Muscles of the chest and abdomen
The main muscles of the chest are the pectoral muscles, which raise the arms during contraction, and the intercostal muscles, which raise the ribs during inhalation. Between the chest cavity and the abdominal cavity, inside the body, there is a muscle similar to an open umbrella - the diaphragm, which contracts when we inhale air to raise the ribs and increase the volume of the chest. The obliques do the opposite job of the diaphragm: when they contract, they pull the ribs down and expel air from the lungs. When the rectus abdominis muscle contracts, it allows you to bend at the lower back.
Muscle pain occurs when an untrained muscle is subjected to intense physical activity, resulting in the formation of lactic acid. The best way to prevent these pains is to exercise regularly. To prevent cramps caused by sudden contraction of a muscle group, it is necessary to do a good warm-up before any sports activity.
When talking about joint damage, words are usually used incorrectly. A sprain is damage or rupture of the ligaments, but the bones of the joint remain connected, while a dislocation is the displacement of a bone from the place it usually occupies in the joint.
The fastest muscle in our body is the muscle that opens and closes the eyelids, which can contract up to five times per second.
The amount of muscle in the human body is so impressive that it can range from 30 to 50% of the total body weight.
The masseter muscle, which moves the jaw when chewing, is one of the most developed muscles - its force is equal to 100 kg.