Anaerobic energy threshold
We will briefly explain what happens to muscles during physical activity. This is important to understand because the terms 'anaerobic threshold' or 'aerobic training' are often used in everyday life, both in sport and recreational life. We would also like to clarify what slows us down and limits us in sports activities. We will particularly analyse what it is that can ruin our ski vacation.
Muscles operate using a special phosphate layer, adenosine triphosphate (ATP), which is situated in the muscle. There is very little ATP in the muscle (only for about 2 minutes of intensive muscular work) so it needs to be constantly regenerated. There are three ways of regenerating ATP in the body. The first method of ATP regeneration is by using another phosphate in the muscle, creatine phosphate (CP). It is also the fastest way of ATP regeneration. ATP and CP together make the so-called Phosphate Energy System. The Phosphate Energy System is always activated in the beginning of an activity when the body needs large amount of energy for movement, as well as during high-intensity activities. However, similarly to ATP, there are also relatively small quantities of CP in the muscles and just after 6-7 seconds of muscle work the maximum intensity of reserves of the CP is reduced by as much as 80%. It takes about 90 to 120 seconds of rest for phosphate sources of energy to return to their initial state. Certainly, athletes often have to work longer than just 6-7 seconds, sometimes even 30 seconds. In order to be able to do that, muscles have to transfer to another energy system, the so-called Glycolytic System. In this system, the energy muscles use carbohydrates in muscles (muscle glycogen) for energy production. In phosphate and glycolytic energy system, energy is released in the absence of oxygen. This way of generating energy is called anaerobic. Therefore, phosphate and glycolytic energy systems are together called Anaerobic Energy Systems. It is very important to emphasise that in the anaerobic glycolytic release of energy for muscle operation (anaerobic disintegration of carbohydrates) lactate is produced (lactic acid salts ) and some other compounds. A part of lactate remains in the muscles, while a portion is released into the blood which further travels towards the heart, mixing with the blood that comes from other (less active) body parts. There is, however, a limit in the intensity of load to which the formation of lactate in muscles and their removal and degradation from muscle are in balance, which is called the anaerobic threshold. Under the intensity of load at which the body is at the anaerobic threshold, an athlete can work without experiencing fatigue for longer periods. Nevertheless, if the work intensity is higher than the intensity in anaerobic threshold, there is an accumulation of lactate and other compounds in the muscles. This disables muscle work and leads to tiredness. Therefore, we are forced to reduce the intensity or even completely stop the activity under very high intensity that lasts over 30seconds.
In a large number of sports, the activities during a game are mostly of low and moderate intensity. During these activities, it is unnecessary to rapidly release large amounts of energy and muscles are then transferred to the third energy system, the so-called Oxidative System. In this system, the energy is released by the oxidation of carbohydrates and fat. Since the described process of obtaining energy takes place in the presence of sufficient amounts of oxygen, this energy system is called Aerobic Energy System.
Anaerobic energy threshold
Sport training activities
Individual sports activities