What is a Lactate Threshold Test
Why Is Running Performance Testing Important?
Running performance depends on many different factors. These include V̇O₂max, lactate threshold, running economy and the ability to maintain a certain pace for a long period of time (Joyner & Coyle, 2008).
However, two runners with similar race times may respond very differently to the same training pace. For one runner, a pace of 5:00 min/km may feel comfortable and easy to maintain. For another runner, the same pace may be close to their threshold and much harder to maintain. This is where performance testing can be useful.
Instead of using general formulas to estimate training zones, testing allows us to measure how each body responds as running intensity gradually increases.
The two major methods are blood lactate testing and cardiopulmonary exercise testing.
Lactate Curve & Lactate Thresholds
Lactate is naturally produced by the body, even during easy exercise. As running intensity increases, blood lactate levels also begin to increase. During a lactate test, the runner completes several stages on a treadmill at gradually increasing speeds. At the end of each stage, a small blood sample is taken to measure blood lactate concentration. These results can then be plotted against running speed to create a lactate curve.
The shape of this curve helps us understand how the runner responds to different exercise intensities (Faude et al., 2009). Two important points can usually be identified.
The first lactate threshold (LT1) represents the point where lactate begins to rise above its lower levels. This is generally around the transition between easier aerobic running and more demanding exercise.
The second lactate threshold (LT2) occurs at a higher intensity, where blood lactate starts increasing much faster. Running above this intensity becomes progressively harder to maintain for long periods.
These thresholds can then be linked to the runner's heart rate and running pace.
Why Does the Lactate Curve Matter?
One of the main benefits of a lactate test is that the results can be directly connected to running. For example, testing may show that a runner's first threshold occurs around 5:10 min/km and their second threshold around 4:25 min/km. This gives the athlete more individual information than simply using general heart rate formulas.
The results can help guide:
Easy and zone 2 runs
Long runs
Threshold sessions
Interval training
Race preparation
Testing can also be repeated after a period of training.
If the athlete can run faster while producing a similar lactate response, this can indicate an improvement in endurance fitness. However, lower lactate is not always automatically better. The important information is how lactate changes as running speed increases.
Cardiopulmonary Exercise Testing
Cardiopulmonary exercise testing helps us understand how the cardiovascular and respiratory systems respond as exercise becomes harder. During the test, running intensity gradually increases while different physiological measurements are collected. One of the best-known measurements is V̇O₂max.
V̇O₂max represents the maximum amount of oxygen the body can take in and use during intense exercise. It is an important measure of aerobic fitness and is strongly related to endurance performance (Bassett & Howley, 2000). However, having a high V̇O₂max does not automatically make someone a faster runner.
Two runners can have a similar V̇O₂max but very different race performances. This can happen because performance also depends on factors such as running economy and how much of their aerobic capacity they can maintain during a race (Joyner & Coyle, 2008).
This is why V̇O₂max is more useful when it is considered together with other measurements.
Combining Lactate and Performance Testing
Combining different measurements gives us a clearer picture of the runner. During a graded treadmill test, we can connect:
Running Speed, Heart Rate, Blood Lactate and Aerobic Performance
From this information, we can identify important values such as:
First and second lactate thresholds
Heart rate at each threshold
Running pace at each threshold
Maximal heart rate
Maximal aerobic speed
V̇O₂max
Individual training zones
Data by themselves are just numbers. The goal is to turn these numbers into information that can help guide training.
Race results, training history, perceived effort, recovery and the runner's response to training are also important when planning a programme. Performance testing should therefore be viewed as another tool that helps coaches and athletes make better training decisions. Ultimately, the purpose of performance testing is simple:
To better understand how your body responds to running, identify the intensities that matter and use this information to make your training more individual and purposeful.
References
Bassett DR, Howley ET. Limiting factors for maximum oxygen uptake and determinants of endurance performance. Medicine & Science in Sports & Exercise. 2000;32(1):70–84.
Faude O, Kindermann W, Meyer T. Lactate threshold concepts: how valid are they? Sports Medicine. 2009;39(6):469–490.
Joyner MJ, Coyle EF. Endurance exercise performance: the physiology of champions. Journal of Physiology. 2008;586(1):35–44.
Midgley AW, McNaughton LR, Polman R, Marchant D. Criteria for determination of maximal oxygen uptake: a brief critique and recommendations for future research. Sports Medicine. 2007;37(12):1019–1028.