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Prevent Fatigue With Lactate Threshold Training

By Rick Morris

The best way to improve your running performance and fitness is to raise your lactate threshold.

You’re well into your daily run and your legs are feeling heavy and nonresponsive. You’ve lost most of the “pop” or power in your stride. It’s getting difficult to maintain your running rhythm and stride rate. That “big ol’ bear” has just jumped on your back again. Does that situation sound familiar? If you are an experienced 5K or 10K runner, you have certainly felt those unpleasant sensations during the final miles of your races. Why? Because you’ve crossed that vague and imprecise barrier that is known as your lactate threshold or anaerobic threshold.

During running, or any other physical activity, one of the ways your body produces energy is through a process called glycolysis. During this process, a substance called lactic acid is produced. At low running speeds, your body will process and use that lactic acid to produce even more energy. When you increase your running intensity, more and more lactic acid is produced. Eventually, lactic acid is produced so fast that your body can no longer keep up. The lactic acid begins to build up. This point is your lactate turn point, or lactate threshold.

Not too long ago, it was believed that the accumulation of lactic acid was the cause of those unpleasant feelings of fatigue in 5K and 10K races. The latest research has disproven that theory. Now it’s thought that lactic acid actually helps prevent fatigue. There are other changes that take place in your body at your lactate turn point that contribute to fatigue. Hydrogen ion build-up, extracellular potassium accumulation, calcium leakage, and central nervous system protection mechanisms are all fatigue-inducing processes that take place at your lactate turn point.

Why You Need Lactate Threshold Training

If lactic acid isn’t the primary cause of fatigue, do you still need lactate threshold training? Yep – you absolutely do. While lactic acid accumulation may not be the direct cause of fatigue, the processes which cause high-intensity running fatigue still take place at the same point – right at your lactate threshold. At this point, science still doesn’t have a concrete answer to the precise causes of running fatigue – just a lot of theories. But most agree on one thing: the best way to improve your running performance and fitness is to raise your lactate threshold. The best way to improve your lactate threshold is by training at a pace that flood your body with lactic acid. That means training at or near your 10K pace.

Tempo Training or Lactate Threshold Training?

A common mistake made by many athletes is lumping together tempo training and lactate threshold training. True tempo training is performed at paces between 45 and 15 seconds slower than the 10K race pace, while true lactate threshold training is done at paces faster than the 10K pace. So why are the two often lumped together? There are a couple of reasons for that.

First: for many years, tempo training was considered the best way to improve lactate threshold. The tempo run became the staple workout for lactate threshold improvement. Habits are hard to break, so many runners still rely too much on tempo training.

Second: tempo training still is a form of lactate threshold training, albeit at the lower end of the lactate threshold spectrum. The slower pace of tempo training is not an ideal running intensity for lactate threshold improvement. Running at a 10K pace or faster is required to maximize your lactate threshold improvement. But the high intensity of lactate threshold training makes it impossible or at least inadvisable to perform long repeats on a consistent basis. That is where tempo running becomes an extremely valuable workout.

The more moderate pace of tempo running allows you to complete longer training runs at a pace that still gets your glycolytic system operating at a high level. So you need both tempo training and lactate threshold training to maximize your fitness level. Tempo training will improve your stamina, while lactate threshold training will maximize lactate turn point improvement.

Lactate Threshold Workouts

One of the great things about distance running is you can design an unlimited number of different workouts. You should never be bored! Here are just a few lactate threshold treadmill workouts that will make your lactate threshold soar along with your fitness level. For each of these workouts, set your treadmill incline at 1 percent or level 1. Make sure you warm up with around 5 to 10 minutes of easy treadmill running before your beginning these workouts.

Each of these workouts is based upon a 10K race pace. If you don’t know your 10K pace, you can monitor your speed using either your perceived exertion level or your heart rate. Your heart rate at 10K pace should be around 85 percent of your maximum heart rate. If you use your perceived exertion, your workout should feel moderately hard or about a level 7 to 8 on a scale of 1 to 10, with 1 equalling sitting in a chair and 10 equalling all-out effort.

30-Minute Tempo Run

This one is a very simple but enjoyable and effective training run. After a brief warm-up, run for 30 minutes at about 20 seconds per mile slower than your 10K pace. Your heart rate should be at around 80 percent of your maximum heart rate. You should feel like you are running at a moderate to moderately hard pace, or about level 7 on the perceived exertion scale.

One-Mile Repeats

This is a very basic lactate threshold interval run using mile repeats. After a warm-up, run six 1-mile repeats at 10K race pace. Recover between each repeat with 2 minutes of rest or easy jogging.

6 x 400/1200 Meter Compound Sets

This workout combines running at two different speeds and is perfect for your treadmill. Warm up and then run 400 meters or one-quarter mile at a very hard, almost maximal pace. With no recovery, slow down to 10K pace for 1,200 meters or three-quarters of a mile. Recover with 2 minutes of easy jogging. Repeat five more times for a total of six compound sets.

Happy Treading!