balance is a very complex thing. Dwelling on a definition in physical terms, the meaning of balance is the following: “condition of a body which, in a physical system, remains immobile because it is stimulated by equal and opposite forces”. This definition also applies to the human body: we manage to stay in balance because muscle tension balances the force of gravity in such a way as to allow us not to move. But what is it that controls muscle tension in relation to gravity? Consciously we are not able to graduate the muscles that contract in order to maintain balance, we can only try to balance the weight without being fully master of this mechanism. Balance takes place mostly on an unconscious level. The main mechanisms that regulate it are:
Vestibular system
The vestibular system is a complex apparatus found in the inner ear, precisely in the petrous roca of the temporal bone. This apparatus is composed of 3 semicircular canals filled with liquid (endolymph) and oriented in the three spatial planes or sagittal, frontal and transverse planes. These three channels refer respectively to three ampules. In each ampoule there are otoliths, small cilia connected to sensors capable of detecting movements of the first ones. On the otoliths there are grains of calcium carbonate, these molecules are able to alter the rheology of the endolymph making it denser. When the head moves in space there is a displacement of the liquid in the semicircular canal corresponding to the plane of movement, this flow of endolymph generates displacements of the otoliths which therefore detect this information and transmit it to the vestibular nucleus. The nerve fibers that start from the vestibular apparatus and arrive at the vestibular nucleus (at the border between the medulla oblongata and the pons) are grouped in the vestibular nerve, the eighth cranial nerve. These impulses are processed by different components of the CNS and the result is that at a subconscious level we know how our head is oriented in space. Based on this orientation, there are nerve pathways that modulate the tension of certain postural muscles in order not to fall. The vestibular system is also able to detect if the body moves with a straight and uniform acceleration or if it is subject to angular acceleration. There is another system that uses the tension of the neck muscles, it could in fact occur that the head remains straight but the rest of the body moves. In this case, muscle tension is recorded, it is processed and integrated with a contraction response of specific muscles to maintain balance. If these two systems, vestibular and neck muscles, are activated at the same time, then the stimulus is canceled, preventing a contraction of the postural muscles when it is not necessary. all of this happens outside of our awareness.
Visual system
The visual system is connected with the vestibular nucleus. The orientation of the eyes with the horizon is in fact integrated with the system that regulates the balance and vice versa the vestibular apparatus is integrated with the visual system. This allows us to keep our gaze fixed on one point while we are in motion. The fact that the balance is also regulated by the gaze means that while we move, and therefore the gaze moves, we are able to have an additional sensory feedback of our movement and therefore the tension of certain muscles alters in response to the type of movement.
Muscle tension
The nervous system is also able to detect the variation in tension of the postural muscles and send it to the nervous system which, integrating everything with the previous systems described, elaborates a response that modulates muscle tension. For example, if an elongation is recorded in the posterior muscles of the leg (the main gastrocnemius and soleus) these send a signal to the CNS which has a further confirmation of the movement of the body in space. There are particular spinal reflexes, for example by stimulating the Achilles tendon, which induce a sensation of variation of balance. All these systems connect to the nuclei of neurons in the CNS that interact with other nuclei forming an elaborate network capable of processing precise and practically immediate responses. The CNS works economically: it is able to memorize the situations encountered and therefore manages to anticipate the response.
Balance and training
By understanding how the body works we are also able to exploit these systems rather than trial and error. This discourse not only applies to balancing exercises but also to exercises such as squats and deadlifts. The condition of precarious equilibrium is in fact registered as a danger and in the face of danger the nervous system places barriers limiting the potential of the muscular system. In fact, it would not be ideal to endanger the health of the organism and our nervous system acts based on self-preservation. A dangerous situation corresponds to major efforts when stability is precarious. The high weight of a barbell represents a dangerous condition just as a precarious balance is interpreted as a risk. The nervous system therefore applies barriers that prevent risks. Referring to what has been said previously, we know that balance also refers to the visual parameter: if the gaze moves then a shift is perceived. This means that moving the view while performing exercises, for example a squat, is counterproductive. On the other hand, keeping the gaze fixed on one point is useful for perceiving greater balance and therefore preventing the nervous system from establishing unwanted limits on the strength expressed by the muscles.
Another balance parameter is the tension of the postural muscles, in particular those that directly discharge the force generated, if you are standing then the muscles of the leg and foot while if the weight is in the hands the muscles of the distal upper limb and appendicular. If these register a movement, the nervous system automatically goes into a state of danger and inhibits muscle activity. This means that to maximize the force output it is necessary to have stable contact with the bearing surface of the weight. All these tricks find an immediate practical response: try to perform free body squats and at the same time move your gaze from one side to the other. Or do bodyweight squats on a slippery surface.
Balance and experience
Fortunately, the nervous system is able to exploit the accumulated experience to cope with an effective response. “Fortunately” because otherwise we would not be able to run at full speed as this situation would be perceived as sudden and therefore we would be limited in our capabilities. This concept applies very well to calisthenic style training: if we were unable to experience the balance response we would never be able to maintain a hand stand position. The equilibrium response is not the only parameter that influences these activities but it certainly plays an important role. Since experience plays a fundamental role in learning balance, it is good to practice movements that require a high level of balance on a daily basis. It is possible to do this without heavily taxing muscles and CNS as until you have full mastery of balance the muscle recruitment is not maximum and therefore the exercise is not too heavy.
Conclusions
Balance is a very complex thing that belongs to the non-conscious component of the nervous system. This means that it regulates voluntary processes. To make the most of this complex system, it is useful to take precautions while performing important exercises. These gimmicks are:
- Keep your gaze fixed on one point during the entire duration of the exercise. The point where you look must be specially chosen in order to regulate the orientation of the gaze and the curve of the cervical spine. These two parameters will in fact affect the rest of the alignment of the body.
- Maintain tension throughout the body. this allows not to waste energy and also prevents unwanted movements of the center of gravity which inevitably alter the tension of the muscles that maintain balance. This condition of solidity is perceived as a security and allows you to better express your muscular abilities.
- Experience plays a vital role in learning balance. While performing important exercises it is useful to concentrate on the position of the body and look for particular reference points that are beneficial in the execution of the exercise (for example weight on the center of the foot or on the central part of the hand).
- Learning is also expressed through practice: a lot of practice is required to learn the best exercises in which balance is the limiting factor.
Baduini Alberto
