Endurance training


Endurance training is the act of exercising to increase endurance. The term endurance training generally refers to training the aerobic system as opposed to the anaerobic system. The need for endurance in sports is often predicated as the need of cardiovascular and simple muscular endurance, but the issue of endurance is far more complex. Endurance can be divided into two categories including: general endurance and specific endurance. It can be shown that endurance in sport is closely tied to the execution of skill and technique. A well conditioned athlete can be defined as, the athlete who executes his or her technique consistently and effectively with the least effort. Key for measuring endurance are heart rate, power in cycling and pace in running.

Endurance in sports

Endurance training is essential for a variety of endurance sports. A notable example is distance running events with the required degree of endurance training increasing with race distance. Two other popular examples are cycling and competitive swimming. These three endurance sports are combined in triathlon. Other sports for which extensive amounts of endurance training are required include rowing and cross country skiing. Athletes can also undergo endurance training when their sport may not necessarily be an endurance sport in the whole sense but may still demand some endurance. For instance aerobic endurance is necessary in racket sports, football, rugby, martial arts, basketball and cricket. Endurance exercise tends to be popular with non-athletes for the purpose of increasing general fitness or burning more calories to increase weight loss potential.

Physiological effects

Fundamental for endurance training is supercompensation. Supercompensation describes the adaptation of muscles on a previous stimulus over time.
Long-term endurance training induces many physiological adaptations both centrally and peripherally mediated. Central cardiovascular adaptations include decreased heart rate, increased stroke volume of the heart, increased blood plasma, without any major changes in red blood cell count, which reduces blood viscosity and increased cardiac output as well as total mitochondrial volume in the muscle fibers used in the training. Changes of the hormonal regulation can be observed. Endegenous insulin secretion is increased, as well as the insulin sensitivity of muscle cells raises and glucose tolerance raises. Moderate sporting activity strengthens the immune system and reduces proneness to infection. Improved performance capacity and improvement handling of daily life needs could be observed. The aging process could be slowed down by training. Increased life expectancy of at least two years could be observed. Mitochondria increase in both number and size and there are similar increases in myoglobin and oxidative enzymes. Adaptations of the peripheral include capillarization, that is an increase in the surface area that both the venous and arterial capillaries supply. This also allows for increased heat dissipation during strenuous exercise. The muscles heighten their glycogen and fat storing capabilities in endurance athletes in order to increase the length in time in which they can perform work. Endurance training primarily work the slow twitch fibers and develop such fibers in their efficiency and resistance to fatigue. Catabolism also improves increasing the athletes capacity to use fat and glycogen stores as an energy source. These metabolic processes are known as glycogenolysis, glycolysis and lipolysis. There is higher efficiency in oxygen transport and distribution. In recent years it has been recognized that oxidative enzymes such as succinate dehydrogenase that enable mitochondria to break down nutrients to form ATP increase by 2.5 times in well trained endurance athletes In addition to SDH, myoglobin increases by 75-80% in well trained endurance athletes.

Risks of excessive endurance training

The potential for negative health effects from long-term, high-volume endurance training have begun to emerge in the scientific literature in recent years. The known risks are primarily associated with training for and participation in extreme endurance events, and affect the cardiovascular system through adverse structural remodeling of the heart and the associated arteries, with heart-rhythm abnormalities perhaps being the most common resulting symptom. Endurance exercise can also reduce testosterone levels.

Methods and training plans

Systematic training is the key for good results. Common methods for training include periodization, intervals, hard easy, long slow distance, and in recent years high-intensity interval training.
Traditionally, strength training was not deemed appropriate for endurance athletes due to potential interference in the adaptive response to the endurance elements of an athlete's training plan. There were also misconceptions regarding the addition of excess body mass through muscle hypertrophy associated with strength training, which could negatively effect endurance performance by increasing the amount of work required to be completed by the athlete. However, more recent and comprehensive research has proved that short-term strength training in addition to endurance training is beneficial for endurance performance, particularly long-distance running.
Literature describes following forms of endurance exercise

Devices to assess endurance fitness

The heart rate monitor is one of the relatively easy methods to assess fitness in endurance athletes. By comparing heart rate over time fitness gains can be observed when the heart rate decreases for running or cycling at a given speed. In cycling the effect of wind on the cyclists speed is difficult to subtract out and so many cyclists now use power meters built into their bicycles. The power meter allows the athlete to actually measure power output over a set duration or course and allows direct comparison of fitness progression. In the 2008 Olympics Michael Phelps was aided by repeated lactate threshold measurement. This allowed his coaches to fine tune his training program so that he could recover between swim events that were sometimes several minutes apart. Much similar to blood glucose for diabetes, lower priced lactate measurement devices are now available but in general the lactate measurement approach is still the domain of the professional coach and elite athlete.