Athletes need to understand muscle structure in order to select effective exercise and rapidly achieve hypertrophy. Learn strength training methodology. In the human body, it is customary to distinguish between three types of muscles: smooth, skeletal and cardiac. From the point of view of bodybuilding, skeletal muscles are of interest to us. Today we're going to talk about modern strength training in bodybuilding and start with muscle building.
Skeletal muscle structure
The main element of the muscles is the cell. Muscular tissue cells differ from others in their oblong shape. Let's say a biceps cage is about 15 centimeters long. For this reason, they are also called fibers. A huge number of capillaries and nerve fibers are located between the muscle fibers. The mass of these elements averages about 10 percent of the total muscle weight.
Approximately 10-50 fibers are connected into bundles, which, as a result, form skeletal muscles. The ends of the muscle fibers are attached to the bones by tendons. It is through the tendons that the muscles can act on the bone structure, setting it in motion.
Muscle fibers contain a special substance called sarcoplasm, which contains mitochondria. These elements make up about 30 percent of the total muscle mass and metabolic reactions take place in them. Also, myofibrils are immersed in the sarcoplasm, the length of which is equal to the length of the muscle fibers.
Thanks to myofibrils, muscles have the ability to contract and they are composed of sarcomeres. When a signal arrives from the brain, sarcomeres contract due to the presence of two protein structures: actin and myosin. Under the influence of the load, the cross section of all muscle elements increases. Muscle growth is due to an increase in fiber diameter. And not their quantity, as many athletes believe. The number of fibers is determined genetically and does not have the ability to change.
Skeletal muscle fiber types
Each muscle contains fast and slow fibers (BV and MV). MB fibers contain a large amount of myoglobin. This substance is red and for this reason slow fibers are often referred to as red. The main feature of MB fibers is their high endurance.
In turn, BV fibers contain little myoglobin and are usually called white. Fast fibers are capable of developing great strength and in this indicator they are ten times superior to slow ones.
If the athlete uses less than 25 percent of the maximum load, then mostly slow fibers are included in the work. After the supply of energy resources of the MB fibers has been used up, fast fibers are connected to work. When performing an explosive movement, slow and fast fibers enter into work in the same order, but the delay between the onset of their activity is extremely small and amounts to several milliseconds.
They are almost simultaneously connected to the work, but the fast ones are able to reach their maximum power much faster. For this reason, we can say that the explosive movement is mainly due to the white fibers.
Energy supply of muscles
All work requires energy and muscles are no exception to this rule. The main sources of energy for muscle fibers are carbohydrates, creatine phosphate and fats. If necessary, protein compounds are added to this list, but this happens only in the most extreme cases, for example, during hunger.
Muscles have the ability to store phosphate compounds (creatine phosphate), glycogen (synthesized from carbohydrates) and fats. The more training experience an athlete has, the more energy resources his muscles have.
The main source of muscle function is ATP. During the reaction of its splitting, ADP (adenosine diphosphate), phosphate are formed, and also energy is released, which is spent on performing work. It should also be noted that most of this energy is converted into heat, and about 30 percent is spent on mechanical work. ATP reserves are very limited and the body, to restore the energy supply at a certain moment, triggers a reverse reaction. When ADP and phosphate molecules combine, ATP is formed again.
Glycogen is also used when muscles work. During this reaction, a large amount of lactate is released, which enters the muscles. To avoid this, it is necessary to stop the exercise in time. Note that with the use of interval loads, the release of lactate occurs more intensively than with a single intense load.
You can visually familiarize yourself with the technique of performing strength exercises in the gym in this video: