Runners often ask “What is a Tempo Run?”. The answers they get are always different, so this article gives you THE Tempo Run definition that you can actually use when your running plan says “Go for a Tempo Run”, and be sure that you are doing the best thing for your training.
- Tempo Run definition
- What is a Tempo run pace?
- What is the purpose of a tempo run?
- Threshold Run vs Tempo Run
- How do I find my Tempo Run pace?
- What heart rate Zone is a Tempo Run in?
- Different types of Tempo Runs
Tempo Run definition:
A Tempo Run is defined as “a run at an effort level just below where your legs start to burn”. If your legs feel burning, slow down. If they aren’t feeling any burn, speed up. Once you know where that boundary effort is, you can start to spot it in your regular Tempo Runs and stay just below it for maximum benefits. What’s more this is an easy definition, so if anyone asks you what is a tempo run, you can easily answer them now!
Read on to understand why this tempo run definition is relevant to your running training.
What is a Tempo run pace?
As you can imagine, given the above tempo run definition, the pace of your tempo run can change, both between runs, depending on how tired you are, weather, or other factors and within runs as you tire throughout the run. So how do you know what your tempo run pace is?
Let’s rephrase the question!
What is the PURPOSE of a Tempo run?
The purpose of a tempo run is to improve a runner’s ability to perform “Anaerobic Glycolysis”. This energy system breaks down Glucose (carbohydrate fuel stored in the muscles with water as Glycogen) without oxygen, to release ATP (chemical energy for muscles to fire). Anaerobic is the main energy system used when running for more than around 30 seconds, up to around three minutes. Beyond three minutes, the “Aerobic” energy system starts to dominate, but the Anaerobic system is still used significantly all the way up to three hour runs and more, so it is worth training for all endurance runners, not just for sprinters.
A by-product of the anaerobic process is Lactic acid, which is immediately broken down in the body into Lactate, during which a Hydrogen Ion is scooped up (and one is left behind). The Lactate is then moved from the fast twitch fibres to the slow twitch fibres, ready to be then moved from the slow twitch fibres back into the bloodstream, and back to the liver for Gluconeogenesis, turning the lactate back into Glucose for use in the anaerobic process again. They body is amazing. Hang on in there – there’s a reason this is important. I’ve summarised the process there, but click if you want more details of lactic acid in runners (opens in new tab).
To get better at Anaerobic Glycolysis, you have to run hard for a long time, but if you run too hard, your body cannot produce Lactate quickly enough, so the Hydrogen Ions aren’t scooped up by the Lactate and start causing a burning in the legs which tells you to slow or stop.
The more you do something, the better the body gets at it, so the optimum effort for getting better at Anaerobic Glycolysis is to run at a “Tempo” effort. That is an effort just below the point where your body can’t clear the Lactate and Hydrogen Ions quickly enough – this point is also known as the Lactate Threshold or Lactate Turn Point 2 or just “Threshold”. Running just below Threshold, you stave off the burning feeling and keep going for longer. For most runners who can run for an hour already, this effort level is around about their one-hour race pace effort. This one-hour effort is often touted as a tempo run definition, but without the additional pointer about legs burning, it’s incomplete.
If you run slower / easier, then less Anaerobic Glycolysis occurs and less Anaerobic Glycolysis adaptation occurs. If you run faster / harder, less time is spent training because you have to stop sooner due to burning in the legs, and less Anaerobic Glycolysis adaptation occurs. However, if you get the effort level bang on, then optimum Anaerobic Glycolysis adaptation occurs!
Threshold Run vs Tempo Run
Therefore a Tempo run is essentially a run at or close below Lactate Threshold. If you a wondering what the difference is between a Threshold Run and a Tempo Run, consider this: if you see someone referring to a “Threshold Run”, they mean a Tempo Run where you hover at Lactate Threshold effort level.
How do I find my Tempo Run pace?
So, whilst “hour race pace” is a good starting point for finding your tempo run pace / effort, the best method of getting Tempo pace / effort is to FEEL when the Ion buuuurn is starting and go a little slower than that. So now we are back to the simplest Tempo Run definition again! If you have no idea what pace to start trying with, then do a 5K race or time trial and then use our training pace calculator to give you an ideal starting point for your tempo run pace.
The more you practice, the easier it is to feel this burning sensation and what it feels like as you approach it. Don’t worry if you don’t get it right first time – that’s the point! You experiment with that boundary and learn its ways over many sessions.
What heart rate Zone is a Tempo Run in?
There are various heart rate zone models. In the 5 Zone HR model, a Tempo Run is somewhere in Zone 4 Z4, as long as it’s below Lactate Threshold. In the 7 Zone HR model, a Tempo Run is in Z4, but has been called “Sub-Threshold” (and a lower effort has been called “Tempo”, which does not match with my definition on this page, so careful if you are using the 7 Zone HR Model).
Different types of Tempo Runs
The reason there are different types of Tempo runs is that there are different ways of getting into and staying at that effort level. For example if you stayed at the same pace the whole way, you might go above the required effort (buuuurn), so you often see Tempo runs split up with rests or walks. Or Fartlek style. Or just a pace that slows slightly throughout the run, to stay at the right effort as the heart rate rises throughout.
Note: it takes a while for your heart rate to rise to the effort level required. So Tempo Runs require a warm up at the start, normally just easier running, to gradually get the heart rate up, before you start running harder to get the effort level up to the Tempo Run level.
As an aside, the best training to improve your body’s ability to move Lactate (and thus Hydrogen ions) from the slow twitch fibres, then into the blood for recycling and thus stave off that buuuuurn for longer is to do slow aerobic runs. So you can see how you have to do both tempo runs and slow runs to get faster! Read more about the need to run slow to run fast!
