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What is Lactate Threshold Training?
You may over-hear runners talking about doing lactate threshold training or tempo runs. They may call an 8 miler that they run at a harder than usual pace a tempo run.
In this first article of three on lactate threshold training, I want to look at what this really is, to help you better understand the term. In the second article, I subsequently will look at how it relates to running economy, and how to determine your threshold.
In the third article of this series, I will consider how to improve your lactate threshold, and therefore how to race smarter – so stay tuned!
If you read my post on VO2 max you will know that for performance in 5km races, this is the most important physiological attribute. However a high lactate threshold is still important. For races longer than 10k, lactate threshold (LT) is the most important factor in determining running performance.
Defining Lactate Threshold
Your lactate threshold (LT) determines how fast you can race. When you select a race pace you really are selecting a pace that prevents an excessive accumulation of lactate (a by-product of the carbohydrate metabolism). When resting, walking or running easily the amount of lactate in your blood remains low and relatively constant as rate of production = rate of removal. When you exercise above a certain intensity the rate of lactate formation is greater than the clearance rate so the concentration rises in your blood and muscles. This is your lactate threshold, the exercise intensity above which lactate clearance can no longer keep up with lactate production.
Understanding Lactate Threshold
An investigation into changes in VO2 max and running performance with training (Daniels 1978) found that running performance continued to improve after VO2 max ceased to improve. That is because you can continue to boost your lactate threshold long after you’ve maximised gains in VO2 max. For Veteran runners this is great news!
Oxygen consumption at the LT is known as LTVO2. During the recent past research has shown that LTVO2 and it’s associated pace (LT Pace) is more accurate than VO2 max in predicting distance-running performance. In studies (for example Farrell et al 1979) higher correlation was shown to occur between LT measurements and endurance performance than between VO2 max and endurance performance because VO2 max primarily reflects the ability of the heart to transport oxygen to the muscles whereas the lactate threshold also reflects adaptations in the muscles that increase the capacity of those muscles to produce energy aerobically. For the triathletes reading then remember triathlon is an aerobic sport! This LT Pace is determined by only two factors: your oxygen consumption at LTVO2 and your running economy.
To illustrate the advantage of high LTVO2 and how this relates to pace let’s consider two runners with identical VO2 max values of 60 ml/kg/min but different LT. Athlete A’s LTVO2 occurs at 48 ml/kg/min (80% of VO2 max) whilst Athlete B’s LTVO2 occurs at 42 ml/kg/min (70% of VO2 max). If the runners race at a speed that requires 45 ml/kg/min then Athlete A will be able to maintain the pace but Athlete B will have to slow down.
LTVO2 isn’t the answer by itself, however because we don’t all use the same amount of oxygen at a given speed. Just as some cars consume petrol and some drivers drive more economically than others, some runners are more economical than others in consuming oxygen. In the next article we will look at how to determine your lactate threshold.
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