10 Reasons Why Prehistoric Humans Were Stronger Than Us

Added: 2026-05-19

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[00:00:05]Number 10, in 2015, a paper published in the Proceedings of the National Academy of Sciences compared the bone density and cortical thickness of modern human skeletons against the skeletal remains of prehistoric hunter-gatherers from the same geographic regions. The results were so dramatic that several of the papers reviewers requested the methodology be checked before publication. Modern human bones are, on average, significantly thinner, lighter, and structurally weaker than the bones of our prehistoric ancestors from the same populations.

[00:00:34]The difference is not subtle. The cortical bone, the dense outer layer that provides structural strength to the long bones of the arms and legs, is measurably thinner in modern humans across every population studied. The trabecular bone, the internal lattice structure inside joints and at the ends of long bones, is less dense and less complex in its architecture.

[00:00:52]The overall skeletal mass of a modern human of equivalent height and weight to a prehistoric hunter-gatherer is substantially lower.

[00:00:58]To be precise about what this means in practical terms, the bones of a Neolithic farmer, someone who lived approximately 8,000 years ago and represents one of the later stages of prehistoric human physical development, are closer in density and structure to the bones of a modern chimpanzee than they are to the bones of a modern human being.

[00:01:14]The transition from prehistoric skeletal robustness to modern skeletal fragility is one of the fastest and most dramatic physical changes in the entire evolutionary record of our species. It happened in a geological eye blink. It happened because we stopped loading our skeletons. Bone is not a static structure. It is a living tissue that responds directly and continuously to the mechanical demands placed upon it.

[00:01:34]Every time a load is applied to a bone, whether from carrying weight, from muscle contraction during movement, or from the impact forces of running on hard surfaces, the bone responds by adding density and structural complexity precisely where the load is being applied. Remove the load and the bone removes the structure. This process, called Wolff's Law, operates throughout a person's entire life, but is most powerful during childhood and adolescence when the skeleton is still forming its fundamental architecture.

[00:01:58]Prehistoric children spent their entire developmental years under mechanical loads that modern children never experience.

[00:02:04]They walked on average between 9 and 15 miles per day on uneven ground from the time they could walk at all. They carried water, food, shelter materials, and younger siblings. They climbed, they hung, they squatted for hours, they ran on surfaces that transmitted full impact forces through the foot into the ankle, shin, knee, and hip. Every day of their childhood was a bone-loading exercise that modern sports science would classify as extraordinary.

[00:02:28]The result was a skeleton built to a structural specification that modern humans simply do not develop because the loads required to build it are never applied.

[00:02:35]The truly unsettling implication is what this means for modern bone fragility.

[00:02:39]Osteoporosis, the reduction of bone density that leads to fractures in older adults, was essentially unknown in the prehistoric record. Researchers studying thousands of prehistoric skeletons have found almost no evidence of the spontaneous compression fractures of the spine, the hip fractures, the wrist fractures that are now among the most common serious injuries in elderly modern populations. The prehistoric skeleton did not become fragile with age in the way that the modern skeleton does because it was built to a higher structural standard to begin with.

[00:03:05]We did not evolve weaker bones. We build weaker bones. Every generation that moves less than the previous one produces children whose skeletons are slightly less dense than their parents.

[00:03:14]We have been doing this for approximately 10,000 years, and the cumulative result is a skeleton that the people who built Stonehenge would have found genuinely alarming.

[00:03:21]Their bones were not stronger because they were a different species. They were stronger because they never stopped loading them. We stopped. The bones noticed In 2018, a study published in the Journal of Human Evolution compared the hand bone geometry of modern humans against the hand remains of Neolithic farmers and prehistoric hunter-gatherers from Europe. The researchers were specifically measuring the cross-sectional properties of the metacarpal bones, the long bones of the hand that run between the wrist and the knuckles, because these bones remodel in direct response to the grip forces applied to them over a lifetime.

[00:03:50]The The of prehistoric hunter-gatherers were substantially more robust, more oval in cross-section, and showed a pattern of cortical thickening on specific surfaces that is directly associated with the repeated application of high grip forces.

[00:04:03]The researchers translated these geometric differences into estimated grip strength using established biomechanical models.

[00:04:09]The average prehistoric male hunter-gatherer had an estimated grip strength roughly comparable to that of a modern orangutan. To provide context for what that number means, the grip strength of a modern orangutan is approximately three to seven times greater than the grip strength of an average modern human male.

[00:04:23]It is sufficient to bend steel bars of the diameter used in standard scaffolding. It can crush a hand in a single squeeze with enough force to fracture multiple metacarpals simultaneously. A modern male professional athlete in a grip-intensive sport, a rock climber or a wrestler at the elite level, produces grip forces that are impressive by contemporary standards and would have been considered ordinary, perhaps slightly below average, by the standards of a prehistoric hunting band. The reason is not genetic. The hands of a modern human infant are anatomically identical to the hands of a Neolithic infant. The potential for grip strength development is the same. What differs is the life that follows. Prehistoric hands never stopped working. From early childhood, the hands of a hunter-gatherer were in constant contact with irregular, challenging surfaces. They climbed trees to gather fruit, escape predators, and scout terrain. They processed animal carcasses by hand, stripping hide from flesh and flesh from bone with a combination of tools and direct manual force for hours at a time. They made tools which required sustained forceful manipulation of stone, bone, and wood.

[00:05:21]They carried everything they owned by hand because nothing had wheels. They built shelters, made fire, processed plant food, and fashioned clothing, all entirely by hand every single day without pause for their entire lives.

[00:05:33]The hands responded by becoming instruments of extraordinary mechanical capability. The tendons thickened, the muscles of the forearm increased in both size and the density of their attachment points to the bone. The bones of the hand itself remodeled around the forces is applied to them until the geometry of the hand was optimized for the specific types of grip that the life required.

[00:05:50]Modern hands are used primarily for typing, holding phones, and occasionally opening jars that sometimes require a second attempt. The architecture of the modern hand reflects this. Metacarpals that are round in cross-section where prehistoric metacarpals were oval.

[00:06:02]Cortical bone that is uniformly thin where prehistoric cortical bone was differentially thickened on the surfaces that bore the highest loads. The potential for grip strength is still there in the genetic blueprint. The stimulus to develop it is not. The single most revealing statistic in this area of research is the trajectory.

[00:06:16]Studies measuring grip strength in industrialized populations across successive decades consistently find that grip strength is declining. Young men in the United States in 2016 had measurably lower grip strength than young men of the same age in 1985. The decline is not dramatic within a single generation, but it is consistent and it is continuing. Every generation of modern humans has slightly weaker hands than the previous one.

[00:06:37]The hands of prehistoric humans would not have recognized what we are doing with ours as work. Number eight, they could run in ways that modern elite athletes cannot physically replicate. In 2004, anthropologists Dennis Bramble and Daniel Lieberman published a paper in the journal Nature titled Endurance Running and the Evolution of Homo. The paper argued with a substantial body of anatomical and fossil evidence that the human body is one of the finest long-distance running machines that evolution has ever produced and that endurance running was not an incidental capability of Homo sapiens, but a fundamental driver of our entire physical form. The nuchal ligament at the back of the skull that stabilizes the head during running. The enlarged gluteus maximus that is almost unique among primates. The spring-like Achilles tendon.

[00:07:22]The ability to sweat across the entire body surface to manage heat. All of it is there because our ancestors needed to run and run far and run for a long time in hot conditions after prey that could outpace them over short distances, but could not manage their own body heat well enough to do it forever.

[00:07:38]Prehistoric humans did not run faster than modern elite athletes in short sprints. The evidence does not support that claim. What the evidence does support is something considerably more unsettling. They ran further at pace in conditions that would end a modern marathon within the first hour. In 2016, researchers studying fossilized human footprint trackways at a site in Ileret, Kenya dated to approximately 1.5 million years ago, analyzed the stride lengths and pressure distribution patterns of the individuals who made them. The trackways showed individuals moving at a consistent running pace across terrain that was not flat. One trackway showed a running stride that, extrapolated to a full gait cycle, indicated the individual was covering ground at approximately 11 to 12 mph, not sprinting. Running at a sustained pace with the biomechanical signature of someone who intended to continue at that speed for a considerable time.

[00:08:26]Modern marathon world record pace is approximately 13 mph. The individual at Ileret was not at world record pace.

[00:08:33]They were at the pace of a very good modern club runner. But, they were doing it 1.5 million years ago in the African heat in bare feet on uneven ground while almost certainly having eaten less that morning than a modern runner would consider adequate pre-race nutrition.

[00:08:45]The barefoot element is critical. Modern running biomechanics research, led in part by Harvard's Daniel Lieberman, has demonstrated that humans running barefoot on natural surfaces automatically adopt a forefoot or midfoot strike pattern that distributes impact forces across the foot, ankle, and lower leg in a way that dramatically reduces peak impact at the knee and hip compared to the heel strike pattern encouraged by modern cushioned running shoes. Prehistoric humans who never wore shoes developed foot and lower leg architecture through childhood and adolescence that was specifically adapted to barefoot running on natural surfaces. The intrinsic muscles of the foot, small muscles that stabilize the arch and control the toes, were substantially more developed than in modern humans who spend their lives in supportive footwear. The result was a running machine that could cover enormous distances across difficult terrain without the knee degeneration, the shin splints, the plantar fasciitis, and the hip stress fractures that now sideline modern runners with depressing regularity. The most humbling statistic in this area comes from persistence hunting research. The Kalahari sand people, one of the few remaining hunter-gatherer populations whose hunting practices have been directly observed, occasionally practice persistence hunting, the technique of chasing prey at a steady running pace until the animal overheats and collapses. The distances covered in a successful persistence hunt range from 15 to 35 km across hot uneven terrain.

[00:09:58]The hunters do this in the middle of the day when temperatures exceed 40° C because that is when the thermal advantage over the prey is greatest.

[00:10:04]Modern recreational runners attempting to replicate these hunts in research conditions, wearing modern running shoes, carrying water, with support vehicles following them, have consistently failed to complete the distance without stopping.

[00:10:15]The sand hunters do it without water and without shoes and consider it a normal working day. We were built to do this.

[00:10:21]We just stopped doing doing it and the body forgot. Number sevens, we're fighting battles ours have completely forgotten how to fight. In 2003, a research team led by immunologist Graham Rooke at University College London proposed what he called the old friends hypothesis. Building on the earlier hygiene hypothesis proposed by David Strachan in 1989, Rooke argued that the human immune system did not simply evolve in a clean environment that we have now made dirty. It evolved in an environment of constant microbial and parasitic challenge and that the immune system is not functioning optimally without those challenges present.

[00:10:52]The organisms that challenged it across hundreds of thousands of years of evolution were not random pathogens.

[00:10:57]They were specific organisms, specific parasitic worms, specific soil bacteria, specific commensal microbes that the immune system had learned to tolerate and even depend upon for its correct calibration.

[00:11:07]Rooke called these organisms old friends because they had been present throughout the entire evolutionary history of the immune system and their removal had consequences that looked nothing like the removal of a threat. They looked like the removal of a regulatory mechanism.

[00:11:19]The consequences of their removal are visible in the epidemiological record of the 20th century. Allergic disease, asthma, inflammatory bowel disease, multiple sclerosis, type 1 diabetes, rheumatoid arthritis. All of these conditions in which the immune system attacks either harmless environmental substances or the body's own tissues have increased dramatically in prevalence in industrialized populations across the same period during which sanitation, antibiotics, and antiparasitic treatments have reduced exposure to the old friends. The correlation is not perfect and the causation is complex, but the core of Rook's argument has been supported by enough subsequent research to be taken seriously by mainstream immunology. The prehistoric immune system was not fighting harder than ours. It was fighting smarter. It had the full complement of regulatory organisms that evolution had calibrated it to work with. It knew what to attack and what to leave what to leave leave alone because it had spent hundreds of thousands of years learning the difference in the presence of the specific teachers it needed. The prehistoric gut microbiome was also substantially more diverse than the modern gut microbiome. Studies comparing the gut bacteria of contemporary hunter-gatherer populations whose diet and lifestyle most closely resemble prehistoric patterns with the gut microbiomes of industrialized populations show dramatic differences in diversity.

[00:12:27]The hunter-gatherer microbiome contains hundreds of bacterial species that are absent or present in vanishingly small numbers in the industrialized gut.

[00:12:35]Several of these species produce compounds that directly regulate immune function, inflammation levels, and even neurotransmitter production in the brain.

[00:12:41]The specific implications extend in directions that were not anticipated.

[00:12:44]Research published in the last decade has established robust connections between gut microbiome diversity and mental health outcomes with reduced microbiome diversity associated with higher rates of depression and anxiety in large population studies.

[00:12:57]The prehistoric gut was not just processing food more effectively. It was producing the chemical environment in which the prehistoric brain operated. A brain running on a full complement of microbiome derived neurochemical support was a brain that was at a baseline neurochemical level functioning differently to a modern brain running on a depleted microbiome. The most confronting implication of this research is its trajectory. Microbiome diversity in industrialized populations has been declining with each studied generation.

[00:13:20]C-section birth, which bypasses the microbial transfer that occurs during vaginal delivery, formula feeding, which bypasses the microbiome seeding compounds in breast milk. Antibiotic use in early childhood, which causes significant and sometimes permanent reductions in gut bacterial diversity.

[00:13:35]All of these factors are additive across generations. Each generation in an industrialized population starts with a slightly less diverse microbiome than their parents. The prehistoric immune system was not superhuman. It was correctly calibrated. Ours is running with several of the instruments missing and wondering why the music sounds wrong. Number six, their senses operated at levels we have classified as superhuman because we have forgotten they were normal.

[00:13:57]In 2020, a study published in PLOS One examined the visual acuity of contemporary Amazonian hunter-gatherer populations whose lifestyle, diet, and sensory environment most closely approximate prehistoric patterns. The researchers found that the average visual acuity in these populations significantly exceeded the standard used by optometrists to define normal vision in industrialized populations.

[00:14:18]Several individuals demonstrated visual acuity equivalent to what ophthalmologists classify as eagle vision, the theoretical upper limit of human visual resolution determined by the density of cone cells in the fovea.

[00:14:30]They were not mutants. They were not genetically exceptional within their population.

[00:14:34]They were simply people whose visual systems had developed and continued to function in an environment that demanded and therefore maintained the full resolution capability of the human eye.

[00:14:42]The human eye is capable of resolving detail at a level that most modern humans never experience because the visual environment of modernity does not require it and in many cases actively prevents it. Myopia, short-sightedness, the inability to focus on distant objects was essentially absent from prehistoric populations. Studies of pre-contact indigenous populations across multiple continents found myopia prevalence rates of less than 1% In contemporary East Asian urban populations, myopia prevalence among young adults now exceeds 90% in some cities. The condition has gone from a rare anomaly to a near universal feature of modern human vision within a single century.

[00:15:19]The mechanism is understood.

[00:15:21]The human eye requires exposure to outdoor light during childhood development to regulate the growth of the eyeball correctly. Insufficient outdoor light during the critical developmental window causes the eyeball to grow slightly too long, pushing the focal point in front of the retina and producing myopia.

[00:15:35]Prehistoric children spent essentially all of their time outdoors. The developmental stimulus was never absent.

[00:15:40]The eyes grew to the correct dimensions and maintained the capacity for distance vision that the environment both required and preserved.

[00:15:47]The hearing of prehistoric humans was similarly maintained at a level that modern humans rarely achieve.

[00:15:52]The average hearing threshold of adults in industrialized populations begins declining in the early 20s with frequencies above 8 kHz, the range that carries information critical for locating sound sources in three-dimensional space, typically lost by the mid-30s.

[00:16:06]In pre-contact populations studied in the mid-20th century before industrialization reached their environments, hearing acuity in adults in their 40s and 50s matched the hearing of 20-year-olds in industrialized populations. The prehistoric nose requires separate discussion. The human olfactory system contains approximately 400 functional odor receptor types and is theoretically capable of distinguishing between more than 1 trillion different odor combinations, according to research published in Science in 2014. Modern humans use a small fraction of this capability in daily life because the olfactory environment of modernity, dominated by manufactured scents, indoor air, and the chemical homogenization of the built environment, does not require or develop it. Hunter-gatherer populations studied by anthropologists demonstrate olfactory capabilities that seem extraordinary from a modern standpoint. Tracking animals by scent, identifying individual people by smell at distance, detecting weather changes through atmospheric scent variations hours before the weather changes. These are not superhuman abilities. They are the normal operating capacity of the human olfactory system when that system is used continuously from birth in the environment it evolved to operate in.

[00:17:08]The senses of prehistoric humans were not different from ours in their fundamental design. They were the same system operating at full capacity because full capacity was required every day. Ours are the same system operating at a fraction of that capacity because modernity has made the full capacity unnecessary.

[00:17:22]The eye that can see an eagle at a mile, the ear that can hear a twig break in darkness, the nose that can smell rain 12 hours before it arrives, all of it is still in the blueprint.

[00:17:32]We just never opened the file. Number five, their bodies ran on a fuel system that made modern metabolism look broken.

[00:17:39]In 2000, physiologist Loren Cordain published a detailed analysis of the diets of 229 hunter-gatherer societies whose dietary patterns had been documented by anthropologists before significant contact with industrialized food systems.

[00:17:53]The analysis examined macronutrient ratios, food variety, meal timing, and the relationship between food availability and consumption patterns.

[00:18:00]The findings were not what nutritional orthodoxy of the time expected.

[00:18:04]Hunter-gatherer diets were not consistent. They were not three meals a day. They were not balanced in the sense that modern nutritional guidelines use that term.

[00:18:12]They were highly variable, seasonally driven, and included regular periods of involuntary fasting followed by periods of high caloric surplus when a hunt was successful or a plant food came into season.

[00:18:23]The bodies that ran on these diets were not metabolically confused by the variability.

[00:18:27]They were metabolically optimized for it.

[00:18:30]The prehistoric metabolism was built around a fundamentally different relationship with fuel than the modern metabolism operates under. Modern nutritional guidelines, food systems, and eating patterns have trained the modern metabolism to expect a continuous supply of glucose from regularly spaced carbohydrate-rich meals.

[00:18:45]The modern body has largely lost the practiced ability to switch efficiently and rapidly between glucose metabolism and fat metabolism because it is almost never required to do so. Glucose is always available. The fat metabolism pathway has become undertrained, slow, and metabolically expensive to activate.

[00:19:01]The prehistoric metabolism switched between fuel sources continuously and without difficulty because it had no choice. When the hunt failed, glucose from carbohydrates became scarce, and the body shifted to fat oxidation and ketone production to maintain brain and muscle function.

[00:19:14]When fruit came into season or a large animal was killed, the body shifted back to glucose metabolism and simultaneously maximized fat storage against the next period of scarcity.

[00:19:23]This metabolic flexibility, the ability to shift rapidly and efficiently between fuel sources in response to availability, is a fundamental feature of the human metabolic system that modern dietary patterns have largely suppressed.

[00:19:35]The consequences of this suppression are visible in the metabolic disease data of industrialized populations.

[00:19:41]Type 2 diabetes, metabolic syndrome, non-alcoholic fatty liver disease, obesity-related cardiovascular disease.

[00:19:47]All of these conditions involve a failure of the metabolic flexibility that prehistoric humans maintained throughout their lives.

[00:19:53]The body that cannot efficiently switch to fat oxidation when glucose is unavailable is a body that cannot regulate blood glucose correctly when glucose is continuously available.

[00:20:01]The metabolic machinery exists. It simply has not been exercised in the way it requires.

[00:20:06]The specific detail that most dramatically illustrates the difference is the prehistoric relationship with fasting.

[00:20:12]Modern medical research on intermittent fasting, time-restricted eating, and extended fasting protocols has produced a body of evidence suggesting significant metabolic, inflammatory, and neurological benefits from periods of voluntary food restriction. These benefits appear to operate through mechanisms including autophagy, the cellular cleanup process that preferentially activates during fasting, ketone production which provides the brain with an alternative fuel source associated with enhanced cognitive function, and the down-regulation of inflammatory pathways that are up-regulated by continuous glucose availability. Prehistoric humans were intermittent fasting involuntarily and continuously throughout their lives.

[00:20:47]The metabolic and cellular maintenance processes that modern researchers are discovering through carefully controlled clinical protocols were simply the normal operating state of the prehistoric metabolism because the food environment made them unavoidable.

[00:20:58]The prehistoric body was not eating better food in some abstractly superior way. It was operating a metabolic system that was continuously exercised across its full functional range. Every mode of the system was used regularly. Nothing was allowed to become under-trained. The modern metabolism is a Formula 1 engine that has been driven exclusively in first gear for 10,000 years and then asked why it is not performing as designed. Number five, their bodies ran on a fuel system that made modern metabolism look broken.

[00:21:24]In 2000, physiologist Loren Cordain published a detailed analysis of the diets of 229 hunter-gatherer societies whose dietary patterns had been documented by anthropologists before significant contact with industrialized food systems.

[00:21:38]The analysis examined macronutrient ratios, food variety, meal timing, and the relationship between food availability and consumption patterns.

[00:21:46]The findings were not what nutritional orthodoxy of the time expected.

[00:21:50]Hunter-gatherer diets were not consistent. They were not three meals a day. They were not balanced in the sense that modern nutritional guidelines use that term.

[00:21:58]They were highly variable, seasonally driven, and included regular periods of involuntary fasting followed by periods of high caloric surplus when a hunt was successful or a plant food came into season.

[00:22:09]The bodies that ran on these diets were not metabolically confused by the variability.

[00:22:13]They were metabolically optimized for it.

[00:22:16]The prehistoric metabolism was built around a fundamentally different relationship with fuel than the modern metabolism operates under.

[00:22:22]Modern nutritional guidelines, food systems, and eating patterns have trained the modern metabolism to expect a continuous supply of glucose from regularly spaced carbohydrate-rich meals.

[00:22:31]The modern body has largely lost the practiced ability to switch efficiently and rapidly between glucose metabolism and fat metabolism because it is almost never required to do so. Glucose is always available. The fat metabolism pathways become under-trained, slow, and metabolically expensive to activate. The prehistoric metabolism switched between fuel sources continuously and without difficulty because it had no choice.

[00:22:53]When the hunt failed, glucose from carbohydrates became scarce and the body shifted to fat oxidation and ketone production to maintain brain and muscle function.

[00:23:01]When fruit came into season or a large animal was killed, the body shifted back to glucose metabolism and simultaneously maximized fat storage against the next period of scarcity.

[00:23:11]This metabolic flexibility, the ability to shift rapidly and efficiently between fuel sources in response to availability, is a fundamental feature of the human metabolic system that modern dietary patterns have largely suppressed.

[00:23:22]The consequences of this suppression are visible in the metabolic disease data of industrialized populations.

[00:23:28]Type 2 diabetes, metabolic syndrome, non-alcoholic fatty liver disease, obesity-related cardiovascular disease.

[00:23:35]All of these conditions involve a failure of the metabolic flexibility that prehistoric humans maintained throughout their lives.

[00:23:40]The body that cannot efficiently switch to fat oxidation when glucose is unavailable is a body that cannot regulate blood glucose correctly when glucose is continuously available.

[00:23:49]The metabolic machinery exists. It simply has not been exercised in the way it requires.

[00:23:54]The specific detail that most dramatically illustrates the difference is the prehistoric relationship with fasting.

[00:23:59]Modern medical research on intermittent fasting, time-restricted eating, and extended fasting protocols has produced a body of evidence suggesting significant metabolic, inflammatory, and neurological benefits from periods of voluntary food restriction. These benefits appear to operate through mechanisms including autophagy, the cellular cleanup process that preferentially activates during fasting, ketone production, which provides the brain with an alternative fuel source associated with enhanced cognitive function, and the downregulation of inflammatory pathways that are upregulated by continuous glucose availability. Prehistoric humans were intermittent fasting involuntarily and continuously throughout their lives.

[00:24:34]The metabolic and cellular maintenance processes that modern researchers are discovering through carefully controlled clinical protocols were simply the normal operating state of the prehistoric metabolism because the food environment made them unavoidable.

[00:24:45]The prehistoric body was not eating better food in some abstractly superior way. It was operating a metabolic system that was continuously exercised across its full functional range. Every mode of the system was used regularly. Nothing was allowed to become undertrained. The modern metabolism is a Formula 1 engine that has been driven exclusively in first gear for 10,000 years and then asked why it is not performing as designed. Number three, their muscles were built to a structural specification that modern training cannot replicate.

[00:25:12]In 1995, anthropologist Christopher Ruff published a comparative analysis of the long bone geometry of prehistoric hunter-gatherer populations against both early agricultural populations and modern humans from the same geographic regions.

[00:25:26]The analysis used cross-sectional geometric properties of the femur and tibia to estimate the mechanical loading histories of the individuals because bone geometry encodes the history of the forces applied to it across a lifetime with considerable precision. The results established what has since become one of the most replicated findings in bioarcheology.

[00:25:43]The transition from hunter-gatherer lifestyles to agricultural lifestyles caused a dramatic reduction in lower limb bone strength that is visible in the skeletal record across every studied population where the transition occurred. The bones of early farmers were significantly less robust than the bones of the hunter-gatherers they replaced in the same regions. And the bones of modern humans are less robust still. The muscle architecture that produced the bone geometry of prehistoric hunter-gatherers was not the muscle architecture produced by modern strength training. This is a distinction that requires careful explanation because it is counterintuitive. Modern strength training, including resistance training, powerlifting, and bodybuilding produces significant increases in muscle size and short duration force production.

[00:26:25]A modern strength athlete can produce very high peak forces in the specific movement patterns they train. But the muscle architecture produced by modern training is specialized for those specific patterns and those specific durations.

[00:26:36]It is not the same as the muscle architecture produced by a lifetime of varied, high-volume, low-to-moderate intensity physical work across the full range of human movement patterns.

[00:26:45]Prehistoric muscles were not bigger than modern trained muscles. In many cases, they were smaller in cross-section than the muscles of modern bodybuilders. What they were was differently constructed at the level of fiber type distribution, tendon insertion geometry, and the density and distribution of slow-twitch oxidative fibers that support sustained force production over hours rather than seconds. A modern strength athlete can deadlift 500 lb for one repetition. They cannot then walk 15 mi carrying a loaded pack, process a large animal carcass by hand, build a shelter, and repeat the process the following day without accumulated fatigue, degrading their performance across the week. Prehistoric humans did the equivalent of this routinely. The muscle system that supported it was built for duration and variety across an entire lifetime of varied physical demand, not for peak performance in a narrow window of specialized movement. The specific muscle group that most dramatically illustrates this difference is the posterior chain, the interconnected system of muscles running from the back of the heel through the hamstrings, gluteus, and lower back. This is the muscle group most directly responsible for bipedal locomotion, load carrying, throwing, and the sustained physical activities that define prehistoric life.

[00:27:50]In modern humans, posterior chain weakness is so common that it has its own clinical vocabulary. Gluteal amnesia, the failure of the glute muscles to activate correctly during basic movement, has been identified as a contributing factor in a substantial proportion of lower back pain, knee pain, and hip dysfunction in clinical populations. It occurs because modern sitting patterns and movement-reduced lifestyles allow the posterior chain muscles to become functionally dormant.

[00:28:13]The prehistoric posterior chain never had a day off. It did not know what dormant meant. The muscles that move a human being through the world were the most-used muscles in a prehistoric body's inventory, and they were used for everything, every day, from the moment physical independence was achieved until the body failed. The modern gym was invented because we removed the physical demand of daily life, and then had to invent a substitute. The prehistoric body never needed the substitute because it never lost the original.