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.
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 (i.e. the thigh muscles in runners will have more mitochondria than the thigh muscles of swimmers). Changes of the hormonal regulation can be observed. Endogenous 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.
Endurance training primarily work the slow twitch (type 1) 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 (SDH) 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.
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.
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.