Speedwork, the Necessary Evil to Performance - Benefits, Timing and Pacing

I was having lunch last week with one of my colleagues, who is a recreational runner running up to 10k on a regular basis. We were talking about me logging progressively heavier mileage and my 2019 goal of both a Boston-marathon qualifying time and a 100k ultra marathon, admittedly two extremely different goals within 3 months of each other. My colleague commented that he had no wish to run any more than 10k (fair enough, I do completely get the fact that long distances do not appeal to everyone!), but that he thought he couldn’t get any faster than his 50min PB. Ok. But then we started talking about speedwork, the likes of 800m repeats and then he said that he didn’t understand how running shorter distances at a faster pace could get you faster over longer distances. Uh? I thought it was obvious that to run FASTER you need to run FASTER (regardless of distance)? But then I realised that maybe there were actually quite a lot of recreational runners who didn't fully understand what speedwork was and what the benefits of it were. So there I thought I could write a little piece on this. I must admit to learning some new facts in the process of researching this myself, especially in terms of timing in periodisation, so hopefully you will also find this post useful.

What Is Speedwork And What Are The Benefits?

Speedwork is a broad term that describes any workout where you push yourself to run faster than your easy pace (where you can hold a conversation). It covers anything from a higher aerobic pace (say, your marathon pace) to working out in the anaerobic range (if you want to understand the difference between working out in the aerobic range and in the anaerobic range, this article gives a pretty simple but good explanation).

Now, why should you be interested in doing any speedwork? Speedwork has two main benefits: it increases your aerobic capacity, and it also helps optimise the use of your glycogen stores (pretty essential for longer distances as it means you can go further before hitting the wall). It also helps training your fast-twitch muscles, which will be mobilised when your slow-twitch muscles have had enough. You can find further details on these various aspects in this very good post.

What Are The Different Types Of Speedwork?

There are a variety of types of speedwork, and they all have slightly different purposes.

Fartlek:

The name comes from Sweden, where it means “speedplay“. As the name suggests, it is not a structured workout, but about having a bit of fun when running faster. You can pick a point in the distance and run hard until you reach that point, then recover with a recovery jog and then repeat further down your route. It’s a nice way for runners new to speedwork to ease into it.

Tempo:

Tempo is defined as a run at a given target pace, but that pace can vary from aerobic pace to anaerobic threshold depending on your race distance. For example, if training for anything above a 10k you are better off doing a tempo training run in the aerobic zone. For shorter races like 5k or less you may want to perform your tempo run at your lactate threshold (or anaerobic threshold) so this will be performed at a faster pace.

Intervals:

Usually intervals will be repeats of shorter distances like 200m to mile repeats at much faster pace like 5k pace or above. The main difference with tempo and fartlek is that they include recovery breaks in between repeats. The length of the breaks can vary depending on the distance but are typically in the order of 1 to 2 minutes.

When Should I Be Doing Speedwork?

Speedwork should preferably be introduced after a solid endurance (aerobic) base has been gained. This is not only to prevent injury but also because any large and frequent increases in lactic acid (as encountered if including significant speedwork in your programme) will damage the mitochondria and aerobic enzymes produced during your base training and necessary to an efficient aerobic energy system.

What Pace Should I Be Running My Speed Workouts At?

As mentioned above the pace of your speedwork will depend on your race distance, which will dictate whether you need to train in the aerobic or anaerobic range.

Anything above 10k should incorporate most training in the aerobic range (including tempo runs close to lactate threshold, i.e. at about 10k race pace), whilst for 5k or less shorter intervals in the anaerobic range will be more beneficial.

For a guide of training paces, see the McMillan calculator.

Happy running!