This chapter will present an analysis regarding the posture and gaits of the human body; On the one hand, there is the study of human gait, which is an “important diagnostic tool in the evaluation of neuro-musculoskeletal pathologies, whether they are transitory or permanent, local or general,” while on the other hand, there is the posture study, “is intended to provide a comprehensive vision of diagnosis and treatment guidelines of the systems that influence posture.”

Taking into account the above, the analysis will begin with the aspects related to the posture, to then expose the aspects related to the gait, both being the indicators that can be observed in the patient when the medical expert wishes to evaluate the gait, the balance , as well as, the posture, size of the steps, among other relevant characteristics to determine any pathology.

1. Structuring of the human posture according to the theory of evolution of the species.

Due to the research and very definite opinion of Charles Darwin – who was a British naturalist proposing in his time the theory of biological evolution by natural selection – the debate began on the evolution of man, and of all species in general, and it is that Darwin considered that “species change over time, give rise to new species and share a common ancestor”.

The book entitled “On The Origin of Species” published by Darwin, gave way to the theory of evolution of species, which genre and continues to generate controversy due to the scope and limits that this theory has. Now, far from all the controversy that the book or the theory has raised, it is valid to highlight one of the evolutionary characteristics of the human being, which is related to the human posture.

Walking represented the most effective way of moving on the ground, which is why I demand various evolutionary changes at the anatomical level, including: the lengthening of the lower extremities, the shortening and widening of the pelvis, the adjustment of the muscles of the hip, foot changes, forward curvatures in the lumbar region of the 

spine, among others ”; being such anatomical modifications, and characteristics of the human being.

Then it can be considered that the posture made man, since as the greatest embryologist of the 19th century, Karl Ernst von Baer put it, “The upright posture is only the consequence of the highest development of the brain (…) all the difference between the man and other animals depend on the construction of the brain ”; while for his part, the English anthropologist G. E. Smith stated that:

It was not the adoption of the upright posture or the invention of articulate language that separated man from the ape, but the gradual refinement of the brain and the slow construction of mental structure, of which upright posture and language are some of its incidental manifestations.

2. Anatomical planes and body axes

The human being has a basic anatomical position, this is the position acquired by the person placing their feet slightly apart, keeping the Human being has a basic anatomical position, this is the position acquired by the person placing their feet slightly apart, keeping the head upright according to the Frankfurt plane, in addition, the arms are kept extended on both sides of the body, holding the palms of the hands towards the front and the thumbs pointing outwards, all with a slight distance from the torso.

3. Posture of the human body

Body posture “is intrinsic to human beings, since it accompanies them 24 hours a day and throughout their lives.” Posture is also seen as “the composition of the positions of all the joints of the human body at all times.” Within this section the following aspects can be analyzed:

• General biomechanics static – dynamic:

Biomechanics is defined as the interdisciplinary knowledge that is generated by using the knowledge of mechanics and various technologies to study the behavior of biological systems, particularly the human body, as well as to solve the problems caused by the different conditions to which the human body can be subjected.

Regarding static biomechanics, it is one that is carried out when the body is at rest, and in total balance, without any cause that can cause movements to the body.

Whereas dynamic biomechanics is the opposite since it is “subdivided into kinematic areas, which consists of the study of the characteristics of movement, and kinetics, which studies the causes that produce said movement”.

• Dubousset Cone of Economy :

Dubousset was the one who developed the concept of the “cone of balance”, with this criterion he intends to warn that balance should not only consider the angles of cervical lordosis, thoracic kyphosis and lumbar lordosis (30º, 40º and 50º average in adults respectively).

But also, the position of the pelvis must be taken into account, which is the true pelvic vertebra according to Dubousset.

In such a way, that through this technique it is possible to analyze if the body can maintain a balanced posture that does not require external support; That is why when the trunk extends beyond this cone (as seen in figure 9) an external support is necessary so that the person can maintain balance; being valid to mention the cases related to balance problems, such as vertigo, being the cone an object of analysis for its diagnosis.

• Body mass distribution: 

The Body Mass Index (hereinafter BMI), is what allows classifying the weight status of the person, and is calculated with the following formula: weight (kg) / height (m2). The World Health Organization (hereinafter WHO) considers some figures that should apply to adults to consider cases of overweight and obesity as follows:

Chart 1 BMI according to WHO (Overweight and obesity)

Overweight — BMI equal to or greater than 25.

Obesity — BMI equal to or greater than 30. 

BMI provides the most useful measure of overweight and obesity in the population, since it is the same for both sexes and for adults of all ages. However, it must be considered as an approximate value because it may not correspond to the same level of thickness in different people.

Now, overweight and obesity significantly influence the alteration of human body movement, which is manifested by alterations in biomechanics; thus, q “the increase in body mass can affect the performance of functional tasks such as balance and promote the risk of falls and injuries”.

• Normal running: Characteristics and phases.

The human body carries out a process of locomotion in a generally upright position, moving forward, while its weight is alternatively supported by its lower limbs, this action is known as normal gait.

Normal gait is characterized “by the individual’s permanent contact with the ground through at least one of his feet”, which distinguishes it from running. It is valid to highlight that although walking is an individual and particular action of each person, there are similarities between one person and another, so it can be considered that there is a characteristic pattern of normal human walking.

When the person is in the stance phase, a subdivision is made “into intervals with the terms of acceptance of weight, medium stance and lift off.” The interval of acceptance of the weight begins with the contact of the heel and ends with the plantar support ”.

While the mid stance interval “begins with plantar stance and ends with heel lift to heel lift off”. And the last interval includes the heel lift and the toe lift ”.

Otherwise, when the person is in the swing phase, the intervals are divided into: acceleration, medium swing and deceleration.

The acceleration interval is related to the speed taken by the lower extremities, while in the intermediate swing interval, the balanced leg passes to the other leg, generating the support phase; and finally, in the deceleration interval, the leg that moves rapidly as it approaches the end of the interval begins to slow down.

• Pelvic Obliquity: Classification and Biomechanical Analysis.

Pelvic obliquity or hip abduction contracture, “is an entity that is detected under one year of age, it is not usual to see in a general Rehabilitation consultation and for which there is little literature”, so it is also a little-known pathology among pediatricians; for these cases, when indicated, treatment should be early. Now, the classification of pelvic obliquity responds to:

• Congenital pelvic obliquity (CPO) is a common type of pathology in infants, and is a sequela due to abduction or adduction contracture secondary to a poor intrauterine position.

In turn, they can be of simple forms, which are those in which clinical or radiological anomalies are not observed in the adducted hip; and of forms with abnormalities in the adduct hip, which present instability (dysplasia, subluxation, dislocation).

Regarding the biomechanical analysis, it is valid to consider that any alteration in the pelvis, sacrum or coccyx manifests itself in the lumbar region, which could indicate that the imbalance or pain in the lumbar region may only be the reflection of an alteration structural pelvic, sacroiliac, coccygeal, pelvic floor, muscular or ligament. In the case of OPC, a contracture of the muscles in the abductor muscles is generated, and therefore, an instability is caused in the lumbar spine, triggering a spino-pelvic imbalance.

• Gait disturbances secondary to a discrepancy in the length of the lower limbs, pelvic obliquity.

As previously stated, gait is the coordinated action of various muscular systems, this means that due to the bipedal condition of the human being, gait includes the interaction of the pelvic girdle and the lower limbs, and to a lesser extent , of the shoulder girdle, the trunk and the superiors to achieve the perfection of the movement. The gaits affected by some pathology of the lower limbs are called: paraparesic gait and cerebellar gait.

Regarding pelvic obliquity, children who have a diagnosis of spastic quadriparesis commonly develop a pelvic obliquity with an apparent discrepancy in the length of the lower limbs; While children who have a diagnosis of hemiplegia, when raising and rotating the pelvis towards the most affected side, they generate a pelvic obliquity with an apparent discrepancy in the length of the lower limbs.

• Introduction to computer-assisted gait analysis and its indications in patients with spinal pathologies.

It is known that currently the development of robotic platforms applied for rehabilitation is widely investigated and promoted; being able to highlight the advances in exoskeletal systems, being humanoid robots a great fascination in the scientific community and in the general population.

Ahora bien, se puede destacar el sistema robótico Lokomat, siendo implementado para “la rehabilitación del aparato locomotor con el propósito de entrenar o reentrenar la capacidad de marcha mediante la repetición de una tarea específica considerando el concepto de plasticidad neuronal”. 

This system consists of “an orthosis for robotic gait and a modern body weight unloading system, combined with a treadmill”; this dynamic unloading system – which has little inertia – “allows precise unloading of the patient and encourages a more physiological gait for optimized sensory stimulation.”

Spinal pathologies are the main beneficiaries of computer-assisted walking, although there are several high-cost technologies that have been developed to improve the condition of patients with such pathologies, it is also true that despite their good results at the experimental, have not yet become generalized in clinical practice.