The Case for Moderately Challenging Runs
Sometimes the best run is somewhere between hard and easy. Here are three uses for moderate runs, and three examples to try.

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Among the more tried-and-true principles of run training is the so-called Hard/Easy Rule. This rule stipulates that every hard run should be followed by one or two easy days consisting of easy running, gentle cross-training, or rest. It’s a solid rule that I fully endorse, but I have one small problem with it, which is that it falsely conveys the notion that training should always be either hard or easy and never anything in between, which isn’t true. I believe there’s a place in the training process for moderately challenging runs, and I’m going to make the case for them here.
It’s quite simple, really. A perfect training program is one that subjects a runner to workloads that are high enough to maximize fitness gains but not so high as to result in injury or burnout. In other words, the workload needs to stay within a Goldilocks Zone between too light and too heavy. That’s hard to do if all of your runs are either very easy or quite challenging. Sprinkling some moderately challenging runs into your training will help you fine-tune your workload, bringing it closer to perfect than you can get it with hard and easy runs only.
I’ve found three specific uses for moderately challenging runs that offer the greatest benefit. When you haven’t done a particular type of workout in a while — say, hill repetitions or marathon-pace running — it’s best to reintroduce it with a moderately challenging version of that type of workout rather than a highly challenging version. That’s one use.
A second use: Certain moderately challenging runs also work well the day after an easy run and the day before a hard run. For example, if you routinely do hard runs on Tuesday and Friday, you might do an easy run on Wednesday and a moderately challenging run on Thursday.
A third use for moderately challenging runs is to provide a maintenance-level training stimulus when your primary focus is maximizing a different component of your fitness for an upcoming race. For example, suppose you have a marathon coming up in a few weeks. In this case, you’ll want your hardest runs to be long runs and workouts done at or near your marathon pace. But you’ll still want to maintain your speed, and you can do so without interfering with your main focus by doing moderately-challenging speed workouts.
Here are three moderately-challenging runs to try in one of these settings:
Hitomi’s Pace Run
Japanese runner Hitomi Niiya holds her country’s national record for the half marathon, having clocked a time of 1:06:38 in winning the 2020 Aramco Houston Half Marathon. One of the staples of her training regimen is a weekly “pace run,” which is best described as a brisk easy run. In a typical pace run, Niiya covers 12 km (7.44 miles) at an average pace of 5:50 per mile, which is 45 seconds per mile slower than her record-setting half-marathon pace.

In physiological terms, Niiya’s pace-run pace falls right at the ventilatory threshold (VT), which, as the effort level where you have to start breathing harder, marks the boundary between low intensity and moderate. Although it’s best that runners do most of their easy runs well below the VT, intentionally riding the line between low and moderate intensities once a week enables Niiya to maximize the benefits of easy running without going overboard.
It’s important to point out that the vast majority of nonelite runners unwittingly do most of their easy running slightly above (harder than) the VT, which is counterproductive, so you’ll only want to introduce pace runs into your training if you’ve already corrected this common mistake. Determining your VT pace with exactitude requires formal testing, but you can get pretty close to it by aiming for a perceived effort rating of 4 to 4.5 on a 1-10 scale. As for distance, your pace runs should be toward the longer end of your normal easy-run distance range. Give yourself a few minutes to ease into the session at the beginning, then lock into your VT pace and hold it the rest of the way.
Ben’s Leg-Speed Fartlek
Unless you’re focused on race events of 5 km in distance and below, speed work should occupy a relatively small space in your training at most times. In the summer of 2017, when I trained with the NAZ Elite professional running team in Flagstaff, Arizona, Coach Ben Rosario taught me the following workout, a moderately challenging fartlek run that he uses to maintain speed in his athletes when they’re focused on longer events. Although it’s quite simple in format, I find it to be a lot of fun because it offers the exhilaration of running fast without the discomfort of running fast to the point of significant fatigue.
Start with 10 to 20 minutes of easy jogging and then do a few form drills (e.g., high knees, butt kicks) to get your legs ready to go fast. The fartlek portion of the run consists of ten relaxed sprints of 20 seconds with each sprint followed by one to two minutes (the exact amount of time isn’t important) of easy jogging. Aim for a speed that’s roughly 90 percent of your personal limit and concentrate on staying relaxed while still moving fast. Cool down with another 10 to 20 minutes of easy jogging.
Kenyan “Easy” Run
Kenya’s elite runners are famous for starting their easy runs at a crawl and finishing them at a sprint (slight exaggeration). In other places this format is known as a progression run, but no matter what you call it, it’s a good way to get in a moderate training stimulus. The key to preventing your Kenyan-style easy runs from becoming more challenging than you intend is to run by feel and make sure you don’t stray outside your comfort zone at any point. It’s okay to run hard toward the end, because running hard for short durations is comfortable, but unless you backload your pace progression you’re likely to find yourself running too hard too early.

Use these perceived effort guidelines to keep on track:
% of Run Completed | 0 | 20 | 40 | 60 | 80 | 90 |
Perceived Effort Rating | 2 | 3 | 4 | 5 | 6 | 7 |
Kenyan easy runs work especially well when inserted between a normal easy run and a hard workout.