Exclusive Tips from Dr. Norbert L. Becker
Sensorimotor Function
We have already learned a great deal about the foot, dear readers of my blog! You have read about how the foot developed, how it changes over the course of life, what gives it internal support, what makes it tense, and what makes it elastic and mobile.
But how is it that humans can stand on their feet without falling over? How can they walk without straying from the ‘path’? How is it possible to stand on one leg, jump, and hop? How can our heroes play football without twisting an ankle or missing their step—at least most of the time?
Like our entire body, our feet are equipped with a large number of sensors. These provide us with important information. They tell us whether our feet are warm or cold and what pressure is being exerted on which part of the foot. The sole of the foot is covered with sensitive elements almost as densely as our hand. And we are all aware of how extremely sensitive our hands are. Millions of sensors in the feet transmit their information via nerve pathways to the central nervous system and therefore also to the brain: This is how we learn how great the pressure on the sole of the foot is, what the surface we are standing on is like in terms of its structure and temperature, and whether the ground is stable or perhaps vibrating or swaying like a rowing boat when boarding. The position of the foot and ankle joints is also reported to the central control system.
Through its sensory system, the foot also gives us an impression of the footwear we are wearing. Do we primarily perceive support and stability, or rather instability, for example because of a high heel? Do the toes have enough room, and does the shoe provide a sense of well-being, or is the foot constricted and subjected to pressure?
The sensory information is processed in the brain, creating—consciously or unconsciously—a picture of the current loading situation, environmental influences, the position of the body, its movement, and its speed through space. Perceptions from the eyes and the organ of balance also supplement the peripheral information to form a complete picture in the brain.
The brain coordinates this wide range of information in a fraction of a second, compares it with stored information and movement patterns that we have learned throughout our lives, and then sends commands via the nervous system to the muscles to control the body and coordinate the elements of the musculoskeletal system. In other words, signals are sent from the central control system to the periphery, allowing our feet to learn which movements are to be performed.
What does this mean in practice? If, for example, the foot steps on a sharp object, the sole of the foot reports the unpleasant or even painful sensation to the brain via the nervous system, where this information is processed. The brain accesses stored information and creates a movement pattern in a fraction of a second as a response to avoid the pain or even injury. Reflex-like movements are either carried out unconsciously, or muscles are consciously activated to relieve the affected leg or foot. The pressure on the foot decreases, and the pain signals become less intense.
Without sensorimotor function, we could neither stand nor walk. It enables people to move safely and protects the body from injury. Sensorimotor function is used particularly impressively in football, for example. The foot’s sensitivity and sensory system tell the player how firmly and securely the supporting leg is planted on the grass and with what force and spin the kicking foot can execute the shot.
Our sensorimotor system can be maintained, trained, and activated even if we do not play in the football Bundesliga. Foot exercises and gripping exercises, yoga for the feet, and frequent barefoot walking on different surfaces can all produce training effects that support good sensorimotor function.
However, we rarely walk around barefoot; instead, in everyday life, we protect our feet with socks and shoes. This raises the question of how we can best preserve and support the functionality of our sensorimotor system.
If shoes are too tight, particularly in the forefoot area, or if they are too soft, too hard, or have heels that are too high, they alter the biomechanical loading processes involved in walking and standing. Sensory information is altered or transmitted incompletely. As we age, the sensitivity of the sole of the foot declines, meaning that in older people, information about the condition of the ground and the body’s current position in space can no longer be detected and processed by the brain as precisely, rapidly, and comprehensively. For this reason, especially in later life, it is important to provide the foot with a shoe that protects it, gives it room, and also supports it, limits the effects of the loss of sensitivity, and promotes the sensitivity that remains.
