• A.Shapiro, PhD

What Does the Human Gait Hide? From Aristotle to the Present Day [Part 1]

As it is known - "sound mind in sound body". True, in Ancient Greece and Rome, at the time of the philosopher Thales and the poet Juvenal (who are credited with these words), it was only about the fact that a healthy mind in a healthy body is a rather rare phenomenon, implying the special grace of the gods. And the whole expression looked something like this: «Mens sana in соrроrе sano – avis rаrа» - A healthy mind in a healthy body is a rare success. If Juvenal saw what was done with his legacy in our time, then probably he would have issued something like:

A healthy body is said to mean a healthy mind,

But these two side by side are so hard to find…

But Juvenal stayed in his time. And already closer to us, other enlighteners and philosophers J. Locke and J. J. Russo, for example, also spoke about this. It was thanks to them that this aphorism came down to us in its current modified interpretation. And this modern interpretation focuses on the mutually complementary development of soul and body, that is, the harmony that every person should strive for, even if in fact it is rarely achievable. The difference between physical and mental health is great, but their connection is inextricable. In the past the "Dialogue between the soul and the body" attracted philosophers and poets, then in our time this area involves a great many scientists (including physicians), who every day have more and more previously inaccessible means to invade such subtle spheres.

One of the powerful methods for analyzing human health, both physical and mental, is the study of his gait. Harmony in a person, his physical and mental health begins with his gait, and can be assessed based on its analysis.

The beginning of the scientific analysis of gait is considered to be the work of Aristotle: "De Motu Animalium" - On the Motion of Animals, that sets out the general principles of animal locomotion. The next significant work in this direction was written much later (published in 1680), but had the same name. Its author was an outstanding scientist of the Renaissance and the father of biomechanics - Giovanni Alfonso Borelli, Italian physiologist, physicist, and mathematician. He lived during the time of the Titans: Galileo, Descartes, Newton, etc., and was considered one of them. His innovation was, in particular, the fact that he applied in biology 'rigorous science' - analytical methods developed by Galileo in the field of mechanics. His methods and area of application have inspired a huge number of future scientists and inventors.

Human walking is one of the most important topics in biomechanics. We perceive walking as something routine, simple and ordinary. But in fact, this is a very complicated process. A complex coordinated activity of muscles and limbs is carried out in the human body to take a simple step forward. This process uses about 200 muscles (there are about 650 muscles in the body). Biomechanically speaking, "gait is the pattern of movement of the limbs of animals, including humans, during locomotion over a solid substrate".

But walking isn't just about anatomy, muscle and limb mechanics and coordination. In the peculiarities of walking, information about the human character, the state of his mind/psyche can be encoded. One of the first treatises devoted to the psychology of human gait, 'The Theory of Walking' (1833), belongs to O. Balzac. This work laid the foundations of a humanitarian approach to the expression study.

Another publication tells about an interesting study that has already been done in our time. It turns out that attackers often choose their victims as a result of analyzing the gait of a stranger (maybe even without completely realizing it). In particular, this study used the Laban Movement Analysis - a method and language for describing, visualizing, interpreting and documenting all varieties of human movement. Such formalization is used, for example, by professional dancers. Using this analysis, they were invited to explain the following phenomenon: there is a certain correlation in the choice by prisoners (who were shown prepared clips) the same candidates for attack, even among those you’d expect to be least easy to assault. As a result, it became clear how exactly our gait can increase / decrease the risk of getting into trouble. Prisoners gave preference to potential victims with a bit less coordination - "the critical variable in criminals' predatory decisions". As such studies have shown, the information that we read by observing a person's movement is often more critical than, for example, his face and facial expressions. To illustrate this somewhat unexpected statement, we strongly recommend that you use a technique known as point light walker. [In case you don't know what it is - follow this link, please, and play with the parameters (Gender/Weight/Nervousness/etc...) of the walking person model, without a face. You will not regret it!

Written by: A.Shapiro, PhD, Algorithm Specialist