Many animals can stand on two legs. But no mammal has dedicated itself to this practice full time, like humans. You only need to observe a skater's pirouettes to be convinced that, more than a practice, standing is an art. Walking upright is as deeply human as writing, ethics, and the search for meaning are. And possibly, without the first, there would be seconds.
In our prehistory, our most distant ancestor was naturally selected toward verticality over tens of thousands of years. Verticality offered pre-humans survival advantages. In the natural world, we see countless examples of how uprighting the body off the ground can be beneficial. Having our eyes higher off the ground gave us more information about our immediate surroundings and the dangers that lurked (meerkats know this, and they stand guard over their burrows). Walking on two legs facilitated the execution of another patently human activity that was very necessary in the early days: running. Damn, you had to run to avoid being some smilodon's dinner! (even today some lizards only stand up to sprint in terror).
All in all, walking on two legs is not in itself the formula for the genetic success of a species. If so, we would be in a constant war of world domination with the pigeons. And during the process of exploring the bipedalism of pre-humans something unexpected happened: the liberation of the hands. Not being essential for locomotion, pre-humans began to touch things, to interact with the world that welcomed them. The once foreleg developed an opposable thumb and the brain was forced to gain weight to make sense of all the new information acquired through the fingers. From there, like a dizzying waterfall, curiosity, mastery of fire, writing, creativity and the ability to solve problems with ingenuity followed one another. This turning point - ingenuity - is perhaps the backbone of modern humans.
Since then, in a very short period of time (on a biological scale), as if it were the big bang itself, the development of complex societies, the construction of cellos, satellites and mobile phones; and the contemporary era as we know it. And all this happened with all of us perfectly supported only on two legs. Since we can plant our feet and raise our hands, every Eureka of humanity has been shouted with our gaze in the clouds. It is difficult to define how much this top-down conception of things defines us. We see touches of verticality in our conception of religions, in monumental architecture, in Instagram videos, among others.
Something that naturally goes unnoticed by most are the physiological mechanisms that sparked this evolutionary explosion. Standing up as we did implied a very radical morphological change in the spine. This was a biomechanical challenge unprecedented in the natural world. Never before has there been a species that abandoned quadrupedity with such resolution.
The evolutionary process that brought us here implied that our spine deviated from the common straight line. Most mammals have a spine with a unique gentle curve; but ours became sinuous, full of curves: crazy. But we humans, who write history, call these adaptive deformities “physiological curves.” Unlike the great apes, we now have more mobile lumbar vertebrae and flexibility that gorillas and orangutans would kill for. The sacrum and pelvis, seats of the spine, also experienced important modifications. The human pelvis became narrower and more tilted than others, and made it easier to balance our body.
The motor control of the new vertical scheme required a dynamic mechanism of ligaments, muscles and tendons that had not previously existed. Thus, while studying this process, George Louis Lecler Buffon asserted in 1755 in the fifth volume of his Natural History: “only humans have buttocks.” In an unexpected twist, the history of our verticality is, therefore, also the history of the glutes. A muscle group (like so many others) that in primate cousins seems unremarkable, but in humans it is a powerful stabilizer of the hip and without which we would have colonized the planet with our noses stuck to our knees.
It is in our fat brain where the participation of each muscle is calibrated to allow us to live in adequate balance around the 33 vertebrae arranged vertically, one above the previous one. The system is so complex that in vivo calibration requires a lot of practice and error. Isn't it striking that it takes humans a year to start walking while the average bambi jumps a few hours after birth?
At the time when this avant-garde vertical column was created, the pre-human maintained a strict energy balance. Walking through the prairie digging for worms and avoiding predators was exhausting. To do this, all those pre-humans had a muscular system conditioned to long marches and very intense physical tasks such as climbing trees and fleeing from dangers. The daily caloric expenditure must have been tremendous and food was scarce. Every kilojoule of energy saved translated into better chances of survival.
Pre-humans lived intensely for about 30 years and few had the luxury of aging. The backbone of yesteryear must have been designed with this precept in mind: metabolic efficiency. Living meant a very fine energy balance where one ate and spent what was just and necessary. Body fat percentage was probably extremely stable among our ancestors, as it is now with wild animals. Have you ever seen a zebra fatter than the others? It is indisputable that our verticality occurred due to the tremendous physical activity we carried out.
That is why currently, our column is evolutionarily decontextualized. Humans no longer need to flee from dangers. Humans now live double or triple as long as pre-humans. Now humans carry responsibilities, not stones or logs. Humans no longer cross the earth, but the web; Humans now systematically pass the 80-year-old barrier. Calorie sources no longer escape from our lances, but are delivered to homes by motorcycles. As if that were not enough, very few humans maintain levels of muscular activity comparable to the paleo-crossfit that was life in the Pleistocene.
Even so, as a product of our evolutionary history and a commemorative monument of our unique progress as a species, we all have there behind us, between our shoulders, a powerful biological machinery prepared to daily perform physical feats that are now Olympic, once subsistence. Unfortunately, most of our columns live in the torpor of inactive contemporary life.
The modern lack of physical activity and loss of energy balance explains why more than 80% of humans suffer from back pain today. The statistics of recent decades are clear: axial pain is a growing problem. There is an increase in the consumption of economic and social resources to alleviate this health problem of global impact, which especially afflicts the richest and most sedentary countries. Think about it like this: our columns that were designed for 30 years of activity, but today are subjected to the test of 80 years of sedentary lifestyle. And it is surprising to us that they do not endure pain-free; that fail in a test for which they were not designed.
Luckily, our ability to solve problems has long been focused on this situation and there are more therapies, less invasive techniques and surgical procedures that help us overcome this disagreement between manufacturer and consumer. We should not, even remotely, fall into the error of believing that the optimal solution for a sedentary and aging population, with back pain problems, lies in the interventional techniques of the future. It would perhaps be more useful to reconnect with the human social practices of our original past. Knowing where we are going has always been easier if we remember where we came from.
The key to spinal anti-aging is to maintain a spectrum of activity as similar as possible to what our body was designed for. Cardiovascular physical activity and strength training are the two pillars to achieve this goal. Doctors will agree that performing moderate intensity physical activity is beneficial for the cardiovascular system, for metabolic problems and of course, for musculoskeletal ailments. Carrying out three 45-minute sessions per week has been the golden rule for many years and the World Health Organization prescribes that guideline. But how much activity is enough for a given individual? What constitutes physical activity as we age?
It is difficult to know which exercises are appropriate for each decade of life. A first step in the right direction would be to be consistent with pre-humans. Beyond an exercise routine, adopting a more active lifestyle is the most organic. Choose walking instead of driving, stairs instead of the elevator, carry the shopping bag, play sports and go dancing, run after the dog, enjoy your limbs in their full range of motion and don't just sit still. in modern chairs (in which none of the joints will pass ninety degrees).
Evolution prepared us for a life different from the one we have: shorter, more explosive and active. We ingenious humans have known how to prolong, calm down and enjoy what was given to us like no other species to date. So much so, that we often forget where we started. Maintaining the original level of activity is almost impossible, but anything close to it promises to age more sweetly.
