Many people are accustomed to perceiving flexibility as a purely mechanical process of Stretching muscle fibers. This is a fundamentally wrong approach. When a person performs a splits, a deep bend or a bridge, a complex cascade of physiological reactions is launched in his body. Many people mistakenly imagine a muscle as an ordinary rubber band: if you pull harder, it lengthens. However, the human body is orders of magnitude more complex. Tissue elongation is not the result of physical Stretching of fibers to the limit of strength, but, first of all, the result of neurological adaptation, structural restructuring of the fascial network and profound changes in hemodynamics.
Muscles do not exist in isolation. They are woven into a single connective tissue matrix, controlled by signals from the central nervous system and depend on the quality of the blood supply. True flexibility is achieved not through overcoming pain, but through competent interaction with the physiology of the body. In order for training to bring health and stable results, you need to understand what exactly happens under the skin during each exercise.
60% discount on all video workouts
Fascia: the hidden framework of our flexibility
For a long time, anatomists considered fascia only as packaging material for muscles and internal organs, without attaching much importance to it. Today, biomechanics recognizes the fascial network as the main organ of shape and transmission of mechanical stress. Fascia is a continuous three-dimensional web of collagen and elastin that runs throughout the body from the top of the head to the feet.
What is fascia and body architecture
Each muscle fiber is wrapped by endomysium, bundles of fibers by perimysium, and the entire muscle by epimysium. These layers of connective tissue fuse at the ends of the muscle to form a tendon that attaches to the periosteum. When we try to stretch the hamstrings, we are not only Stretching the biceps femoris, semitendinosus, and semimembranosus muscles. We target the entire posterior superficial fascial line, which runs from the plantar fascia through the calves, hamstrings, sacrum, back extensors, to the occipital bone and brow ridge.
The degree of elasticity of the body directly depends on the condition of collagen fibers. If tissues do not receive enough movement or are exposed to chronic stress (for example, during prolonged sedentary work), fibroblasts begin to synthesize excess collagen, forming so-called adhesions or cross-links - chaotic cross-links between fascial layers. These adhesions limit range of motion and create a feeling of rigidity. Moreover, fascia has a piezoelectric effect. Mechanical tension creates a weak electrical charge in collagen fibers, which is captured by fibroblasts. Depending on the vector and duration of tension, fibroblasts begin to rebuild the tissue architecture, dissolving old rigid cross-links and forming new elastic fibers strictly along the lines of force application.
Fascial slip and hyaluronic acid
Healthy biomechanics of movement is ensured not only by the elasticity of the fascia itself, but also by the free sliding of fascial sheets relative to each other. Between the layers of epimysium of adjacent muscles there is loose connective tissue rich in hyaluronic acid. This acid acts as a natural lubricant.
In the absence of regular physical activity, hyaluronic acid thickens and its consistency becomes more viscous. Layers of connective tissue stick together, and instead of smooth gliding, friction and resistance occur. Competent Stretching has a mechanical effect on these structures. Gradual tension and heating of the tissues reduce the viscosity of hyaluronic acid, restoring the “fluidity” of the interfascial space. Fascia has the property of thixotropy - the ability to liquefy under mechanical stress and increased temperature. That is why smooth, consistent stretches restore the body's lost freedom of movement.
Neuromuscular Connection: A Dialogue Between Brain and Body
The main limiter to our flexibility is not the short muscles, but the central nervous system. The brain perceives any excessive or unusual amplitude as a potential threat to the integrity of the joint and commands muscle contraction to protect itself. Specific proprioceptors are responsible for this protective mechanism.
Muscle spindles: guardians of length
In the thickness of the muscle fibers, muscle spindles are located parallel to them. Their task is to constantly monitor the length of the muscle and the rate of its change. If a muscle is stretched too quickly or sharply (as in ballistic swings or snatches), the muscle spindles instantly send a signal to the spinal cord. In response, a powerful motor impulse is generated, causing the muscle to reflexively contract. This is the myotatic reflex, or stretch reflex. The functioning of muscle spindles is regulated by gamma motor neurons, which constantly adjust their sensitivity. Under chronic stress or high loads, gamma motor neurons increase spindle tone, making them hypersensitive. Trying to stretch through jerks or acute pain, a person literally fights with his own nervous system, provoking micro-tears and spasms.
Golgi receptors: voltage fuses
At the junction of muscle fibers and tendons there are Golgi tendon organs. Unlike muscle spindles, they do not respond to the rate of change in length, but to the level of mechanical tension. When the tension in the tendon reaches a critical point that threatens to be torn from the bone, the Golgi organs send an inhibitory signal to the spinal cord, suppressing the activity of motor neurons. The muscle relaxes. This process is called autogenic inhibition.
How to bypass the defensive reflex
The art of effective Stretching is to “calm” the muscle spindles and activate the Golgi tendon organs. To do this, the tension must be slow, controlled and continuous. When holding a pose statically, the primary resistance of the muscle spindles gradually fades, and the Golgi receptors give the command to relax. The brain receives a safety signal and allows the fascia to lengthen. Breathing plays a key role in this: deep, even exhalations stimulate the parasympathetic nervous system, further reducing muscle tone.
Physiology of Stretching methods: statics, dynamics and PNF
Different techniques affect tissues and the nervous system in different ways. Understanding their physiological basis allows you to build the training process as efficiently and freely as possible.
Dynamic Stretching: Preparation and Warm-Up
Dynamic Stretching consists of controlled movements within a comfortable amplitude without holding the end point. From a physiological point of view, dynamics do not lengthen the fascial tissues structurally, but perform a critical preparation function. It increases the local temperature in muscle tissue, which reduces the viscoelastic resistance of the fascia, stimulates the production of synovial fluid in the joints, improving the gliding of articular surfaces, and also activates blood flow, preparing the cardiovascular and nervous systems for more intense work.
Static Stretching: tissue restructuring
Static posture retention is aimed at changing the viscoelastic properties of connective tissue. When a muscle is stretched and fixed, a phenomenon occurs creep (creep) - slow plastic deformation of tissue under the influence of constant load. Collagen fibers line up parallel to the tension vector, and the fascial matrix is hydrated. This is the fundamental basis for developing deep, passive flexibility.
PNF (proprioceptive neuromuscular facilitation): neurohacking
PNF Stretching uses physiological reflexes to maximize muscle relaxation. Postisometric relaxation (PIR) is one of the most powerful tools in this arsenal. The mechanics of the process look like this: you bring the muscle into a slight tension, then, while inhaling, gently resist for several seconds, creating isometric tension. At this moment, the Golgi tendon organs record an increase in tension. As you exhale, you relax completely. A powerful inhibitory signal from the Golgi organs temporarily turns off the myotatic reflex, and in the next seconds a refractory window appears - a period when the muscle can be safely and deeply stretched to a new amplitude without encountering resistance from the nervous system.
Blood circulation and nutrition of joints: sponge effect
The health of the musculoskeletal system directly depends on the trophism (nutrition) of tissues. Chronic hypertonicity and muscle shortening lead to compression of blood vessels and local ischemia. The tissues are deficient in oxygen and decay products accumulate in them, causing aching pain and stiffness.
Capillarization and oxygen exchange
Proper Stretching acts as a natural vascular pump. When tissue elongates, the capillary network is released from compression. Full arterial inflow and venous outflow are restored. Improving microcirculation promotes the elimination of lactate and metabolic waste, providing muscles with the necessary oxygen and microelements for regeneration. In addition, lymphatic drainage accelerates, swelling is eliminated and the intercellular space is cleansed.
Diffuse nutrition of intervertebral discs and cartilage
Articular cartilage, menisci and intervertebral discs in adults are practically devoid of their own blood supply. Their nutrition is carried out exclusively by diffuse means - due to osmotic exchange with surrounding tissues during movement.
When we perform spinal traction or joint work, there is an alternation of compression and decompression. The tissue behaves like a sponge: when squeezed, waste fluid is pushed out of it, and when stretched, negative pressure is created, which draws in fresh intercellular fluid rich in nutrients. Without regular amplitude movement, cartilage tissue dries out, degenerates and breaks down. High-quality Stretching is a prerequisite for survival for the joints and spine.
Practical conclusions: safe Stretching using a non-contact method
A deep understanding of anatomy and neurophysiology categorically excludes the use of aggressive methods. Forced Stretching through acute pain involving external pressure inevitably provokes the myotatic reflex. The nervous system perceives this as an attack, the muscles spasm even more, and instead of elasticity, tissue tear occurs.
Teaching people flexibility and building training programs using the non-contact method since 2009, I am deeply convinced of one thing: the body never forgives violence. Sustained progress requires respect for physiological barriers. The basic principles of safe practice are based on the following rules:
- Vectoring and pose geometry. It is important to pull the target fascial line while maintaining proper joint angles to isolate the desired structures and not overload the ligamentous apparatus.
- Autonomy of control. You must control the amplitude yourself. The non-contact method ensures that you do not cross the threshold beyond which the Golgi receptors and muscle spindles activate a protective spasm.
- Attention to breathing. Deep, diaphragmatic inhalation and prolonged exhalation during the tension phase reduce the sympathetic activity of the nervous system, sending a clear safety signal to the brain.
- Regularity instead of maximalism. Plastic deformation of collagen fibers and adaptation of the cerebral cortex take time. Daily moderate work rebuilds the architecture of tissues more reliably than rare attempts to do the splits at any cost.
Flexibility is an indicator of the physiological youth of the body, freedom of blood flow and harmonious functioning of the nervous system. By acting thoughtfully and relying on the laws of biomechanics, you not only increase the range of motion, but also return the tissues to their natural functionality, health and lightness.