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Interval Sessions and Speed Work

This explanation is for beginners and those who have never tried interval training.

These are the most important element of training for track runners but they also play a really important role at all distances, even ultra runners. An interval session is essentially breaking up a run into segments with recoveries between each segment. This means you can run much faster than during a single continuous run. A variety of paces and durations of recovery are used. We refer to the running part as the repetition and the recovery between each repetition is the interval. We often group repetitions into to sets with longer rests between each set.


You will often run much faster than race pace and your lactic acid levels rise much higher than in other workouts. During an interval session you might also work close to or at your maximum effort. The idea is to increase the speed you can maintain over varying distances and we refer to this as speed endurance. We sometimes also work on improving maxim speed.


The methodology of internal training that we use we call multi pace chain theory and it’s similar to the five pace theory used by the well known coaches Frank Horwill and Peter Coe. The five pace theory is when you train at two additional paces either side of your main race pace. We have adapted the title to multi pace chain rather than five pace as there are more than five paces used in our sessions. Indeed the coaches that use five pace theory also used more than five paces in their training.

Here's an example of how five pace training might look for someone who's main event was 1500m.

Session paces 400m - 800m - 1500m - 3000m - 5000m

We can see that the 1500m runner uses two paces either side of their 1500m main event goal. As a 5000m or 10000m runner we often trained from maximal 30m sprints right though to 10000m race pace on the track and also some slower tempo / threshold cruise type reps. This was a lot more than five paces.  


The multi pace theory is underpinned by the fact that the various paces you run at all have a knock on affect right from your maximum sprint to the pace you can maintain in a marathon or beyond. The reason for this is due to the impact faster running has on your running economy at slower speeds. There are many physiological and neurological adaptations that contribute to this improved economy together with the changes in your running style or form.


Lactic acid levels will rise considerably higher during intervals and you will improve your ability to tolerate high levels of lactic acid. You will also be operating at close to and on occasion at your maximum heart rate. Some coaches use lactate monitors and/or heart rate to control the intenisty of their sessions. We occasionally used a mixture of these methods but mostly did sessions without monitoring heart art and/or lactate.


It’s very important to balance your mix of interval sessions so that they ultimately support improvement over the specific race distance. To do this you must run over a range of paces and distances but an emphasis is placed on certain paces. Additionally, for serious racers, you might also work on additional attributes such as change of pace to cover surges during a race, your ability to kick and your finishing speed. We use various methods to achieve this including differentials. An example of a differential is an 800m rep where you run the first 400 at say 5000m pace and the second 400m at 1500m pace. We also do pick ups and actual surges during sessions to practice other racing attributes. If you want to see this in action have a look at the 2004 Women's Olympic 5000m Final on YouTube. You will see lots of slow laps, fast laps and surges. By being able to cope with fast laps and surges Jo was able to finish ahead of runners who had quicker personal bests including the world record holder at the time. This illustrates the importance of training to race!

Examples of interval sessions:



This means repetitions of ten times four hundred metres with forty five seconds of recovery between each repetition. 



This means two sets of eight times four hundred metres with thirty seconds of recovery between each repetition and five minutes rest between each set. 


We use the notation of lower case r for recovery in seconds and higher case R for minutes. We also use brackets to denote recovery and square brackets to denote rest between sets.

Both rest and recovery can be static where you are stood or active when you jog slowly, or a combination of both. This is denoted as follows: 10x400m(45j). This denotes a 45 second jog.


Here are some examples of the types of sessions we use:



                Track, Road, Off Road/Trail (used throughout the year)



                Road, Off Road/Trail (mostly used in winter)



                Road, Off Road/Trail (used in winter and through to early summer)


        Mixed Tempo Intervals

                Track, Road, Off Road/Trail (used throughout the year)


During the recovery phase in a session your body will be working hard to bring everything back to resting levels. Lactic acid clearance continues and can even rise further during recovery, the heart rate gradually drops, etc. This respite from the intense running is what allows you to continue with the intensity for longer durations than a single continuous run at the same intensity would allow.

The recovery and rest periods between reps and sets are really important as together with the overall number of reps being run they will determine what pace you can run at. This is best explained with an example.


5x1000m (90r)

Due to the relatively short 90 second recovery these 1000m reps will be run at round 5k pace.



Due to the slightly longer 3 minute recovery these 1000m reps will be run at around 3k pace.


You can see that the session is the same with only the recovery changed. The increased recovery allows for a faster pace. 


During sessions we will sometimes run at one pace as in the above examples or sometimes we’ll use multiple paces. 


4x400m (60r) [5R], 5x1000m (90r) [5R], 4x200m (60r)


With this example I have varied the pace by altering both the recovery and distance.

The 400m reps with 60 seconds recovery will be run at about 1500m pace, the 1000m reps with 90 seconds recovery will be run at about 5k pace and the 200m reps with 60 seconds recovery will be run at about 800m pace. 


As the athlete goes up in race distance then the volume of the interval sessions tends to increase. So for instance, when primarily racing 5k many of Jo’s sessions were between 7k and 8k in overall volume. When she moved up to the 10k her sessions were more like 8k to 10k in overall volume. Although as a 5k runner Jo would still do some 10k volume sessions, and likewise as a 10k runner she would do some very fast low volume sessions.


Due to running more than one session a week we would shift the emphasis on each of the sessions. So for example on the first session of the week we might do something like: 2x5x1000m(60r)[5R] which will be a good 10k race pace workout. Then the second session of the week might be something like: 2x8x400m(30r)[4R] - [5R]4x200m(60r). This session has 400m reps with short recovery but Jo is typically able to run them at between 5k and 3k pace. After the 400m reps are completed we might take a slightly longer break of say 5 minutes and then some fast 200m reps for speed. These will be run slightly fatigued but with the aim to run at 800m pace.

As the year progresses the emphasis of the sessions will change with more orientation towards volume in the winter and faster work in the summer. Many coaches split their year into distinct blocks using a method called periodisation. This is the more traditional approach with higher volume winter training and lower volume faster training in the summer. We use a much more subtle form of periodisation and do not use this more traditional approach as we like to maintain various paces throughout the year. This approach results in increased running economy throughout the year, improves the overall quality of winter training and it means we don't let go of the previous annual cycle gains for the sake of it. We also carry the volume much deeper into the summer than most athletes and race far less. However the volume falls very low in the final month prior to a major championship. Coaches all have their own methods!

We hope this simplified explanation helps. Can I finish by saying that although interval training might sound like very tough training it can be lots of fun!

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