Running Intervals – Speed And Fun All Year Round

Running is an easy sport.

Lace up your shoes.

Walk out the door.



But how can you get the most from your running? How can you continue to improve – more just can’t always be the way.

Unless you are a track sprinter, most run races/events/adventures are going to be around 95 to 99% aerobic – which means that you’re using oxygen to help fuel, and as a result the majority of your running should also be aerobic. This means comfortable effort, predominantly maintaining the ability to hold a conversation. If you can hold a conversation, it means that enough air is getting not only to your lungs, but then into the bloodstream to help with converting fat and glycogen (sugars) into energy.

The problem is, if we want to get faster, and want to avoid being a one paced athlete, we need to change things up at least a little bit.

This is where running intervals comes in. Interval training in it’s simplest form means that you aren’t doing everything at the same pace. Running intervals trains your body and mind to be able to change gear – whatever your speed or ability – and trains your body’s systems to shift through the gears too.

Because running is a super high impact sport – 4-5 times your body weight goes through your lower limbs every time your foot hits the ground – we can’t do too much running at a higher intensity. But dialling things in so that you do enough to make a difference isn’t too difficult.

The best part is that you can do some form of interval training all year round. The duration of the intervals might change. The amount of recovery might change. The level of intensity may be what you vary. Even how you divide up your run might alter. Whatever it is that you decide to affect, there are plenty of different options to help mix up your training, keep you interested and motivated, and help keep you improving.

Interval training involves running hard for short periods followed by longer recovery periods where you jog or even walk. Not to labour the point, but the effort periods really need to be tough for running interval training to deliver its benefits, which include improving your running efficiency and your ability to maintain higher speeds for longer. As a rule, if you get halfway through your recovery period and feel able to run hard again, the chances are you didn’t push yourself enough on the previous interval.

Fartlek Training

The simplest form of intervals that you can do is fartlek running intervals. Fartlek, roughly translated from its original Swedish, means “speed play.” Fartlek training can be done quite literally anywhere and can be as structured as you like. So if you enjoy running on the trails and in the middle of nowhere, you don’t need anything fancy to track it.

As a result, fartlek training is great for running in the winter, and it’s perfect for newer/less experienced runners – because it teaches you that running isn’t just about the pace on your watch that you are trying to maintain. It’s all about managing your effort and output – and learning what that feels like.

1) Free-form fartlek

These sets take the words “speed play” to heart – the workout is truly governed by how you feel. After a good warm-up, you can pick up the pace and intensity whenever you feel like it.

Free-form workouts are best done with a group of runners who share the same level of fitness and ability – you will keep each other honest by making sure there isn’t too much time in between hard efforts and ensuring those hard efforts are hard enough. You could vary between efforts, jumping up or down as you see fit, or you could keep stepping the pace up (something that can often happen in groups!).

2) Timed Fartlek

There’s no limit when it comes to setting up these workouts, especially now that so many watches allow you to set a variety of timers. The timed workouts should be organized based on your goals and training needs at various stages of your training program or the year. You could do efforts from 10 seconds in length up to a few minutes – the choices are endless.

If you’re building your levels of fitness at the front end of the year, you’ll want to emphasize your strength and aerobic fitness with intervals of between three and five minutes and give yourself about half the time of the interval as a recovery.

Later on in the year, if you have some races planned, you’ll need to emphasize threshold training, helping you to develop the ability to hold your heart rate at a higher level for longer periods of time. If you’re choosing to develop speed, you should do some shorter intervals with longer recovery times.

Finally, as you get close to your “A” race of the year, you’ll want to test your fitness with some longer intervals with short recoveries done at your goal race pace.

3) Distance Fartlek

This might be something that depends on where you are running (road/trails/sports pitches), but you can decide in advance how you are going to structure you changes in effort/speed. If you’re running on the road, choose lamp posts, road signs or road markings to effect a change on your intensity. If you’re on sports pitches, you may choose to accelerate/decelerate at the corners. If you are on trails, pick trees or markers along your way and kick on, or ease back!

Fartlek training to do running intervals really is as easy as that (although they can be quite hard!).

Beyond fartlek, running interval training can be a bit more specific, either in distance or in time.

Classic Running Intervals

One of the attractions of classical interval training is its measured, precise nature. Workouts can be tailored to a runner’s current ability level; similarly, they provide an accurate benchmark of one’s fitness, allowing achievable competitive goals to be set. Interval training’s repeatability provides comparisons to performances of a month or five years ago.

Conversely, it also possesses an almost infinite variety. By altering different segments of the workout, it’s possible to come up with a new training session each time you run out the door.

To be as specific as possible, it’s a nice where possible to run these sorts of sessions on a flat and open path. If you had the opportunity, running on a track is even better – you know exactly where you stand, and chances are you won’t have to battle a slope – but not everyone has that option all the time.

Interval training was first developed by German physiologists Reindell and Gerschler in the 1930s, based on their findings that the cardiovascular system responded to repeated brief bouts of stress by becoming stronger and more efficient. By keeping the duration of these efforts relatively short, they found that runners could complete a greater volume and intensity than they could during a sustained, continuous effort.

There are four variables in classic interval training, easily remembered by the mnemonic D-I-R-T.

D for Distance is rather self explanatory, referring to the length of each repetition.

I stands for Interval, which in Reindell and Gerschler’s system is the recovery period between repetitions. It is during this interval, especially the first 10 to 15 seconds, that most of the training effect occurs. Besides the duration of the interval, the activity (usually walking or jogging) figures into the equation. One of the original principles of interval training that is still accepted in some circles is that the next repeat should not begin until the athlete’s pulse has dropped to 120 beats per minute.

R is for Repetitions, the number of fast sessions to be performed. In longer workouts, repetitions can be broken down into sets, with a longer recovery interval than between individual reps.

Finally, the T stands for Time, how fast each repetition should be run. This can be constant or variable, depending on the goal of the workout.

All four of these variables are interrelated, and like a mathematical equation, changing one either affects the others or the final outcome. Knowing how this interaction functions will allow you to better understand interval training, and how to modify your workouts to your best advantage.

If you look at an example session, it may take this form: 8 x 400 holding 90 – 2 mins ri. That’s track language for eight efforts of 400 meters run in 90 seconds, with a two minute recovery. To increase the difficulty of this workout, there are four changes we could make to the formula (and like any school science experiement, it’s sensible to only alter ONE of them at a time).

The number of repeats could be raised to 10, 12 or more, the distance could be increased to 600 or 800 meters, the pace could be increased to 85 or 80 seconds, or the recovery time could be reduced to 1:45 or 1:30. Obviously, if the original session was too tough, changing any of the variables the opposite way would make it easier to complete.

Which change you make depends on your goal for that training session. To learn to run at a particular pace (e.g. six minute miles) in a race, keep the pace the same and reduce the distance and/or increase the number of reps. On the other hand, if you are working on being able to run farther at a strong pace, lengthening the reps may be a better option.

This leads to what I feel are the two most important rules of effective interval training:

1. Go to each workout with a goal, and a plan. Don’t just say “I need to get fast, I’m going to smash myself to bits.” Different workouts have different training effects; 20 x 200 and 4 x 1,000 have little in common besides the total distance being the same. With this knowledge, and the understanding of the basic principles of interval training, you can sensibly follow the next rule:

2. Be flexible in your workouts, but within reason. Many runners throw speed into their weeks and plans haphazardly. They figure speedwork is speedwork, and it doesn’t matter what they do, it’s got to make them faster. Perhaps, but doing the workout of someone pointing for a 5K next month may not help you very much in your marathon in the fall. Beware of falling prey to a mindless group mentality. Refer back to Rule 1, and see if you can adapt or modify the workout to fit your training goals (chances are, most workouts can!).

With all of this, you can pick a speed session of some sort for any time of the year. When you are building fitness, or having fun after races have finished, being specific isn’t important. Doing some form of running intervals breaks up the week, keeps you motivated and feeling like you have done something fun. When the work really begins, you can start with some short sharp intervals to get the legs moving; maybe move to something a bit longer as you get fitter and stronger to improve your general pace and overall speed; and then work back down to the short stuff to get really fast!

Just be careful with how much speed running you do in a week. Running harder and faster puts more stress through the body. So as mentioned up at the top, no need to overload it more than is necessary. Make sure that you do your recoveries properly easy and let the heart rate come down. One high speed session a week is plenty. Anything else of intensity shouldn’t really be much more than tempo – or 7/10 effort.

Everyone has their favourite sorts of interval session. I’d love to know what yours is!

Send us a message or leave a comment and let us know if you have any questions! We all have our own thoughts on the matter, and we all have something different that suits us.

See what’s up next week for our #RunFormFriday tip! For more in-depth understanding on how to put this into practice, get in touch and we’ll see how we can help!


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