Muscles are made up of muscle fibers. The fibers consist of different filaments, and proteins. The most important are actin and myosin that allow muscle contraction. Man has two types of muscle fibers.
Type I – Slow fibers (ST)
They have better endurance capability as a result of more capillaries and mitochondria, which are important for oxygen delivery. They therefore take place more easily done aerobically (= aerobic presence of oxygen)
Type II – Fast fibers (FT)
Fast fibers are thicker, have more myofibrils and therefore greater power. They also have higher glycogen under anaerobic important storylines. They are capable of producing more power and speed than slow fibers but tire easily.
Type II is subdivided into
Type IIA (oxidative – glycolytic) as the name suggests are the oxidative ability, so they are anywhere between fibers I and II. under the influence of different training to adapt and acquire endurance or speed characteristics
.
Type IIB (glycolytic) are custom fast fibers
Recently, Taking a slow and fast motor units. The neuron motor unit (basic functional unit of the nervous system that leads Info from the nerve centers to the muscles) and muscle fibers which, innervate. It can be up to several hundreds of fibers. One motor unit is made up of only one type of fiber (I or II), the neurons of slow units are easily aroused sufficient weaker stimulus was, therefore, engage with the mild action. Work will last for long.
Quick neurons have a higher threshold for arousal, so they need stronger stimulus – is activated only when necessary to develop the maximum speed or power, but keeps working only briefly.
The ratio of slow and fast muscle fibers, for each inherited. Training must be to increase the number of threads but the ratio remains. Therefore, someone more endurance type or speed. Of course this can be to some extent affect the type of training – IIA fibers are adapted.
With age, decreasing the number of fast fibers mainly because they lack incentives to work. Commonplace activities are activated mostly just slow fibers.
Also, the ratio of fibers in the various muscles is different.
