Lactate Threshold

Lactate Threshold 2016-10-24T03:50:54+00:00

Everyone wants to ride, run and swim faster. Whilst natural ability still plays a huge role, lactate threshold is highly trainable (as is Vo2Max). By training properly almost every individual can ramp up their lactate threshold.

 

What is Lactate Threshold (also known as anaerobic threshold)?

Lactate is a by-product of anaerobic metabolism that, despite common misconception, is produced across all exercise intensities. In fact, even when you stand up from sitting in a chair, lactate acid is produced. The key in sport is the balance between the rate of lactate production and lactate absorption.

During light and moderate-intensity exercise, the blood concentration of lactate remains low. The body is able to absorb lactate faster than the muscle cells are producing it. However, as exercise intensity increases, there comes a point at which lactate removal fails to keep up with the rate of lactate production. This point is referred to as the lactate threshold and spells the beginning of the end of high intensity exercise. 

Excessive blood lactate and hydrogen ion concentrations combine to interfere with efficient and proper muscle contraction, and as a result, power output drops, suffering increases and you are forced to slow down.

Lactate threshold represents the highest steady-state exercising intensity an athlete can maintain for prolonged periods of time (> 30 minutes).

Most coaches and sport scientists today recognize lactate threshold, or a derivative thereof, as one of the strongest predictors of endurance performance.

Lactate Threshold also serves as a very useful measure for the determination of training zones and the overall effectiveness of training programs.

 

How is Lactate Threshold Measured?

Lactate threshold tests typically are performed on a treadmill or bicycle ergometer. After an adequate warm-up period, the test starts at an exercise intensity corresponding to 50-60 percent of the test subject’sVO2MAX. Each stage lasts 2-6 minutes, allowing sufficient time for the subject to achieve steady-state heart rate, VO2, and lactate production. Blood samples taken towards the end of each stage determine blood lactate concentration (a simple finger prick does the trick). The workload increases in steps and the process is repeated until an obvious spike in lactate concentration occurs. Heart rate, power output or speed, and/or VO2 are recorded at each stage.

We measure blood lactate concentration in millimoles (mM) of lactate per liter of blood (mmol/L). Lactate threshold typically is expressed as a percentage of one’s VO2MAX or maximal heart rate. With the advent of power meters, various power outputs identify a riders lactate threshold and training zones. By evaluating a rider’s power output at lactate threshold, we can determine the potential for success. To be competitive in a race like the Tour de France, a male professional must be able to maintain 5-6 watts/kg at lactate threshold. This means if the rider weighs 68 kg (150 lbs) he must produce 350-400 watts while riding up even the toughest hills.

If you take two cyclists, one with a high VO2max but a moderate lactate threshold, and the other with a moderate VO2max but a ridiculously high lactate threshold. Being the same size and weight, the cyclist with the highest lactate threshold would likely find himself victorious in a head to head race up a monster hill.

It is possible to find your lactate threshold without going to a laboratory. A majority of cyclists could care less what their actual lactate threshold number is. What is important is how fast and long can they ride at a given workload.

Many applied exercise physiologists believe that finding your lactate threshold in the field is actually more applicable than finding it in the lab. What you can do while on a ride is a pretty good indicator of what you’ll be able to do on a ride. Sounds so simple you may think that last sentence was a mistake. No mistake, just simple common sense. There are a variety of techniques for finding your lactate threshold on the road.

It seems that each coaching system or training book has its own specific method. Although they vary a bit, most will give you an effective idea of your lactate threshold. Some are more complicated than others. For the sake of time and simplicity, one of the easiest techniques for finding your lactate threshold in the field is to use the following approach, using a heart rate monitor or power meter.

 

Finding Your Lactate Threshold

  • Find a flat or slightly uphill stretch of road (avoid undulations or hills)- you may also use a trainer (but this is mentally tough).
  • Warm up for at least 10-15 minutes.
  • Ride a thirty-minute time trial with your best possible time.
  • If using a heart rate (HR) monitor, record the last twenty minutes of your ride. – Your average heart rate over this period will estimate your HR at lactate threshold.
  • If using a power meter, record the last twenty minutes of your ride – Your average power over this period will estimate your power output at lactate threshold.

How Does Your Lactate Threshold Rate?

To put things in perspective, untrained individuals usually reach lactate threshold at about 60 percent of their VO2MAX.

Moderately trained athletes reach lactate threshold at 65-80 percent VO2MAX.

Elite endurance athletes have a very high lactate threshold relative to their VO2MAX. They are able to ride at 85-95 percent VO2MAX, and it is this ability that allows them to make a living riding bikes, running or both.

Your numbers can change. Lactate threshold is not as fixed as VO2max. Through proper training and commitment, an athlete can increase the percentage of VO2max at which their lactate threshold occurs. What fantastic news! Finally, something an individual can control. Through years of hard work and training, a person can become an athlete who is able to perform at near maximum for extended periods of time.

 

Factors that Affect the Rate of Lactate Accumulation

There are numerous factors that change the rate at which lactate is produced.

  • Exercise intensity. The harder you work, the more lactate your active muscles produce.
  • Diet. If you don’t have good stores of glycogen, your high intensity training will be short lived.
  • Training status. Proper training develops four primary mechanisms to slow the rate of lactate accumulation:
    1. Higher mitochondrial density allows for greater lactate resynthesis.
    2. Superior fatty acid oxidation prevents lactate production at submaximal exercise intensities. Your body will preferably burn fat over glycogen and this will preserve your glycogen as a fuel source for continued exercise.
    3. Greater capillary density improves both oxygen delivery to and lactate removal from the active muscles.
    4. Muscle fiber type composition. Slow twitch (Type I) muscle fibers produce less lactate at a given workload than fast twitch (Type II) muscle fibers. Although there is a big genetic component, proper training can influence the proportion of slow vs. fast twitch muscle fibers.
  • Distribution of workload. A large muscle mass working at a moderate intensity will produce less excess lactate than a small muscle mass working at a high intensity. Certain cycling techniques will slow the overall accumulation of lactate by using different muscles.

What does it all mean?

We have said that lactate threshold is one of the strongest predictors of endurance performance. So, if you increase your lactate threshold, you will be able to swim/bike/run faster and put the hurt on your friends and fellow competitors. To quote an analogy from a well known endurance coach, “It’s not only the size of your magic wand (VO2max), but how your wield it (lactate threshold).” If you train properly, you can have dramatic increases in you lactate threshold.

 

So, how do we train properly to increase lactate threshold? Well, that’s a whole other story…