We are not talking about your threshold to pain (although pain can come into the equation). We are talking Lactate Threshold (LT), also known as Anaerobic Threshold (AT).

Your AT in very simple terms, is the point where Anaerobic energy metabolism (Glycolysis) begins to exceed the bodies ability to produce energy via Aerobic metabolic pathways.

The result is an increase in the production of Lactic Acid and Hydrogen ions (as a result of increased Anaerobic Glycolysis), which ultimately has a negative impact on performance.
It is important to note that the AT is not a point where there is a sudden onset of fatigue and other factors associated with increased concentrations of Lactic Acid [LA]. In fact, it is barely noticeable, because all that happens is a change in the % contribution from the Aerobic Pathways compared to the Anearobic Pathways.

Long Slow Distance ride:
When you are doing a 200km Long Slow Distance (LSD) ride, you are getting a majority of your energy from the Aerobic Lipolytic (Fat) and Glycolytic (Carbohydrate) pathways (90%), with a small contribution coming from the Anaerobic Glycolytic pathway (10%).

Criterium race:
A Criterium race would require more energy, at a faster rate to generate the Power outputs required during racing, which means that Anaerobic Glycolysis would be the dominant energy provider (50%-70%), with the Aerobic Glycolytic pathway still contributing to the bodies overall demand, but to a lesser extent (30%-50%).

Your Threshold is the point where Anaerobic Glycolysis contributes about 51% of the energy to your bodies total energy demand and your Aerobic pathway contributes 49% to the total demand.

So you can see that knowing where this Threshold point is located could have a large impact on you performance, because spending to much training time working above your Threshold can have dire consequences not only to your performance but to your health.

Excessive Training above the Anaerobic Threshold can result in:

  • Increased Acidosis which in turn leads to a reduction in your Aerobic Endurance capacity: This value remains reduced for a couple of days after the session.
  • High intensity training damages the muscles cell wall: This causes leaking from the cell into the blood, and many abnormal enzymatic values can e detected.
  • Muscle damage: Acidosis is the culprit for micro-ruptures in muscle fibers, and if there is not sufficient recovery time allowed, more sever muscle damage can occur.
  • During training, elevated [LA] leads to impaired Aerobic Lipolysis: Which means that the body no longer has the option of using Fats as an energy source, but becomes reliant on limited Carbohydrate stores.
Not quite as dramatic, spending to much time training below your Threshold will see your performance start to stagnate, and improvements becoming harder to achieve.

The key is find a good balance between Volume and the Intensity. Knowing where your Anaerobic Threshold is, is the first step to seeing improvements in performances.

In last weeks post, Where is your cycling fitness at right now?, I briefly touched on a few tests available to you, to help you set a baseline for future assessment.

AT testing is probably one test that will give you the most benefit and the most applications for your training and training program.

Next weeks posting will attempt to answer the following questions:
  1. How do you determine your AT?
  2. Can it determined without a lab test?
  3. How do you apply the results to your training and your program?

James Greenwood is a competitive tri and multisport athlete currently training for Ironman Canada 2009. A level 1 Triathlon Coach, he holds a post graduate degree in Exercise Science, and is a Certified Strength and Conditioning Specialist through the NSCA. James is also currently the resident health and fitness programs expert at MyPypeline.com, and has starred in a number of multisport specific fitness videos.
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