Written by Teemu Virtanen
Source material by Wikipedia, Polar, Active.com
Last week, I wrote an article about endurance and what the term actually means. Since Visma Ski Classics is a fine example of an endurance sport, it made sense to take a closer look at the word itself and define what endurance truly signifies. Now, let’s continue on the same path and analyze the aerobic and anaerobic thresholds, which are important terms when discussing about any endurance sport, and briefly describe three key training methods to increase one’s lactate thresholds. Of course, our pro athletes are very familiar with these terms and training methods, but it never hurts to refine one’s knowledge.
Generally speaking, aerobic threshold is a steady-state effort that you could perform for hours. At this range, you should feel like you can go on for a long time and you never feel like you are out of breath. In scientific terms, aerobic threshold is the level of effort at which anaerobic energy pathways start helping out with energy production. For endurance athletes, having an increased aerobic threshold is key for being able to go longer and further.
During aerobic metabolism, your body creates energy by burning carbohydrates and fats in the presence of oxygen and produces carbon dioxide and water as by-products (breathing and sweating). Most of our daily activities are fueled by aerobic metabolism.
The anaerobic threshold (AT) is the exertion level between aerobic and anaerobic training. The AT is the point during exercise when your body must switch from aerobic to anaerobic metabolism. The AT is a useful measure for deciding exercise intensity for training and racing in endurance sports.
Anaerobic metabolism kicks in when exercise intensity is greatly increased, and the aerobic system can no longer keep up with the body’s energy demand. This is the point at which we cross the AT. During anaerobic metabolism, the body burns stored sugars to supply the additional energy needed, and lactic acid is produced faster than it can be metabolized. Muscle pain, burning and fatigue make anaerobic energy expenditure difficult to sustain for longer than a few minutes.
The fitter you are, the longer you can fuel your body with the aerobic system before the anaerobic system needs to take over. You can improve your aerobic efficiency—and thus raise your AT—by doing high-quality aerobic work at a level just below your current AT.
When training long distance skiing, and in particular when increasing the aforementioned thresholds and thus improving your aerobic and anaerobic efficiencies, we can easily point out three main core exercise types; interval training, speed play (fartlek) and aerobic & anaerobic workouts.
Interval training uses different work and rest periods allowing the body to temporarily exceed the lactate threshold at a high intensity, and then recover (reduce blood-lactate).This type of training uses the ATP-PC and the lactic acid system whilst exercising, which provides the most energy when there are short bursts of high intensity exercise followed by a recovery period.Interval training can take the form of many different types of exercise and should closely replicate the movements found in the sport being trained for, in our case long distance skiing.
Speed play (fartlek) training
Fartlek and interval training are similar, the main difference being the structure of the exercise. Fartlek is a Swedish word, meaning speed play. This type of training is a combination of continuous (generally aerobic) and interval training (generally anaerobic), involving consistent changes of pace/intensity throughout the session.
Aerobic and Anaerobic training
To build your aerobic shape, you need to do a lot of long distance training with low intensity. And for increasing your anaerobic capacity, you need to do specific sprint workouts with maximum or near maximum speed. It is important to understand the difference between lactate threshold and lactic acid. Aerobic training will not help with lactic acid tolerance, however, it will increase the lactate threshold. The body will build a better tolerance to the effects of lactic acid over time during training. Anaerobic training improves the muscles’ alkaline reserves, allowing the muscles’ ability to work in the presence of increased lactic acid. Training at or slightly above the intensity where this occurs improves the lactate threshold.