Cross-country skiing is undoubtedly an endurance sport, and long-distance skiing is one of its extremes. For skiers, endurance is a term we all know well, don’t we? Have we ever taken the time to think about what the word sustainability means? No worries, because this article tells you what endurance means physiologically.

In sports, endurance is the ability to maintain a particular activity for a long time, such as running, cycling, swimming, rowing, and cross-country skiing (the athletes must be able to continue a submaximal work rate for as long as possible). Naturally, psychology plays a crucial role in the success of endurance sports.

The primary factor that limits endurance exercise is fatigue. When fatigue reaches a certain point, the athlete’s work rate decreases, the exact moment at which fatigue limits performance (tolerance level) varies, and some athletes can tolerate much more fatigue than others. Although genetics and mental toughness contribute to fatigue tolerance, it can be practiced.

Fatigue is affected by several factors, such as cardiovascular endurance (the power of the heart and blood vessels), muscular endurance, aerobic endurance, anaerobic endurance, muscular strength, and mental toughness. These factors are certainly not strange concepts to those involved in endurance sports and skiing.

Cardiovascular endurance refers to the ability of our lungs, heart, and circulatory system to transport oxygen during prolonged exercise. Muscular endurance is the ability of a muscle or muscle group to use force for a long time. An athlete with good muscular endurance can repeat muscle contractions without tiring. These two essential endurance characteristics are an endurance athlete’s main components.

Muscles produce energy through aerobic (requires oxygen) and anaerobic (requires no oxygen) metabolism. During endurance sports, aerobic metabolism meets most of our energy needs. However, as the intensity of the exercise increases (such as in competitions or during power and interval training), anaerobic metabolism becomes relatively more important. At low intensities, we primarily recruit slow muscle cells. As the intensity of the exercise increases, the activation of fast muscle cells accelerates.

Aerobic endurance refers to the ability to produce energy through aerobic metabolism. The limiting factor here is the ability to absorb, transport, and utilize oxygen in energy production. Aerobic capacity can be measured by the efficiency of the lungs to inhale and absorb oxygen, by the efficiency of the muscles and especially the mitochondria to produce energy through aerobic metabolism, by the efficient transport of oxygenated blood around our body through the heart, and by the ability of our circulatory system and muscles to absorb oxygen from the blood.

Anaerobic endurance refers to our ability to work in situations where anaerobic energy systems play an increased role in energy metabolism. The term anaerobic means “without oxygen.” When the exercise intensity increases, the additional energy demand (power production) is met by fast muscle cells, which leads to an increase in anaerobic metabolism.

Although anaerobic metabolism can produce energy much faster, we always make compromises when using it. First, it leads to an increase in hydrogen ions in our bodies. This increases muscle acidity and can interfere with exercise performance. Second, it rapidly depletes muscle glycogen stores. Despite this, the development of anaerobic endurance is of prime importance in endurance sports such as skiing. In fact, it is essential to maximize performance potential, even though aerobic metabolism is our primary energy system.

Muscular strength is our ability to exert force during one maximal effort. It differs from muscular endurance because muscular strength is not dependent on time. Muscular endurance refers to the force exerted over time, while muscular strength relates to the maximum force you can use in a single performance. It is easier for an athlete with higher maximal strength to work at the maximal intensities required during endurance sports. The most important thing is to develop muscle strength without lifting weight, which in turn hinders the performance itself.

Mental toughness is one essential part that affects overall performance. Endurance athletes have the ability to resist the feeling of fatigue that forces us to slow down or stop during hard races or challenging workouts. Mental toughness develops over time as we are repeatedly exposed to fatigue during training, of course this is also partly an innate quality.

All athletes need some level of aerobic endurance. They also need to develop specific resilience. A good endurance base is essential for long-term development, regardless of the sport. It involves training all the components that affect performance. Sport-specific endurance refers to the development of particular targets required by the athlete’s chosen sport.

A skier’s basic endurance training, especially in the summer, includes a lot of low heart rate (aerobic) exercise for many hours to develop capillary blood vessels and increase muscle endurance. As fitness increases and the aerobic base is solid, the speeds can also be increased and varied in the basic runs to avoid excessive jolting – especially in sport-specific training on rollerskis. You can read more about training for a skier in our future articles.