Fartlek Workouts for the 5K to Marathon

Fartlek Workouts for the 5K through Marathon

In addition to tempo runs, one of my favorite running workouts for myself and my athletes are fartlek workouts. Not mile repeats, not quarters, not even hill repeats: just fun and effective fartleks. 

I could (and will, soon) devote an entire post on different methods of building speed without increasing your risk of injury. One tried and true method: fartlek workouts instead of traditional speed workouts on the track.

What’s a fartlek workout? It’s a Swedish word for “speed play.” In a fartlek run, instead of pushing yourself hard at a particular pace for a designated distance (3 x 1 mile at 5K pace, for example), you focus on a hard but not all out effort for a certain amount of time.

You can even create an even more unstructured fartlek by running faster for a few blocks, easy for a few blocks, and repeating, or by running faster every time that an angry goose begins to chase you on the trail (or does that just happen to me?).

One common cause of running-related injury is doing too much too soon. Speed work done all year round, or even in the early weeks of race training, can cause you to push yourself too hard too soon, especially if you are basing your paces off of older PRs or goal times rather than your current fitness.

Fartleks provide the integral step between the easy runs of the base building phase and the mile repeats of the sharpening phase. The fartlek run prevents you from doing too much too soon since they usually cover less distance at a lower intensity than traditional speed workouts. You run a fartlek by effort, not by a prescribed pace, which means you are running according to your current level of fitness and are not pushing yourself too hard too early in training.

Even if you’re not injury-prone, fartlek workouts are an ideal form of speed work for most stages of training. They’ll keep a bit of speed in your legs during the off-season and base building, they’ll transition you from base building to race training, and they’ll release you from the stress of hitting specific paces during race training.

Most of all? Fartlek workouts are fun! Very runners actually make money from the sport; most of us do it for fun, so why not keep an element of fun in your running, even when you’re training hard for a goal race?

Fartlek Workouts for the 5K to Marathon

Fartlek Workouts for the 5K to Marathon

5K Fartlek

The purpose of 5K training is to get comfortable with being very uncomfortable for a short amount of time, so your workouts should serve that purpose. A quick cadence and fast foot turnover is vital for running a strong 5K, so fartleks that emphasize quick bursts of very hard running will help you become a more efficient runner and prepare your body for the demands of 5K race specific speed work.

This workout is actually an all-around versatile workout which any runner can utilize, whether they are training for a 5K or a marathon. It’s an ideal workout for the early weeks of training, when you’re focused on transitioning from base building to speed work.

The Workout: Warm up with 1-2 miles at an easy pace. Repeat 12-15 repetitions of running hard (at 5K race effort or slightly faster) for 1 minute and running easy for 1 minute. Cool down with 1-2 miles of easy running. Focus on taking short and quick steps during the hard running segments.

10K Fartlek

10K runners want to achieve a good balance between endurance and speed. To run a successful 10K, you need to learn how to how a fairly hard pace for a decent amount of time, which means that a smart sense of pacing is necessary to keep you from starting out too fast and slowing down over the last 2 miles.

For 10K runners, fartlek workouts are ideal for the earlier weeks of training; when you approach the final weeks before the race, you want to practice running at your goal pace with measured distance workouts as as 800 meter or mile repeats.

The Workout: After a 2-3 mile warm up, run for 4 minutes at a hard effort, 2 minutes easy, 3 minutes hard, 2 minutes easy, 2 minutes hard, 1 minute easy, and 1 minute hard. Run easy for 5 minutes and then repeat the fartlek again before cooling down for 1-2 miles. Your hard effort should be in the range of 10K to 5K race effort; what matter is being able to sustain an even effort for all of the hard intervals without slowing down.

10 Miler/Half Marathon Fartlek 

So, tell me if this has ever happened to you: you’re gliding along at a comfortably hard pace for the first 8-10 miles of your half marathon, when suddenly you feel as if you can’t move your legs any faster. No matter how hard you push (and you feel as if you’re pushing at your very limit), you see the clock along the course or check your Garmin to realize that you are actually slowing down.

It’s happened to me! My solution to this conundrum came from Brad Hudson’s Run Faster from the 5K to Marathon, which if you’ve been following my training for the Lake Sammamish Half Marathon, you know that I’ve been following an adapted version of Hudson’s plan. One of the workouts Hudson’s half marathon plans call for are fartlek long runs, which served as an inspiration for this workout.

This half marathon fartlek workout serves to teach your legs to pick up the pace after you’ve been running for several miles. After adding a few fartlek long runs into your half marathon training, you won’t struggle to speed up during those last few miles of the race. Instead, you’ll be passing other runners and finishing your race strong.

The Workout: Run 8 miles at your normal easy long run pace. Once you reach mile 8, alternate between 2 minutes at tempo effort (half marathon effort or just slightly faster) and 2 minutes at an easy effort for 3-4 miles. Tempo effort should feel comfortably hard with a breathing pattern of 2 counts inhale, 2 counts exhale.  This workout will cover 11-12 miles and can take the place of an easy long run.

This workout is also effective if you’re training for a 10 mile race!

Marathon Fartlek

Too much speed work during marathon training will cause injury before you can actually reap the benefits of regular speed work. Since the priority of marathon training should be on long runs, goal pace runs, and safely increasing your weekly running mileage to improve your aerobic fitness, fartleks are an ideal speed workout for marathoners.

By running according to effort, you avoid pushing yourself harder than you should just to hit an arbitrary split time. Fartlek workouts also usually cover less distance at a lower intensity than traditional speed work, so they’re ideal for marathoners who are already pushing their bodies to the limit with long runs and high mileage.

Long fartleks are an excellent workout for full marathoners, but don’t neglect the value of short bursts of harder when you’re training for endurance events. You don’t need to push yourself to a vomit-inducing pace; fartlek intervals between half marathon and 10K effort (moderately hard) will provide you with all of the benefits of speed work without the risk of injury.

The Workout:  Try this fartlek workout sprinkled throughout the earlier and middle weeks of your marathon training cycle. Warm up for 2-3 miles, run 6-8 repeats of 3 minutes at a moderately hard effort (10K effort) and 2 minutes easy, then cool down for 2-3 miles.

For many runners, you will cover just under half a mile in these workouts, but they’re easier on the mind and the body than all-out 600 meter or 800 meter repeats. Meanwhile, you’ll cover anywhere from 8-11 miles in this workout, depending on your speed and number of repeats, which means this workout will also help you increase your endurance.

Fartlek Workouts for the 5K to Marathon

Where to Run Fartleks?

Personally, I love to run fartleks on the road or a multi-use paved path (no spotlights means no stopping!). You could run these on the track, but the repetitive motion of the track increases your risk of injury such as IT band syndrome. Running on the roads or smooth trails also means you will not be running on a completely flat surface, which is beneficial as well to teach you how to pace as elevation rises and drops. Fartleks are also a great way to prevent treadmill boredom if you’re stuck inside due to weather!

When Should You Hit the Track?

Unless you are training for a track race, you should really only hit the track for specific interval speed work such as 400s, 800s, and mile repeats during the sharpening phase of your training. The sharpening phase occurs in final few weeks of training before you taper for a race, when you already possess a strong sense of an appropriate goal race time and are doing those last few workouts to prime you for the race.

Disclaimer: I am a certified running coach, but I may not be your running coach (want to work with me? Learn more about my coaching services here!). Always consult your coach if you have one and train in a way that is best for you, your goals, and your body. 

Linking up for Wild Workout Wednesday

Enjoy this post? You may also like:
Turning Track Workouts into Fartlek Runs
Early Season Running Workouts to Safely Build Speed
Fartlek Countdown Workout for Off-Season Speed Work

How do you keep your training fun?
Do you include fartlek workouts in your running routine?


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22 Responses

    1. Thank you – I’m glad you like them! Fartleks are so great for easing into speed, especially after a while off from training or when it’s extra hot or cold outside!

  1. Great post! (as always). We actually tried out something new with the trainees at coaching the other week: negoitiated fartleks. They got to decide the intervals for themselves, (we gave them a range) and they could decide on the run, but they couldn’t all choose 30 seconds or whatever. It actually was a great and fun way to do it!

  2. This is a great post and I think workouts like this work for all runners. It can be hard to get to the track especially alone and when at the track, people tend to all try to run together and beat each other and sometimes that results in running the workout faster than you really should. I like doing minutes “hard” then “easy” especially on the treadmill in the winter months.

    1. Thank you! Track workouts really can turn into competitions, and then some runners lose the benefit of training in the right zone. And fartleks are great for beating treadmill boredom and adding a bit of faster running to winter training!

  3. I do fartleks on the treadmill to make the time go by faster. I’ll either use time or music! So I’ll run hard for 2-3 minutes and then recover or I’ll run hard for a song and then recover for the next one.

    1. Music fartleks are a fun variation also! Plus I bet the factor of uncertainty (not knowing exactly how long a song and the segment of faster running is) makes them great for building mental endurance also.

    1. Thank you! I hope you enjoy the workout – let me know how it goes! I did it last week for my half marathon training and it’s not as bad as it sounds – and is actually quite fun!

    1. Thank you! I hope you enjoy the half marathon fartlek workout if you try it! It’s a good one for getting faster without getting burnt out – hard, but adjustable to effort so never too hard.

    1. Thank you for pinning! I haven’t been injured in over 6 years, and I think a lot of it comes from doing more fartleks than speed work. Effort based is so good for getting faster but not pushing past the point of benefits and into the land of injury and overtraining!

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