Any kind of impact on the physical body at times becomes more productive if a person understands which muscles he uses, how they depend on each other and how to work them out as much as possible to get a quick and high result. In this article, we will consider extensors and flexors muscles, their work and interaction features using simple and accessible to a common understanding examples.
What are the opposite muscles in action?
The human muscles are designed in such a way that many muscles have “brothers” that perform the completely opposite work: at the moment when one muscle is tensed, the opposing muscle relaxes, and vice versa.
These muscles - flexors and extensors that control the movement of the human body or individual limbs in space, are called antagonists. It is in this way that a person makes movements - thanks to the control system strictly coordinated by the brain and the coordinated work of the muscles that move the skeleton.
How do they work?
The brain gives an impulse to the nerve endings of the muscle, such as the biceps of the arm, and it contracts, flexing the arm. Triceps - extensor of the arm - is relaxed at this moment, as the brain gave the corresponding signal to him.
Muscles flexors and extensors, that is, antagonists, always work in concert, mutually replacing each other, but sometimes they can work simultaneously, maintaining a stationary, that is, a static position of the body in space. A striking example of such work is the well-known pose of the bar, in which the body hangs motionless above the floor, resting only on the hands and toes. Most of the main flexors and extensors of muscles in this pose perform exactly half of the work necessary for them, as a result, the body withstands this position. If a person does not strain, say, the abdominal muscle, then his back becomes hard, because under the pressure of gravity the lower back begins to bend and sag. Arms lowered along the body downward are antagonists of fully relaxed muscles, and an outstretched arm in front of you at shoulder level is the synchronous work of both muscle groups.
What determines the quality of movement?
The quality of the muscles of the flexors and extensors depends on several factors:
- The amplitude of the movement mainly depends on the length of the muscle fibers and the factors that inhibit them, for example, muscle spasm or post-traumatic scar greatly reduce the range of motion, and elasticity and good blood flow, on the contrary, significantly add amplitude to the work of the muscle. That is why it is important before a workout to warm up the body well with dynamic movements in order to saturate the muscles with blood.
- The strength of a muscle depends on two aspects: the magnitude of the lever that the muscle uses, and directly the amount and thickness of the muscle fibers that make up it. For example, lifting a weight of 10 kg using the entire length of the arm is easy (large lever), and lifting it only with a brush will be more difficult. The same is with the number of muscle fibers: a muscle that is 5 cm across is several times stronger than the one that has a thickness of only 2 cm.
- All muscle movements are controlled by the somatic nervous system, so all body movements, especially the coordinated actions of the muscles of the flexors and extensors, depend on the speed and quality of its work.
If an athlete knows about the proper functioning of the muscles, his training becomes more conscious, and therefore correct, the level of efficiency increases significantly with less energy.
Examples of muscle antagonists
The simplest examples of flexor and extensor muscles are:
- Hip biceps and quadriceps are the flexors and extensors of the legs, more precisely the hips. The biceps is located behind, attached to the sciatic bone above and below, passing into the tendon, adjacent to the femur in the area of the knee joint. And the quadriceps is an extensor, located on the front of the thigh, is attached by a tendon to the knee joint, and the upper part is attached to the pelvic bone.
- Arm biceps and triceps are the flexors and extensors of the arm located between the elbow and shoulder joint and attached to them by powerful tendons. They are the main muscles that form the shoulder, control the vast majority of arm movements for flexion and extension.
You can often notice that if an extensor is too active, then, as a result, the flexor muscle will be in a passive state, that is, it will not be worked out enough, which creates inadequate body movements with a greater loss of energy than harmonically trained people (yogis are an example) .
Another example of muscle antagonists
The rectus abdominis muscle and the longitudinal along the spine, along with the lumbar muscle, are also bright representatives of the flexors and extensors of the body, and they are the most global, because thanks to their coordinated and uninterrupted operation, the human body takes various positions in space: from the vertical torso to the bending into an arc or, on the contrary, deflection back.
And if a person works to correct his posture: eliminate kyphosis, correct scoliotic curvature or remove hyperlordosis in the lower back, he needs to not only work out the extensors of the spine and lumbar muscles, but also actively pump the press muscles, in particular the longitudinal muscle of the abdomen.
Pectoral muscles and rhomboid backs
These two pairs also belong to antagonists, although they are often undeservedly assigned to other categories. The relationship of spasm of the pectoral muscles and passive rhomboid muscles of the back has repeatedly become the field of study of physiotherapists and yoga therapists, kinesiologists and rehabilitologists. The pectoralis major and minor muscles resemble a fan in shape. They are located on the front of the chest, originate in one bundle of the clavicle, the lower - at the upper abdominal wall and are attached to the crests of the humerus. Spasm of the pectoral muscles can be determined not only by the stoop of a person, but also by the position of his arms, lowered along the body. His hands from the shoulder and down to the hand will be turned inward, that is, the hands will look back with their palms.
The rhomboid muscles are located between the shoulder blades, controlling their work together with the trapezium, which, in turn, are directly dependent on the freedom of the shoulder muscles, in the area of which there is already a fastening of the pectoral muscles. As a result, the person works on the stoop, loading the back muscles, but in reality he needs to get rid of the pectoral muscle hypertonus first, then work out the muscles of the extensors and flexors of the neck, which will give freedom to his posture.