Lactate Threshold (Tempo) Runs

Objective – to increase your Lactate Threshold Point so you can make more use of lactate energy before fatigue caused by too much lactic waste occurs.

When we run we use all three of our energy systems. One of these three, the lactate energy system, produces waste product that your body can deal with, but only up to a limit. When the amount of waste product being produced exceeds the rate at which your body can deal with it, you have reached the Lactate Threshold and you will fatigue rapidly (Heavy legs; Hit the Wall).

Think of a bathtub with an open plughole. When you are running hard you will use your lactate energy system, which creates waste product that goes into the bathtub and will continuously drain out of the plughole. Run harder and you will create more waste product. Run harder still and you will reach a point when the production of waste product will be greater than the plughole can deal with and the bathtub will fill up. Once the bathtub overflows you will be finished, as your body will ‘hit the wall’, which  is very difficult to recover from without rest. When racing, the objective is to use as much lactate energy as you can so the bathtub fills up, but to ensure the plughole is big enough for the bathtub not to overflow. Tempo runs help you increase the size of that plughole!

The intensity of a tempo run is such that your bathtub is just below the overflow point of the bathtub, putting most pressure on the plughole to grow.

Many runners fail to run fast enough in a Tempo run.  The LT pace is what matters and can be roughly measured by race times:-

  • For experienced runners, LT pace is that you could race at for one hour without stopping
  • For faster experienced runners, LT pace is race pace for 15k
  • For elite runners, LT pace is somewhere between race pace for 15k to half marathon
  • For those who usually run shorter distances, LT pace is about 6 to 10 secs slower than 10k race pace or 12/18 secs slower than 5k race pace
  • Or using heart rates, LT pace is the heart rate when we are running at 15k race pace, or racing for one hour

There is some uncertainty about the most effective way to improve the pace you can reach before hitting the LT. Several examples are given and it will have to be up to you to find our which one works best.

Traditional Tempo Runs – Start with a 20 minutes easy jog, then run continuously for 20 to 40 minutes at your LT pace, then a cool down jog.

Revised Tempo Runs – Start with a 20 minutes easy jog, then run continuously for 20 to 30 minutes at 6 secs per km faster than your LT pace, then a cool down jog.

Changing Pace Tempo  Runs – Start with a 20 minutes easy jog, then run continuously for 20 to 44 minutes at two different rates, broken into 4 minute segments. The first 4 minute segment at 10 secs per km faster that LT pace, followed by a 4 minute segment at 6 secs per km slower than LT pace. Alternate fast/slow segments for between 20 and 44 mins then take a cool down jog.

Hills and Lactate Threshold Tempo Runs

We live in a hilly area, so use long hills (for example Sparrowsend Hill in Saffron Walden) as a Tempo run. Push on the uphill at your LT pace and keep going for an additional minute on the downhill.

As Tempo runs are based around your race pace, they are uncomfortable. You will be out of breath. If you are not, then you are probably not going fast enough. One tempo session per week is sufficient.

Graeme Loudain – September 2019

These notes are published as a general aid to all endurance runners. They are guidelines based on current best practice, intended to illustrate the points in the articles rather than provide a precise training schedule. They are written in a way to be of help to runners. Individuals will have their own requirements and the content of the notes will not suit all. Please use them in the spirit in which they are intended and modify them to suit your own needs. If you have suggestions for improvement, amendments or comment, please email