. Some coaches use the terms easy run and recovery run interchangeably. By my definition, a recovery run is just another easy run that is no longer than 45 minutes and at the lower end of the easy run pace range. They are often run the day after hard workouts.

What is the Intensity of Easy Runs?

When it comes to the intensity of easy runs, most runners commit the grave mistake of running them too fast. “No pain, no gain” may be good advice if you’re pushing that extra rep at your gym’s bench press, but it’s a fool’s errand for your easy runs. 

Sure, any run at a faster intensity has a higher training effect. But this comes with a higher recovery cost. Zoom out and look at your training for the entire week. There, your easy runs live next to VO2 max intervals, tempo runs, and long runs—which are the workouts that are exponentially more effective. And those who run their easy runs too fast are the ones who can’t run their key workouts hard enough. They’re in for a massive net loss.

The main purpose of easy runs is to single out your slow-twitch muscle fibers. Give your fast-twitch fibers a break to be ready to do the work when it counts. Instead of running easy runs faster, increase their duration. In some circumstances, it makes sense to substitute an easy run with a run at the aerobic threshold. But this should be the exception rather than the rule.

But is there such a thing as running an easy run too slow? I believe there is. Your heart gets a full contraction only above 60% of your heart rate reserve (HRR). A full contraction of your heart throughout an easy run is a powerful trigger for increased stroke volume, directly influencing VO2 max.

Monitoring by Heart Rate vs Pace

Both heart rate and pace are well-established methods of monitoring intensity for easy runs. I have both metrics on my running watch’s display. While I prefer exact paces for all runs faster than my lactate threshold, I go with heart rate for my easy runs. If you are running on hilly terrain, in a tropical climate, or in windy conditions, your pace doesn’t accurately reflect the desired intensity of your run. In those instances, you should rely exclusively on your heart rate monitor. 

The 2 methods of determining your heart rate zones are % of HRmax and % of HRR. Calculating your HRmax (percentage of your maximal heart rate) is a no-brainer. However, the second method, the HRR method (percentage of heart rate reserve) is preferred. In addition to your maximal heart rate, it also takes your resting heart rate, and hence your fitness level into account. 

This is calculated with the Karvonen Formula: Target Heart Rate = % intensity x (HRmax – HR rest) + HR rest. Let’s assume you have an HRmax of 185 and an HRrest of 45 and you want to run at 65% of your HRR. That makes it 0.65 x (185 – 45) + 45 = 136 bpm target heart rate. 60 – 70 % would come out as an easy zone of 129 – 143 bpm. 

Most advanced running watches can be set to HRR, so the calculations are done for you.  Of course, you can also run by feel, although this is something I only recommend to very experienced runners.

Add Hill Sprints

I believe all runners should add short hill sprints after one or two of their easy runs. Start with a 1x 50m repetition and add 1 repetition each week until you reach 4 to 6 reps. Consider it twice a week during the base period of your training plan and maintain it once a week in the following training phases. 

This is the most running-specific strength training you can do. What’s remarkable about hill sprints is that they recruit maximum muscle fibers while impact forces are comparatively low. Not only will this add power to your stride, but it will also make you a more injury-resilient runner. But stick to a 6 – 8 percent grade. Above that, your running form changes too much to reap the full benefits.  

4 weeks from race day, I recommend you switch to 50 – 100m sprints on flat terrain. That results in a faster leg turnover and is, therefore, more race-specific. You’ll thank me for it on race day, especially if you manage to outkick a few competitors in the final meters of a cheering crowd.

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Sandro-Sket-4 (2)

Sandro Sket, CSCS

Certified Strength & Conditioning Specialist

Hi, I’m Sandro. A lifelong endurance athlete,
coach, and founder of RunningFront.
You can find my training plans on
TrainingPeaks and FinalSurge

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