Inside John Korir’s Training for the 2026 Boston Marathon

John Korir has had one hell of a year. He won the 2024 Chicago Marathon, and then he turned around and won the 2025 Boston Marathon.

For someone who previously won LA in 2:09-2:12, ran Boston in 2:10, and ran Chicago in 2:05, it’s a big come up. From 2021-23, he was good. But in 2024 and 2025, he was great. His 2:02:44 win at Chicago puts him #8 on the all time men’s list.

Lately, I’ve been exploring some elite athletes’ Strava profiles to see how they train. Most of these runners are American or Canadian. So I was surprised to find out that John Korir has a public Strava profile – and anyone can browse through his training. It’s not often that you can get direct visibility into one of the world’s best marathon runners.

A couple weeks ago, I did a deep dive on Conner Mantz’s training for the Boston Marathon. Today, I’m going to do a similar review of John Korir’s training.

A few questions that we’ll answer along the way:

1. How many miles per week does he train?
2. What does a typical weekly schedule look like?
3. What kind of long runs does he do?
4. What is his “easy” pace?
5. What are some typical workouts?
6. What does his taper look like?

So let’s dive in.

How Many Miles per Week Does John Korir Run?

It’s typical for professional marathon runners to put in 100+ miles per week. When I looked at the mileage of some of the top runners in the United States, they were all doing ~120-130, and Conner did about 120 in his build up for Boston.

Where does John Korir fit in?

Korir often takes periods completely off, and in late December he was just getting back into training. So the week ending 12/22 has very little mileage.

The next three weeks, he put in just about 100 miles per week. Then, he got into serious training – hitting 140+ four times throughout the next couple of months.

If you follow the line in the graph, you can see it bounces up and down a little bit. Two peaks weeks, a “lower” week, another high week, another lower week, and then two more peak weeks.

For him, those low weeks are under 120 miles – which would be tough for the rest of us. But I guess when you’re putting in 140+, that is a relative down week.

There is one week with drastically reduced mileage – the week ending 3/23. He only logged a couple of activities that week and then took the rest of the week off after Tuesday. There’s nothing on his Strava or Instagram to indicate why, so it’s unclear if he was nursing an injury or just took some downtime.

Notably, this is considerably more mileage than he put in on the way to Chicago. Last fall, his highest week was 132 miles – with most of his heavy weeks in the 120’s. It’s also more than Conner Mantz did.

What Does a Typical Weekly Schedule Look Like?

Most weeks, John Korir ran six days – three easy days, two workouts, a long run, and a day off on Sunday.

During the lighter weeks, his easy days would involve a shorter run (~10k) and a longer run (~21k). But in his heavier weeks, he added in triples. Monday and Wednesday typically included a slower 10k in the early morning and the evening, and a longer run of 20-25k in the middle.

Tuesdays and Thursdays were typical workout days Usually a workout in the morning and an easier run later in the day – but sometimes flipped around.

Then Saturday typically featured a long run of 21-25 miles at a good clip.

Here’s an example of one of his heavy weeks, the week ending 2/9/2025:

• Monday: Easy morning 10k (7:52/mi), Moderate afternoon 21k (6:43/mi), easy evening 10k (8:11/mi)
• Tuesday: MP tempo (11.2 miles + 2WU + 2CD), easy 10k double (7:41/mi)
• Wednesday: Easy morning 10k (8:05/mi), moderate afternoon 20k (6:57/mi), easy evening 10k (8:16/mi)
• Thursday: Easy morning 10k (8:59/mi), Fartlek workout, faster than MP, 12 miles + 2WU + 2CD
• Friday: Easy morning 10k (8:30/mi), Moderate 20k (6:55/mi)
• Saturday: 24 mile long run (5:35/mi)

That’s pretty typical of his schedule, with the lighter weeks less likely to feature triple runs on Monday and Wednesday.

The fartlek workout on Thursday was a run with 1.5k to 2.5k segments at somewhere between threshold and marathon pace. It was out on the road – not on a track – and the interval lengths varied. It’s unclear whether there was specific structure to the intervals or not.

What Kind of Long Runs Does Korir Do?

Every Saturday, John Korir went for a long run. There were only three weeks that varied this schedule.

In one week, he ran his long run on Thursday, and in another case he took off Wednesday through Sunday and didn’t do a long run. The third time, he had a regular week but skipped the Saturday long run.

For the most part, these long runs varied in length from 21 to 25 miles. He did do one 19 mile long run in the middle of training, and then his long runs in the start of his taper were a bit shorter.

His pace on these runs typically averaged around 5:30/mi, give or take.

Often, these runs started out slower – 6:00-7:00/mi for the first couple miles. Then, he’d progress to a faster pace towards the end. He’d often finish around 5:00/mi or in the high 4:00’s – around or slightly slower than marathon pace.

He didn’t do any long marathon pace tempos during his long runs – although he did do some longer marathon tempos during his workouts.

It’s also interesting to note that his long runs were typically quite hilly – with anywhere from 1,500 to 2,000 feet of total elevation gain. That’s twice the total elevation gain at Boston, and they often ended with an incline as he was progressing towards his faster pace.

What’s His Pace On An Easy Day?

This was a really interesting part of his training log. Korir’s easy paces vary over quite a large range.

On his regular easy runs – the midday 20-25k runs – he’d typically average between 6:30 and 7:00/mi. These runs also often had 1,000 or more feet of elevation gain.

But on his shorter runs – the doubles and the triples – he was very slow. A couple of these runs averaged in the 7:00’s, but most of them were in the 8:00’s, and a handful averaged 9:00/mi or more.

There’s something of an urban myth on the Internet that some Kenyan runners run super slow at times. It’s often called the Kenyan shuffle.

In some cases, this is described as the beginning of the run. You start super slow, and before you know it, you’re gliding. This is what Michael Crawley describes in Out of Thin Air.

But other times, this is confused as running slow for an entire recovery run. From a Facebook post: “The Kenyan shuffle is essentially a very slow recovery run. A majority of elite Kenyans do their miles at a comically slow pace, around 6:00 – 7:00 min/km.”

And then that’s touted as evidence that you should go as slow as humanly possible.

Korir’s training sheds some really useful and interesting light on this.

On the one hand, he does do some runs that are “comically slow” for an elite runner like him. On one recovery jog, he covered 10k at a pace of 8:54/mi – and his heart rate was mostly in the 110’s and 120’s. And yes, the pace was even slower for the first mile as he eased in to things.

On the other hand, these are exclusively doubles, triples, and warm ups. On days that he did a workout, his warm ups and cool downs were often 8:00 to 9:00/mi or slower.

But there was rarely a day that he didn’t run at an average pace of at least 7:00/mi during his main run. And even if his average pace was above 7:00/mi, the core miles were in the 6:00’s.

For example, on January 13, he ran 13.05 miles in the late morning. He’d already done an easy 6.5 miles at an average pace of 7:30/mi earlier in the morning. His first four miles were 8:12, 7:15, 7:27, and 7:20. The remainder of his run was between 6:39 and 6:54 per mile.

So, yes. There’s evidence here that Korir (and by extension, the other Kenyan runners who trains with) takes some of his recovery runs at very slow paces. But those super easy paces are reserved for warm ups, cool downs, and added mileage.

His core runs – including his core easy runs – are at a much faster (but still relatively slow) pace.

What Are Some Typical Workouts?

Korir doesn’t offer a lot (usually none) of commentary on his runs. And some of his workouts don’t have complete split data available on Strava – either because of the way he uploaded it or because of the way the website is set up.

So it’s sometimes difficult to figure out exactly what the workout is.

But one common workout is a marathon pace tempo. For example, on February 13, after a 2 mile warm up, he did 12.44 miles at 4:44/mi. The pace varied a bit, and he covered 715ft of elevation gain. But on average, that’s around his marathon pace.

Another common workout is a fartlek of sorts. He’d alternate periods of harder running (marathon to threshold pace) with short (~30s to 60s) recoveries. For example, on March 6 he ran 12.42 miles at an average pace of 5:16/mi. That one included some 2k repeats and some 1k repeats, along with 1 minute rests. His working pace was around 4:50/mi early on and closer to 4:30/mi towards the end.

I’m guessing that the runs that are uploaded with times and distances, but no laps, are his track workouts. The rest of his runs are on the road, and from his Instagram you can tell that he does some track workouts. So it’s hard to say what types of workouts these are – but my guess is threshold repeats of some kind.

He pretty consistently logged a 2 mile warm up and a 2 mile cool down – as separate activities – on days that he logged a workout.

I initially had trouble finding the details of his Tuesday workouts. But I figured out how to view them on the Strava mobile app, and you can find the details here.

What Is His Taper Like?

Korir tapered hard.

He did his last really big week – 145 miles the week of March 2 – long before Boston. After that, his weeks were in the 110-120mpw range.

Three weeks out, he did 105 miles. He still did Tuesday and Thursday workouts, but they were shorter and he didn’t do doubles that day. His triples on Monday and Wednesday were gone. His easy days were also getting slower. And his long run was only 19 miles that week.

Two weeks out, he dropped to 78 miles. The Tuesday/Thursday workouts were even shorter. The regular mid-day runs were shorter, too. For example, Mon he did 7.2 miles followed by 7.2 miles – instead of the usual 7.2 followed by 13-14 miles. And his long run was 16 miles that week.

The week before Boston, he only did 38 miles. He ran once a day, no doubles. I saw somebody on Threads point out that he ran nothing faster than 8:00/mi that week, and that’s part of what made me want to take a closer look.

That’s partially true. Most of his runs did average above 8:00/mi. But on Wednesday, he ran five miles – 8:46, 8:00, 7:39, 7:49, 7:59. And he did bang out one workout.

On April 15 (Tuesday), he did 10x1k repeats at a pace of 4:20-4:30/mi – roughly threshold pace. The workout details are available in the Strava mobile app, but not on the website. His track workouts all seem to be like this – it must be a quirk of the differences between Strava on the web and Strava on Android.

Regardless, his last week was super easy – but it did have some intensity thrown in. For a runner of his caliber, staying above 8:00/mi for almost an entire week is pretty impressive.

What Can We Learn From Korir’s Training?

As I pointed out when we took a look at Conner Mantz’s training, we’re not elites. So we should be careful when drawing conclusions and applying them to our own training. But I think there are a few useful things we can learn from how John Korir trained for Boston:

• Elevation is your friend, especially if you’re training for a hilly race. I can’t help but notice that Korir did way more elevation than Mantz. His long runs typically had more gain than Boston, and his weeks averaged 8,000 to 10,000 feet of elevation gain. Mantz was typically around 2,000 to 3,000, with a few weeks at 4,000+. And Korir won the race by charging ahead when they got to Heartbreak Hill – where most people slow down.
• Take the doubles easy. I mentioned this in the post about Mantz, and I’ll double down here to say that you can go really easy on those extra miles. If Korir finds value in a 8:45/mi 10k – then there’s no need for you to be pushing the pace on a double.
• Similarly, it’s ok to start out super slow and speed up. The Kenyan shuffle is a thing – in that the first mile or two of Korir’s runs are often very slow. If your legs aren’t cooperating, slowly work them up to speed – instead of trying to hammer the rust off.
• But that doesn’t mean you should go slow all the time. Other than his off day, there’s never a day that goes by that Korir doesn’t run sub-7:00/mi. To him, that’s still relatively easy, and it’s definitely aerobic. But it’s not shuffling super slow, slow.
• Push the pace on long runs. This is a commonality between both Korir and Mantz. Their doubles are slower than their easy days, and their easy days are slower than their long runs. Outside of a few warm up miles, they’re pushing the long runs to the top end of their aerobic range. It’s very Pfitz-like.
• Threshold and marathon pace tempos are the way to go. He did some track work that was a little faster. But most of his workouts were fartleks between threshold and marathon pace, or they were marathon pace tempos.
• Triples are a thing. I’m not at that level, but if you’re already doing 2 runs a day, five days a week, try adding a super slow triple a couple times a week. Korir did them 2-3 times per week, and that made the difference between 120 mpw and 140 mpw.
• One more vote for Team Six Days a Week. I’m still in the seven days a week camp, because i like the consistency. But Korir is clearly evidence that you can train at the highest levels and still take a day off if that’s how you roll.

For some more details about his individual workouts, check out this follow up post.