Fartlek Training Guide: Speed Play Explained

When I first heard the word “fartlek,” I laughed out loud.

I mean, come on — it sounds like something your stomach does after bad street food.

But once I tried it, I realized fartlek isn’t a joke — it’s one of the most powerful (and underrated) tools in a runner’s toolbox.

Fartlek — Swedish for “speed play” — is basically organized chaos.

No stopwatch.

No lap splits.

Just you, your surroundings, and some good old-fashioned bursts of speed. You might sprint to the next palm tree, then jog until you feel ready again. It’s effort-based, not pace-obsessed.

When I first started doing fartleks on the dirt trails near the temples here in Bali, I’d sprint to the top of a hill, recover by the rice paddies, then hammer it again toward a passing scooter.

It was messy and unstructured — but it lit a fire in my legs I hadn’t felt in a long time.

What Is a Fartlek Run?

The word “fartlek” literally means speed play in Swedish.

And that’s exactly what it is — you run fast, then run easy, all in one continuous session.

But instead of tracking exact reps and rest like you do in traditional intervals, you just… feel it out.

You might do 1 minute hard, 2 minutes easy. Then flip it.

Or you sprint to the next streetlight, then jog to the next stop sign. It’s about pushing and backing off — but on your terms, not a timer’s. You might the hills, jog the flats, and then let your body decide when to go again. It’s like playing a game with yourself. No pressure.

That’s the heart of fartlek. No fancy gear. No track. Just you and your instincts.

Why Fartlek Beats Boring Runs

Here’s why I swear by fartlek training — and why I have most of my athletes mix it in, especially when they’re feeling stuck or bored:

It Builds Both Speed and Endurance

When you crank up the pace during those surges, you tap into your anaerobic system (your fast-twitch muscles go to work).

Then when you ease off, you’re training your aerobic base — the slow, steady engine that keeps you going for miles.

Studies show this combo can actually raise your VO₂ max and aerobic threshold.

Translation? You can run faster for longer without dying.

I’ve seen this firsthand.

After just a few weeks of fartlek sessions, some of my newer runners say their long runs feel easier — and their short efforts start to pop.

Your turn: What’s your usual pace on a long run? Try sprinkling in some 30-second surges and see what happens in a few weeks.

It Builds Mental Grit

There’s no schedule to hide behind in a fartlek.

You don’t know when the next sprint is coming — and that’s the magic.

Fartleks teach you to push through random discomfort, just like in a race when someone surges or you hit an unexpected hill. Changing up between effort and recovery builds mental resilience by teaching you to adapt to changing paces. This isn’t just about your legs — it’s about your mindset.

Fartlek trains your brain to stay calm when things go off-script.

It Mimics Real Races

You ever had to chase someone down during a race?

Or recover fast after flying up a hill?

Fartleks prep you for exactly that. You train for the unpredictable — and that pays off on race day.

I’ve had runners tell me that after a few weeks of fartleks, they felt more in control during events, even when the pace surged.

It’s Made for Trails and Hills

On Bali’s volcano trails, you can forget about “maintaining pace.” The terrain shifts too fast for that.

That’s why fartleks are gold on trails.

One Kenyan coach once said that fartlek is perfect for uneven terrain because it flows with the land — go hard on a climb, recover on the downhill.

It’s like playing tag with the earth. And it builds the kind of leg strength and adaptability no treadmill can give you.

Burns More Calories Than Steady Runs

Because fartleks are a form of high-intensity interval training (HIIT), they spike your heart rate. That makes your body work harder — and burn more fuel.

Some research suggests fartlek workouts can torch up to 30% more calories than steady-state jogging. Not bad for a workout that doesn’t require a stopwatch.

So if your goals include getting faster and shedding a bit of weight, fartleks hit both.

Fartleks vs. Intervals: Same Family, Different Attitude

Let’s get one thing clear—fartleks and intervals aren’t twins.

They’re more like cousins who train differently.

Intervals are rigid: “Do 6 x 400m at 5K pace with 2 minutes rest.” It’s structured, predictable, and great for building pace.

But fartleks?

They’re wild. Unscripted. You never fully stop, and you don’t need a stopwatch to get the job done.

With fartleks, you’re making the calls as you go.

If you feel strong, you surge. If you’re gassed, you dial it back. I’ve done fartleks where I sprinted every hilltop on a trail, and others where I hit every third bend on a track.

Beginner Fartlek Tips (Real-Runner Style)

Before you head out the door for a fartlek run, make sure of the following:

Start with a base:

If you’re just getting into running, don’t jump straight into fartleks.

Build some rhythm first.

Run 3 to 4 times a week for a couple of months. That’s how you get your legs, lungs, and joints ready to play with speed.

No shortcuts here.

Your body needs time to handle the extra load. Trust me — your knees will thank you for not rushing it.

Keep it simple:

Your first fartlek doesn’t need to be fancy.

Just try 20 to 30 minutes total, after a solid 10-minute warm-up. Go for something like 4 rounds of 30 seconds fast, 90 seconds easy.

That was my first one, and yeah — it humbled me. I felt like I was flying and dying at the same time. But it taught me how to find that edge without overcooking it.

Adjust as you go:

One of the best things about fartleks? You’re in charge.

If a surge feels too easy or way too hard, tweak it.

Some days you’ll crush it. Others, you’ll feel like you’re dragging bricks.

That’s normal. Roll with it. The goal is effort, not perfection.

Don’t fear the hills:

Got a hilly loop nearby? Use it.

Surge up that short, nasty incline, then jog the downhill as your recovery.

It’s like sneaking in strength work while you build speed. No gym required.

Cool down or pay the price:

Always end your session with 5–10 minutes of super easy jogging or walking.

That’s when your body starts to clean up the mess you just made — flushing out lactate, lowering your heart rate, and prepping you for the next run.

Don’t skip it. You’re not done until you cool down.

How Often Should You Do Fartlek Training?

If you’re just starting, once a week is plenty.

Replace a midweek tempo run with a fartlek session.

Don’t rush into speed work unless you’ve already built a solid base—3–4 months of steady running first.

Once your body adapts, bump it up to two sessions a week max.

Always listen to your body. If you’re feeling beat up—scale back. Fartleks are sneaky tough. The sudden pace shifts hit your legs hard if you’re not warmed up right.

Coach’s tip: I like placing fartleks midweek, surrounded by easy days. Keeps things fresh, and it turns that session into something I actually look forward to. Like a game—not a grind.

Real-World Inspiration: Kenya Knows the Game

Ever see how runners train in Kenya?

They do fartleks in packs, out on trails and dirt roads — just playing with speed.

No stopwatch, no pacing charts. Just someone yelling “go!” and the whole group surges until someone calls it off. Then they jog, laugh, recover, and hit it again.

It’s simple.

It’s raw.

And it builds more than speed — it builds mental toughness.

I’ve done the same here in Bali with my training group. We call it “landmark racing.” One of us shouts, “Next tree!” and we all take off like kids. It’s chaotic, and it works. You learn to suffer together — and that kind of grit stays with you on race day.

Fartlek Workouts You Can Steal and Make Your Own

Fartleks don’t need fancy charts or zones.

Just effort and play.

Here are a few templates I’ve used and shared with athletes I coach. Steal them, tweak them, make them yours.

Always warm up with 5–10 minutes easy jog and cool down afterward.

1–2 Minute Surge Mix

• Alternate 1 minute hard, 2 minutes easy, then flip it: 2 minutes hard, 1 minute easy.
• Run 3–4 cycles. It’s a great 40–45-minute intro. Verywell Fit actually recommends it for beginners—and I second that.

Pyramid Fartlek

• Great for simulating race effort.
• Go 2 minutes hard / 2 easy → 3/2 → 4/2 → then back down.
• Recover with jogging between efforts. Think of it as your “rolling hills” workout—even if you’re on flat ground.

Landmark Fartlek

• This one’s pure old-school. Spot a tree, gate, or pole—sprint to it.
• Then jog. Then find the next one. A Reddit runner said, “I find a tree and sprint to it, then recover.” No fancy GPS needed. It’s simple and it works.

Kenyan-Style Fartlek

• Inspired by how elites Kenyans train.
• Run 4–6 miles, and each mile should be just a bit quicker than the last.
• Start smooth, build pressure, and end with everything you’ve got left. It teaches you how to finish strong, even with tired legs.

Race-Specific Fartlek (5K/10K)

• Want to sharpen for a race? Do 8–10 bursts of 1–1.5 minutes at 85–90% effort.
• Between each, jog easy for a minute. You’re touching race pace over and over without the burnout. Boosts speed, builds VO₂ max, and gives you mental reps too.

Treadmill Fartlek

• Stuck indoors? No excuses. Hop on the treadmill and try this: Alternate 1–2 minutes at a strong pace with 1–2 minutes easy jog or walk.
• Add 1–2% incline to spice it up. One trainer even sprints during TV commercials or song choruses—it turns the workout into a game. Sunny Health Fitness loves this approach.

Fartlek Fast Facts & FAQs

Why do fartleks work so well?

Studies show they can make running hard feel about 10–20% easier over time.

Your heart gets stronger, your brain gets more comfortable with the effort, and your form starts to sharpen up. It’s speed training with less mental load.

What exactly is a fartlek?

It’s Swedish for “speed play” — and that’s exactly what it is.

You mix faster running with slower jogging or walking in one continuous run.

No rigid timing. You go hard when you feel like it, then back off to recover.

How often should I do them?

Once a week is plenty if you’re new to it — or once every two weeks to start.

Give your body time to adjust. These sessions hit hard if you’re not used to them.

Can I do fartleks on a treadmill?

Absolutely.

Try 20 minutes alternating 1–2 minutes fast with equal time easy.

You can even sync it with music or commercials. I’ve coached runners who prefer treadmill fartleks — the incline control is great for mimicking hills, and you don’t have to guess your pace.

Your Turn: Try a Fartlek This Week

Ready to test yourself?

Don’t overthink it.

Jog 5 minutes, then do 5 rounds of 30 seconds hard, 90 seconds easy. Cool down at the end. Boom — first fartlek in the books.

You might giggle at the name — but trust me, it’s no joke.

This kind of running builds real power, inside and out. I’ve seen beginners smash plateaus and veterans fall in love with running again, all because they added fartleks.

So —

What’s your favorite way to mix up your runs?

Tried a fartlek before? Drop your story — let’s compare war wounds.