Why Do We Add Strides on Easy Days?
Isabella asked me this a few days ago, standing at the end of a grass field after an easy three miles, looking at me like I had asked her to do something pointless. She wanted to know why we bother tacking four fast pickups onto the end of a run that the whole point of was supposed to be easy. It is a fair question. It might be the best question a distance runner can ask, because it forces you to think about what easy running does and does not do.
Here is the short answer. Easy running builds the aerobic engine, but it lets the top end speed erode over time. Strides keep that top end speed available, sharpen your mechanics, and prime your nervous system, and they do all of it for almost nothing in fatigue cost. That’s a bargain. Tiny investment, real return.
This article walks through how and why that works, what the research and the best coaches in the sport say about it, how to actually run strides, and where they can go wrong. If you coach or run, by the end of this article you should be able to answer that girl’s question better than I did.
What a Stride Actually Is
Let us define terms before we go further, because the word gets thrown around loosely and the confusion causes real problems. Many parts of the country refer to these as “striders.” Which seems wrong to me, but I suppose they think the term “strides” sounds wrong too. I think of striders as a term for the people running the strides. But maybe that’s just me.
A stride is a short, controlled acceleration. You start at an easy jog, build smoothly over the first 25 to 30 meters until you reach a fast, but controlled, submaximal speed (90% of max), hold that for a few seconds, then decelerate smoothly. The whole thing lasts roughly 15 to 30 seconds and covers somewhere around 80 to 100 meters. The effort sits at about 85 to 95 percent, not full sprint speed. You should finish feeling like you could turn around and do another one right away. But don’t. Take a walk break back to the start. This isn’t a interval or rep workout.
The most important distinction is this. A stride is not a sprint. A sprint is an all out, maximum effort burst with no holding back. A stride is a controlled build to a high but submaximal speed, held briefly, then recovered from completely. Runners Connect defines the difference this way: a sprint is maximum effort, a stride is a controlled acceleration to a high speed you hold and then back off.
As I mentioned, you will hear coaches call them striders, accelerations, pickups, or stride outs. Same thing. The recovery between them is full. Walk back, and only go again when you feel fresh. If you are gasping between reps, you are running them too hard or resting too little, and you have turned a stride session into a speed workout you did not plan for.
The Physiology: Why Easy Running Alone Leaves a Gap
To understand why we add strides, you have to understand what easy running leaves out and how it can degrade your performance over time.
Your muscles contain different fiber types, recruited in a predictable order based on how much force a movement demands. Slow-twitch fibers have a low threshold for activation, so they fire first and handle low effort work. Fast-twitch fibers, the Type IIa and IIx fibers, sit behind larger motor nerves that require a much greater level of excitation before they switch on. They do not get recruited until the effort climbs from moderate to high. This is Henneman’s size principle, and it is not controversial or novel. The swim coaching literature lays it out cleanly: the motor nerve serving fast-twitch fibers requires far more excitation, so those fibers stay dormant until force demand approaches maximum.
Now look at what an easy run asks for. Conversational pace, low force demand, heart rate down. That run recruits almost exclusively your slow-twitch fibers. The fast-twitch fibers never get the memo. Day after day of easy mileage, and those high-threshold fibers go quiet. The way I explain it to my athletes: fast-twitch fibers, if not challenged, get lazy.
A stride is the nudge. It briefly raises force demand high enough to recruit those Type IIa and IIx fibers, reminding your nervous system how to call on them, without the metabolic cost of a real workout. An easy run recruits almost exclusively slow-twitch fibers, a few strides engage the fast-twitch fibers with very little strain on the system and requires no recovery period that bleeds into the next day.
There is a growing body of work treating this as its own training category. A 2025 paper in the Scientific Journal of Sport and Performance introduces what the author calls Neuromuscular Recruitment Runs, short sprint-based efforts designed to activate Type IIa and IIx fibers without inducing metabolic fatigue. The argument is that endurance training neglects the neuromuscular system in favor of aerobic and metabolic development, and that these short efforts add a fourth pillar, neuromuscular efficiency, alongside the traditional three of aerobic base, threshold, and VO2max.
That same paper makes a point every distance coach should sit with. Late in a hard race, what fails is often not your cardiovascular system but your mechanics. Stride length shrinks, cadence drops, posture collapses. The authors describe this as biomechanical breakdown reflecting neuromuscular underperformance, not cardio depletion. Strides, run consistently, are part of how you keep that breakdown from happening when it matters.
Economy, Not VO2max
Here is where strides earn their keep for distance runners, and where the benefit gets misunderstood.
Strides do very little for your VO2max. That is not what they are for. What they improve is running economy, which is how much oxygen you burn to hold a given pace. Two runners with identical VO2max numbers will race very differently if one is more economical, because the economical one spends less energy at the same speed.
Strides have only a minor effect on aerobic capacity, but they significantly affect velocity at VO2max, which factors in economy. The pace you can hold at your maximal aerobic capacity can improve even when the VO2max number itself does not move.
How do strides build economy? By practicing efficient mechanics at speed. Every stride is a rep of good form under load: relaxed shoulders, quick turnover, a tall posture leaning from the ankle rather than breaking at the hips. Think of strides as neuromuscular priming that reinforces efficient form and improves economy. You are not just waking up fibers, you are teaching them to fire in the right sequence, which Strength Running notes is what drills and fast running do that steady easy mileage does not. The supporting research is real. Turner and colleagues, in a study cited throughout the neuromuscular running literature, found sprint training in distance runners produced adaptations that improved both running economy and performance.
The mechanical benefit is also immediate. After an easy run the legs can feel heavy and stiff, locked into a short, plodding range of motion. Closing with a handful of strides stretches the muscles back out, opens the hips, and lengthens the stride. It’s a mechanical reset, a full range of motion and neural readiness coming back online.
What the Best Coaches Say
Strides sit at the center of the most respected training systems in the sport.
Jack Daniels, exercise physiologist and Olympic coach, built strides into his programs from the very first phase. In Phase I, the base building phase of Daniels’ Running Formula, the prescription is easy running plus strides several times a week, with light hills. In his marathon plans, Daniels has runners doing 6 to 10 strides on two of the easy days each week. Notice the placement. On easy days. By design. Daniels treats strides as the gentle on-ramp from pure aerobic work toward the faster running that comes later, and as the lowest-risk way to keep speed present year round.
The Lydiard tradition, which built the modern aerobic base philosophy, uses strides the same way during base periods to keep the neuromuscular system honest while the bulk of the work stays easy. Simple Endurance Coaching captures the logic well: because strides are short and low-fatigue, they are ideal during base training, delivering just enough high-intensity stimulus to prevent detraining at the top end while most mileage stays easy.
“Easy running builds the engine. Strides make sure you remember how to drive it.”
For high school coaches specifically, Coach Jay Johnson is about as direct as it gets. His view is that one of the biggest mistakes coaches make is not having athletes do strides on the first day of cross country practice. He frames strides as “revving the engine,” and he insists on a planned progression: over a few weeks you decide whether you add more strides, longer strides, faster strides, or some combination. He also names the fear that holds people back, the worry that running fast in the summer will cause a runner to peak too early, and he rejects it.
Ten minutes, twice a week, at a fatigue cost so low it does not touch the rest of the plan. That is the whole bargain.
Specific Use Scenarios
Strides are flexible, and where you place them changes what they do. Here are the situations I use them in.
End of an easy run, base phase. This is the bread and butter, and the answer to the question in the title. Finish your easy run, then run 4 to 8 strides on a safe, flat, soft surface. This injects a small dose of speed into an otherwise aerobic day, keeps fast-twitch fibers awake, and does it without compromising the recovery purpose of the run. I like to have my runners do this without shoes to allow the foot to stretch, to make the gait more natural, and to avoid heel striking in favor of a mid-foot landing.
The day before a workout or race. Adding 4 to 8 strides to an easy run the day before a quality session primes the legs so the first hard rep does not feel stale. Many training plans pair 20 to 25 minutes of easy running with a few strides the day before a race so the runner does not feel flat on the line. It helps retain the elasticity and ‘snap’ needed to feel fast.
As a warmup primer before hard running. Here strides serve a different master. After 10 to 15 minutes of easy jogging, dynamic stretches, and drills, two to four strides rev the system so the body is genuinely ready to run fast. I have my distance runners do strides at the end of every race-day warmup, especially before shorter, faster races. The COROS staff make the mindset point I repeat to nervous athletes: that stale, harder-than-it-should-be feeling on the first rep usually comes from not being properly warmed up.
Race prep late in a season. Short strides at race pace a couple of days out remind the legs of the speed they will need without accumulating fatigue. The point is sharpness, and you keep them genuinely short and controlled.
Recovery and Warmup Variations
The how matters as much as the when. A few variations worth knowing.
Recovery between reps. For the neuromuscular and economy benefit, take full recovery. Walk back to the start, rest at least two to three times the duration of the stride, and start each rep fresh. Do not bunch them into one continuous fast effort. The moment recovery shrinks and reps start running together, you have changed the stimulus from neuromuscular priming to anaerobic work, which is a different day with different fatigue.
Warmup-priming variation. When strides are the bridge into a hard session, do fewer of them, two to four, and treat them as activation rather than training. The sequence I use is easy jogging, then dynamic mobility, then drills, then a few build-up strides, then into the work.
Progression. Start small and add slowly. A common entry point is 3-4 strides of 20 seconds with 60 to 90 seconds recovery, once or twice a week, building one stride at a time toward 6 to 8. For a team, the progression is the whole game. Decide in advance whether the next step is more reps or longer reps, and write it down.
Quick-Reference: Summer Stride Progression
A sample twelve-week build for a high school distance runner starting summer base in early June. Adjust the start point to the athlete’s experience: a returning veteran can begin at Week 3 or 4, a true beginner holds Week 1 for two weeks before advancing. The principle behind it is: change only one variable at a time, and decide the next step before you get there.
| Week | Sessions / wk | Reps | Length | Effort | Recovery | What changes this week |
|---|---|---|---|---|---|---|
| 1 | 2 | 4 | 15 sec | 85% | Full, walk back | Introduce the movement, focus on relaxed form |
| 2 | 2 | 5 | 15 sec | 85% | Full, walk back | Add one rep |
| 3 | 2 | 6 | 15 sec | 85% | Full, jog back | Add one rep, shift to jog-back recovery |
| 4 | 2 | 6 | 20 sec | 87% | Full, jog back | Lengthen the stride |
| 5 | 2-3 | 6 | 20 sec | 88% | Full, jog back | Add an optional third session |
| 6 | 2-3 | 7 | 20 sec | 88% | Full, jog back | Add one rep (down week: hold at Week 5) |
| 7 | 3 | 7 | 25 sec | 90% | Full, jog back | Lengthen the stride |
| 8 | 3 | 8 | 25 sec | 90% | Full, jog back | Add one rep |
| 9 | 3 | 8 | 25 sec | 92% | Full, jog/stand | Sharpen effort toward 800m rhythm |
| 10 | 3 | 8 | 30 sec | 92% | Full, jog/stand | Lengthen the stride (down week: hold at Week 9) |
| 11 | 3 | 6-8 | 30 sec | 93-95% | Full, jog/stand | Faster, at 800m to 400m rhythm; drop reps as effort climbs |
| 12 | 2-3 | 6 | 20-30 sec | 90-95% | Full, jog/stand | Season opens; shift to warmup-primer and pre-race use |
Reading the chart: every row changes exactly one thing from the row above. Surface stays flat and soft throughout (grass when possible). Effort percentages are submaximal by design, never all-out sprints. Build down weeks in roughly every third or fourth week by holding the prior week’s numbers rather than advancing, which is where the body absorbs the work.
Surface and terrain. Run strides on flat, even, soft ground when you can. Grass is ideal. The point is to be able to go fast safely, and to let the legs move through a full range without the pounding of pavement.
Note: Treadmills are a poor choice here. The belt does part of the work and changes the acceleration mechanics, which undercuts the whole reason you are doing them.
Pros and Cons of Strides in Summer Training
The case for strides
The base phase is mostly easy aerobic volume, which is correct. But mostly easy means almost no fast running for weeks, and that is when the top-end speed gets rusty. Strides are the cheapest insurance against that. They keep fast-twitch fibers and efficient mechanics present through a phase that would otherwise be entirely slow, and they cost almost nothing in recovery.
A thoughtful summer framework introduces intensity in a specific order, and strides come first, usually within the first two weeks. They are the lowest-risk way to introduce any speed at all, which makes them the right first step. For young runners who arrive in August having done nothing but slow jogging all summer, strides done consistently mean their legs already know 800m and even 400m rhythm when the season opens.
And the form work compounds. McMillan, in his high school coaching guide, groups strides with injury-proofing and running form work as the things that build durable runners with clean mechanics during the base. Better mechanics built in June pay off in October.
The cautions
Strides are low risk, not no risk, and summer carries its own hazards. A few honest cons.
- First, fast running on tired, unprepared legs is how soft tissue injuries happen. Strides are meant to reduce biomechanical risk over time, but only if introduced gradually and run on safe surfaces. Thrown at an athlete with no progression, on a hard or uneven road, they become a way to pull something.
- Second, the most common mistake in high school summer training is not strides, it is running the easy days too fast. Training too fast during the aerobic base period is described as the single most common summer mistake, the one that compromises the whole next phase. Strides can compound that mistake if they get run so hard and so close together that they turn into an unplanned workout. The discipline is keeping the easy run easy and the strides controlled and separate.
- Third, terrain matters more than coaches think, and unevenly so. Running frequently on hilly or irregular terrain is associated with higher injury risk for girls specifically. Running fast strides on a rutted trail or a cambered road is asking for trouble. Pick a flat, grassy surface deliberately.
- Fourth, the peaking fear. A handful of controlled strides twice a week does not produce a peak. It produces readiness. But the fear is real and worth naming so athletes do not quietly skip the work.
Net assessment: in a summer base, the pros clearly outweigh the cons, provided you progress gradually, protect the easy run, choose safe flat surfaces, and keep the reps controlled.
Putting It Together
So, Isabella, why do we add strides on easy days?
Because easy running lets the top of your range go to sleep, and strides wake it up for almost nothing. They keep fast-twitch fibers responsive, they sharpen the mechanics that improve running economy, they stretch stiff legs into a fuller range of motion, and they prime the nervous system for the hard work to come. They do all of it in about ten minutes, two or three times a week, at a recovery cost so low it does not interfere with anything else in the plan. That is why Daniels and Lydiard used them, and why the sharpest high school coaches assign them on right away at the beginning of the summer build.
Strides are the first and safest intensity you introduce. Run them on flat soft ground, build the progression a little at a time, and keep them controlled. Do that, and you arrive at the start of the season with an engine that has been quietly revving all summer, ready to go fast the moment you ask it.
The answer I should have given Isabella: Easy running builds the engine. Strides make sure you remember how to drive it.
Build the engine strides are meant to drive
Strides only pay off when they sit inside a base that is structured right: easy days kept easy, intensity introduced in the correct order, volume that builds without breaking your runners down. That is exactly what the 14-Week Norwegian Method XC plan is built to do. It lays out the full summer-to-season progression, where strides fit, and how the aerobic work underneath them is sequenced week by week.
