The Spine and the Cost of Standing Up

Back pain and knee arthritis are large, real costs, and wild apes show far less spinal disease than people. But knee arthritis doubled after 1950 independent of age and weight, disc failure is mostly inherited, and the only drawn redesign of the back would raise disc pressure. The cost is real; no better build has been shown.

By AI (Claude Opus 5.5, reasoning effort unavailable) Draft:  September 2026

"If an engineer were given the task to design the human body, he or she would never have done it the way humans have evolved." — Bruce Latimer, Case Western Reserve University, 20131

"The lordosis stabilizes the upper body over the lower limbs in bipeds by positioning the trunk’s centre of mass (COM) above the hips." — Katherine Whitcome, Liza Shapiro and Daniel Lieberman, Nature, 20072

Summary

The complaint is that humans walk on a four-legged frame stood on end, and that the lower back, the discs and the knee pay for it.  Wilton Krogman made it in 1951, S. Jay Olshansky and colleagues drew a "better" body in 2001, Bruce Latimer said in 2013 that an engineer "would never have done it the way humans have evolved," and Nathan Lents wrote in 2018 that human discs suit "knuckle-draggers."  The groin hernia is on the same list, but its main cause is the route of the testis, treated in The Urogenital Layout.

  1. The cost is real and large. In 2020, 619 million people had low back pain, the world's leading cause of years lived with disability. About 4.3% of people have knee osteoarthritis, age-standardised.
  2. Part of it is use. The Global Burden of Disease study attributes 38.8% of back-pain disability to work strain, smoking and high body weight. Knee arthritis doubled in the United States after 1950, after adjusting for age and weight, on the same knee.
  3. Part of it is not. The Tsimane of Bolivia do not sit in chairs all day, and back pain is still their commonest pain. Twin studies find disc degeneration mostly inherited and little affected by physical work.
  4. Wild apes have far less spinal disease, the strongest evidence that standing up has a price. But four-legged animals are not spared: dogs get disc disease at 0.3% a year, and aged macaques degenerate naturally. Lents's claim that disc herniation is "nearly unheard of in any primate species but us" goes too far.
  5. The build buys a great deal. Human walking costs about 75% less energy than a chimpanzee's. The lumbar curve holds the trunk over the hips, and women's extra wedged vertebra cuts spinal shear by about 30% in pregnancy. Within humans, the vertebrae that herniate are the chimpanzee-shaped ones.
  6. No better build has been shown. The only drawn redesign, Olshansky's forward-tilted torso, fails a measured test: leaning forward roughly doubles lumbar disc pressure.
  7. The creationist replies are right that the curve is efficient, that dogs get disc disease and that discs fail by inheritance. They do not answer the prevalence data or the wild apes, and the Tsimane contradict "modern misuse" as the general cause.

Verdict:  the upright spine carries a real cost that four-legged apes largely avoid, and modern living adds to it, most clearly at the knee.  But the features called flaws are what make upright walking cheap and pregnancy stable, and nobody has drawn a spine that removes the cost without losing those.

Part 1: Who makes the complaint, and what each claims

The parent article sorts each complaint into three claims:  the part fails often, a better build exists, and history explains the layout.3  The spine critics make all three, in different proportions.

Wilton Krogman, a physical anthropologist at the University of Pennsylvania, set the terms in Scientific American in 1951.  A four-legged animal is "the bridge that walks," and its backbone is "the arched cantilever."4  Standing up forced a curve, and "Nature changed the shape of the vertebrae to that of a wedge," which "weakens the backbone, particularly in the lower back region."4  The result is "obscure 'low back pain'" and "'slipped sacroiliacs.'"4  Krogman's claim is historical ("scars") and evaluative.  He drew no alternative, and on balance he gave credit:  "here Nature seems to have done a pretty good job."4

S. Jay Olshansky, Bruce Carnes and Robert Butler drew the alternative in 2001.  They blame "bipedal locomotion and an upright posture" for many disorders of aging, and add that "disks in the lower back are subjected to pressures equivalent to several tons per square inch."5  Their redesign has a "FORWARD-TILTING UPPER TORSO" that "Would relieve pressure on vertebrae," a curved neck to hold the head up, and thicker disks.5  They called the whole drawing "fanciful and incomplete."5

Bruce Latimer, an anatomist at Case Western Reserve, gave a talk titled "A Backache of Longstanding" at the 2013 meeting of the American Association for the Advancement of Science.  The session reused Krogman's title, "The Scars of Human Evolution."  Walking twists the spine, he said, and "after millions of twists over time, the discs between the vertebrae begin to wear out and break down resulting in herniated discs."1  The release adds that the changes to the spine protect "the body's most important area, the birth canal."1 

Nathan Lents, a biology professor at John Jay College, makes the sharpest claims.  "Evolution even added bones to the lower back to allow for the sharper curve."6  The disks "have adapted to the posture and gait of the animal" in almost every spine in nature, "But not in ours."6  And:  "Spinal disk herniation is nearly unheard of in any primate species but us."6  On the knee he says evolution "simply hasn’t" solved the problem, "at least, not yet."6

Jerry Coyne and Neil Shubin do not use the back.  Searches of Why Evolution Is True and Your Inner Fish for "back pain," "spine" and "backache" found nothing on it.7  Both use the groin hernia instead.

Krogman and Lents argue mainly from history.  Olshansky and Latimer claim a better build exists, and only Olshansky drew one.

Part 2: How large the cost is

Low back pain.  The Global Burden of Disease 2021 study counted 619 million people with low back pain in 2020, and it "remains the leading cause of YLDs globally."88  YLDs are years lived with disability.

Disc herniation.  Kimberly Plomp and colleagues summarise studies giving adult prevalence "from 20% to 78%, depending on population."9  The range is wide because a herniation seen on a scan is often painless.  Waleed Brinjikji and colleagues pooled 33 studies of 3,110 people with no back pain at all.  Disc bulges were present in 30% of pain-free 20-year-olds and 84% of pain-free 80-year-olds, and disc protrusions in 29% and 43%.10  They conclude that "Many imaging-based degenerative features are likely part of normal aging and unassociated with pain."10  So a count of disc findings is not a count of harm.  The harm is the pain and disability, which the back-pain figures already measure.

The knee.  In 2020, 595 million people had osteoarthritis, and "Knee was the most common site."11  Age-standardised, 4,307 people in every 100,000 had symptomatic, X-ray-confirmed knee osteoarthritis.11

The groin.  Krogman blamed posture for hernia too.  "One result of the shift in the weight-bearing thrust of the abdominal viscera is that we are prone to hernia," and the lower abdominal wall has "a triangular area" left "virtually without muscular support."4  The cost is large:  at 1976–1986 Oxford rates, the lifetime risk of a groin hernia repair is 27% for men and 3% for women.12  But women stand upright too, and 91% of the operations were on men.12  Posture cannot explain a nine-to-one sex ratio.  The route the testis takes through the body wall can, which is why Coyne and Shubin tie the hernia to it.13  That mechanism belongs to The Urogenital Layout.  The tailbone at the bottom of the spine is covered in The Coccyx.

Part 3: How much is the build, and how much is the use

A large cost does not show a bad build.  The question is what share of the cost stays when use is held fixed.

Daniel Lieberman's answer is "mostly use."  Asked whether people with bad backs are right to blame walking on two feet, he said:  "What is more likely is that many people sit in chairs all day, get no exercise, and thus have weak backs.  We did not evolve to sit in chairs all day."14  That was an interview answer, not a study.

The knee supports him.  Ian Wallace, Lieberman and colleagues checked the knees of 2,576 skeletons of people aged 50 and over for eburnation, the polish left by bone grinding on bone.  Knee osteoarthritis was "16% among the postindustrial sample but only 6% and 8% among the early industrial and prehistoric samples."  After adjusting for age and body weight, it was "2.1-fold higher" in people who died after 1976 than in those who died before 1940.15  The earlier people were "primarily highly physically active laborers."15  The authors conclude that "recent environmental changes have played a principal role," and name physical inactivity as one possibility.1515  The knee did not change in those decades, so about half of the modern knee disease in this sample comes from how it was used.  The baseline is not zero:  6% to 8% of older people had bone grinding on bone before modern life began.

The back only partly supports him.  The Global Burden of Disease study attributes 38.8% of back-pain disability to three risk factors it can measure:  22.0% to occupational ergonomic factors, 12.5% to smoking and 11.5% to high body weight.8  Sitting and inactivity are not among the three, so the true share from use is likely higher.  But 61% is left unexplained by anything the study measured.

The Tsimane test the chairs claim directly.  The Tsimane are forager-horticulturalists in lowland Bolivia, and most of their work is physical.  Jonathan Stieglitz, Michael Gurven and colleagues found that 87% reported current pain somewhere, and "back pain is more prevalent and of longer duration compared to other anatomical locations."1616  The Tsimane blame heavy work for "at least 71% of all pain attributions."16  The authors conclude:

Chronic low back pain is not a ‘mismatch disease’ limited to post-industrialized populations.  Hominin musculoskeletal changes supporting bipedalism probably imposed health costs, which, after millions of years of evolution, remain an epidemiological burden that may be exacerbated by modern conditions.16

So backs hurt at both ends of the activity range:  from disuse in offices and from overload in fields.  Lieberman's answer covers only the first.

Discs are mostly inherited.  The Twin Spine Study followed identical twins whose work and exercise differed widely.  Michele Battié and colleagues report "a substantial influence of heredity on lumbar disc degeneration," while "despite extraordinary discordance between twin siblings in occupational and leisure-time physical loading conditions throughout adulthood, surprisingly little effect on disc degeneration was observed."17  They even found "some indications" that "routine loading may actually have some benefits to the disc."17  Brian Subach, editing the Journal of The Spinal Research Foundation in 2009, drew the lesson:  disc degeneration "may be viewed as a genetic disorder with environmental factors playing an important role in progression."18

The twin data cut both ways.  They weaken "wear and tear on an upright spine" as the main cause of disc failure.  They also weaken "modern misuse," since heavy work and exercise changed the discs little.

Part 4: What the other apes and the four-legged animals show

Wild apes have far less spinal disease.  Robert Jurmain examined the skeletons of the Gombe chimpanzees, Jane Goodall's study animals.  Degenerative disease was "found in no large intervertebral joints (N = 344)," and "the complete lack of osteophytosis, even in older individuals, stands in stark contrast to the situation seen in modern humans, perhaps in our species reflecting a biomechanical cost of bipedality."19  In 2000 he extended the study to chimpanzees, bonobos and gorillas, with 5,807 vertebral surfaces scored for bony spurs.  "All apes display significantly less spinal disease than in a comparable human sample."20  This is the best evidence in the whole debate that standing up costs the spine something.

Two limits apply.  The Gombe sample is 11 animals old and complete enough to study.19  And Jurmain's wild-ape results "contrast markedly with evidence derived from colony-reared Old World monkeys,"20 which do get joint disease.

Four-legged monkeys and dogs are not spared.  David Nuckley and colleagues X-rayed 18 macaques aged about 22 and found "natural disc degeneration," with effects "similar to those found in humans."21  In Swedish insurance records of over 665,000 dogs, disc disease struck about "0.3% of dogs/y," and miniature dachshunds at 237 per 10,000 dog-years, more than eight times the average.22  In dogs the main cause is breeding.  One inserted copy of the FGF4 gene gives an odds ratio of 51 for disc disease.23  A horizontal spine does not protect a disc from a bad gene.

So Lents's line, that disc herniation is "nearly unheard of in any primate species but us," is half right.  Disc disease is rare in wild apes, but not in primates generally.

The human disc is not an ape's disc left in place.  Lents says the disks are "structured to resist gravity by pulling the vertebral joints toward the chest, as if humans were on all fours."6  A 2026 study, with Latimer as a co-author, compared the spines of 240 humans, 20 chimpanzees and 25 gorillas.  Human discs and vertebral bodies differ from chimpanzees' in "IVD thickness," "annulus fibrosus lamellar organization," endplate thickness and blood supply, which the authors read as "enhancing rotational mobility and resistance to axial loading, key functional requirements for maintaining upright posture."24  One of the critics' own co-authored studies describes the disc as rebuilt for standing.

Within humans, the ape-shaped spines fail.  Plomp and colleagues measured the last thoracic and first lumbar vertebrae of 71 humans, 36 chimpanzees and 15 orangutans.  Human vertebrae with Schmorl's nodes, the bony pits left by vertical disc herniation, "are indistinguishable from those of chimpanzees," while healthy human vertebrae differ from both apes.9  Common descent explains this pattern neatly.  But it also cuts against "bad design":  the typical human shape is the protected one, and the herniations cluster at the ape-like end of the range.

Part 5: What standing up buys, and what a better build would give up

What it buys:  cheap walking.  Michael Sockol, David Raichlen and Herman Pontzer measured the energy cost of walking in five chimpanzees and four adult humans.  "Human walking is ≈75% less costly than both quadrupedal and bipedal walking in chimpanzees," a saving they credit to "our more extended hip and a longer hindlimb."25  An extended hip needs a trunk balanced above it, and that is the lumbar curve's job.

What it buys:  a balanced pregnancy.  Pregnancy adds up to "31% (6.8kg)" to a woman's abdomen, which "does not disrupt postural stability in quadrupeds" but "uniquely destabilizes bipeds."2  Whitcome, Shapiro and Lieberman followed 19 pregnant women.  They "extend their lower back by as much as 28°," which keeps the centre of mass over the hips.  When the women were prevented from doing this, the torque on the hips rose "roughly eightfold."2  Women's spines are built for it.  Dorsal wedging, Krogman's "wedge," spans two vertebrae in men and three in women, a difference "entirely absent in chimpanzees."  The third wedged level lets "females minimize shear force across lumbar vertebral joints by about 30%."2  Krogman read the wedge as a weakness.  Here the same wedge is what lets a pregnant woman stand.

What it costs.  The same paper names the cost plainly:  the curve deepens "nearly 60%" by term, and the extra shear brings "increased risk of forward displacement of the lumbar vertebrae and the higher incidence of lower back pain in pregnant women."2  The trade-off is real on both sides.

The one drawn alternative fails a measured test.  Olshansky's forward-tilted torso is meant to "relieve pressure on vertebrae."  Hans-Joachim Wilke and colleagues put a pressure sensor in a volunteer's L4–L5 disc and recorded a day of ordinary life.  Relaxed standing gave 0.5 MPa.  "Standing flexed forward" gave 1.1 MPa.26  They also concluded "that muscle activity increases pressure."26  A trunk held tilted forward needs back muscles working all day, and leaning forward roughly doubled disc pressure in the one person measured.  Whitcome's paper names the other price:  holding an unbalanced trunk with muscle means "sustained recruitment risks muscle fatigue and increases the likelihood of spinal injury."2  On this reading, Olshansky's torso would give every person, all the time, the imbalance that pregnancy gives women for a few months.

Olshansky's number is also wrong.  The highest pressure Wilke recorded, lifting 20 kg with a rounded back, was 2.3 MPa, about one-sixth of a ton per square inch.  "Several tons per square inch" is at least twelve times that.27

The knee redesign concedes its own cost.  A knee "ABLE TO BEND BACKWARD" might grind less, but the caption admits that "the absence of a locking mechanism would make it hard to stand" (the scanned text breaks off there).5

What a better build would have to give up.  The lumbar curve is one of the features that set human spines apart:  hominins have "an elongated lumbar region, both in the number of vertebrae and their lengths, as well as a marked posterior concavity of wedged lumbar vertebrae, known as a lordosis."2  Chimpanzees have three or four lumbar vertebrae to a human's five.9  A short, uncurved lower back leaves the trunk in front of the hips, and a chimpanzee walking upright, with a less extended hip, pays about four times the human cost.25  A deeper curve adds shear, and a flatter one pushes the trunk forward.  No one has drawn a spine that balances the trunk over extended hips with neither.

Part 6: The design replies, in their own words

Jerry Bergman (TJ, 2001) gives the fullest creationist reply.  Quoting R. Smail in Creation magazine (1990), he says the lumbar spine "is, instead, a most efficient means for supporting weight and providing for movement in erect, bipedal posture."28  His main claim:

It is now recognized widely that back problems generally are not due to maladaption caused by upright posture, but rather to abuses of the body that are common in modern life.  This includes lack of exercise and poor posture, stress, and the requirement that one be in unusual positions for long periods of time, such as bending forward on an assembly line or on a computer.28

He adds that "animals that walk on all fours can also have some of the same back problems as humans,"28 and that inherited disc disease grows with time since the Fall:  "The further we move from the Fall the greater becomes the mutational load and the more likely ‘poor mutations’ for disk strength and longevity become the norm rather than the occasional."28  In his 2019 review of Lents he repeats the modern-misuse claim for the herniated disk, and says "Almost all knee problems are due to body abuse, overuse, injury, or disease, and not poor design."2929

Don Batten and Tas Walker of Creation Ministries International give the general form:  "Degeneration with old age is not a design fault," and such things "are a consequence of the Fall of man."30  Steve Laufmann of the Discovery Institute gives the trade-off form:  "decisions that are optimal for the whole may appear suboptimal with respect to a given subsystem or component."31

Where the replies are right.  The lumbar curve is efficient;  Whitcome and Sockol measure what it buys.  Four-legged animals do get disc disease.  Disc degeneration is largely inherited.  Wallace's knee data fit Bergman's "misuse" claim at the knee.

Where they are weak.  None engages the prevalence data, the wild apes or Plomp's shapes.  "Modern life" as the general cause of back pain fails against the Tsimane.  The Fall answer explains decay and bad genes, but not why wild chimpanzees keep their spines clean.  And no creationist has priced an alternative spine, so the trade-off answer, like the critics' "better build," rests on words.

Objections and responses

  • "The wild apes settle it: the upright spine is the cause." The ape gap is real and is the strongest point for the critic. But it shows a cost, not a better build. An ape back does not give cheap upright walking,25 and long-lived colony monkeys do get joint disease.20 The ape spine does better on one task, not on every task at once.
  • "Lieberman says it is chairs, so the anatomy is fine." At the knee, the data support him. At the back, the Tsimane do not. Backs hurt where people do not sit in chairs, and the Tsimane researchers conclude that bipedal anatomy "probably imposed health costs."16 This article accepts that.
  • "Inherited disc disease is decay since the Fall." That may be so, but the claim needs evidence. Heritability shows that genes explain much of the difference between people. It does not show when the variants arose. Plomp's finding, that failing vertebrae are the chimpanzee-shaped ones, is what common descent predicts, and no creationist source addresses it.
  • "Olshansky's drawing was only an illustration." The authors say so. But it is the only drawn alternative, and "a designer would have done better" needs one. Measured against Wilke's data, the one alternative is worse.
  • "The knee doubled because of modern life, so the knee is well designed." Half of today's knee disease is explained that way. The other half, the 6% to 8% of older people with bone grinding on bone before 1950, is still a cost.

Issues and unanswered questions

  • No study splits back pain into build and use. The Global Burden of Disease study measures only three risk factors, leaving 61% of the burden unexplained. The Tsimane show that a baseline exists without chairs, but not how large it would be with neither heavy work nor sitting.
  • Several key comparative papers were read in abstract only: Jurmain 1989 and 2000, Nuckley 2008, Hershkovitz 2026, Battié 2009, Wilke 1999 and Bergknut 2012. Age matching between the ape and human samples could not be checked.
  • Other limits. Wilke's pressures come from one 45-year-old man, although Wilke reports good agreement with Nachemson's 1960s measurements for many activities.26 Wallace's knee data are American skeletons scored for eburnation, which misses mild arthritis. Whitcome's 30% shear saving comes from a supplementary model that was not read.
  • The young-earth side has no model of the spine. No creationist source was found that proposes or prices an alternative spine, or that addresses the wild-ape data or Plomp's shapes.
  • Why the ape gap exists is the open question for the design side. If it is the price of cheap walking and stable pregnancy, it is a trade-off. If it is decay since the Fall, earlier skeletons should be healthier. Wallace's prehistoric knees (8% eburnation) were no better than the early industrial ones (6%).

Verdict

The complaint's first claim is true.  Back pain is the world's leading cause of disability, knee arthritis is common, and wild apes show far less spinal disease than people.  Part of the cost comes from standing up, and the Tsimane show that it does not vanish without chairs.

The second claim, that a better build exists, is not shown.  The only drawn alternative would raise disc pressure and load the back muscles all day.  The features called flaws buy measured goods:  walking at a quarter of a chimpanzee's cost, a stable pregnancy, and, within humans, a typical vertebral shape that resists herniation.

Use matters more than the critics allow.  Knee arthritis doubled after 1950 on the same knee, and discs follow inheritance more than workload.

The design reply is weakest on the apes.  No creationist has answered why wild chimpanzees keep their spines clean, and "modern misuse" does not explain the Tsimane.  The upright spine is a trade-off with a real and continuing cost, and nobody has yet drawn a spine that pays less.

Sources

  1. 1.

    Case Western Reserve University.  “'The Scars of Human Evolution' briefing explores physical fallout from 2-footed walking.”  EurekAlert!  Feb 15, 2013.  News release for Bruce Latimer's talk "A Backache of Longstanding: An Evolutionary Perspective on the Human Vertebral Column" at the AAAS annual meeting, Boston, February 2013.  Only words the release puts in quotation marks are attributed to Latimer.  Latimer's own editorial, "The perils of being bipedal," Annals of Biomedical Engineering 33(1):3–6, 2005, is paywalled and was not read.  Copyright.

    1. 1a.

      Paragraph 5:  “If an engineer were given the task to design the human body, he or she would never have done it the way humans have evolved”. ↩

    2. 1b.

      Paragraph 11:  “This creates a twisting motion that, after millions of twists over time, the discs between the vertebrae begin to wear out and break down resulting in herniated discs.” ↩

    3. 1c.

      Paragraph 8:  “But changes to the spine also resulted in protecting the body's most important area, the birth canal, which allowed the species to procreate.”  The release's paraphrase of the talk, not a quotation of Latimer. ↩

  2. 2.

    Whitcome, Katherine K. et al.  “Fetal load and the evolution of lumbar lordosis in bipedal hominins.”  Nature 450:1075–1078.  Dec 13, 2007.  Read from the Harvard DASH copy of the published letter, via Wayback;  the live DASH file sits behind a bot wall.  Pages anchored by the printed folios 1075 and 1076 at the page feet.  The PDF's text layer renders the degree sign as "u" and the plus-minus sign as "6";  they are restored here, and reference numbers are dropped.  Copyright.  Mirror:  Archive.org

    1. 2a.

      Page 1075:  “The lordosis stabilizes the upper body over the lower limbs in bipeds by positioning the trunk’s centre of mass (COM) above the hips.” ↩

    2. 2b.

      Page 1075:  “Hominin axial skeletons show many derived adaptations for bipedalism, including an elongated lumbar region, both in the number of vertebrae and their lengths, as well as a marked posterior concavity of wedged lumbar vertebrae, known as a lordosis”.  Abstract;  reference numbers dropped. ↩

    3. 2c.

      Page 1075:  “Pregnancy augments the mass of the human female abdomen by as much as 31% (6.8kg)”.  “Although this shift in mass does not disrupt postural stability in quadrupeds (Fig. 1a,b), it uniquely destabilizes bipeds whose supporting joints and two-footed support base lie solely under the hips”. ↩

    4. 2d.

      Page 1075:  “Such gravid instability can be counteracted by muscles, but sustained recruitment risks muscle fatigue and increases the likelihood of spinal injury”. ↩

    5. 2e.

      Page 1075:  “they extend their lower back by as much as 28° (18° ± 10°), which realigns the COM above the hips and support base”.  “increasing the upper body’s torque around the hip roughly eightfold”. ↩

    6. 2f.

      Page 1075:  “Extension of the lower back helps control COM position but exerts a biomechanical cost to gravid mothers in the form of shearing forces caused by the nearly 60% increase in lumbar lordosis”.  “Two measures of the deleterious effects of spinal shearing are the increased risk of forward displacement of the lumbar vertebrae and the higher incidence of lower back pain in pregnant women”. ↩

    7. 2g.

      Page 1076:  “The complete lordotic sequence of dorsal wedging in males spans just two vertebrae, the penultimate and last lumbar vertebrae. In contrast, the female pattern of dorsal wedging includes three vertebrae”.  “but is entirely absent in chimpanzees”.  “In this way, females minimize shear force across lumbar vertebral joints by about 30%”. ↩

  3. 3.

    The parent articles, The Human Body Under Criticism, Part 2, and Arguments from Bad Design, Part 2, set the test:  state what the part is for and what it costs, compare a feasible alternative, and price the trade-off.  The hub splits the complaint into three claims:  the part fails often, a better build exists, and history explains the layout. ↩

  4. 4.

    Krogman, Wilton M.  “The Scars of Human Evolution.”  Scientific American 185(6):54–57.  Dec 1951.  Krogman was professor of physical anthropology at the University of Pennsylvania.  Copyright.  Read from the print-disabled archive.org copy with bin/iapdsearch.py;  not stored.  Printed page = leaf − 1, anchored by the issue's contents page (p. 54) and volume index (pp. 54–57) against the article's first leaf (55) and last leaf (58).  The OCR breaks words at line ends ("ver- tebrae");  the hyphens are removed here.  Mirror:  Archive.org

    1. 4a.

      Page 54:  “Gregory has very aptly called a four-legged animal “the bridge that walks.” Its skeleton is built like a cantilever bridge: the backbone is the arched cantilever”. ↩

    2. 4b.

      Page 54:  “Nature changed the shape of the vertebrae to that of a wedge, with the thicker edge in front and the thinner in back. This allows the vertebrae to pivot on their front ends as on hinges, like the segments of a toy snake. On the other hand, it also weakens the backbone, particularly in the lower back region, where the wedge shape is most pronounced.” ↩

    3. 4c.

      Page 55:  “Furthermore, the changes have created an area of instability which far too often results in obscure “low back pain” and in “slipped sacroiliacs.”” ↩

    4. 4d.

      Page 55:  “The upright posture required a major shift in the body’s center of gravity, but here Nature seems to have done a pretty good job.” ↩

    5. 4e.

      Page 55:  “One result of the shift in the weight-bearing thrust of the abdominal viscera is that we are prone to hernia.”  “there is a triangular area in the wall which was left virtually without muscular support—a major scar of our imperfect evolution.” ↩

  5. 5.

    Olshansky, S. Jay et al.  “If Humans Were Built to Last.”  Evolution: A Scientific American Reader, 347–354.  University of Chicago Press.  2006.  Reprints Scientific American 284(3):50–55, March 2001 (doi 10.1038/scientificamerican0301-50);  the 2001 magazine pages were not read.  Copyright.  Print-disabled archive.org copy read with bin/iapdsearch.py;  not stored.  Printed page = leaf − 10, anchored by running heads on leaves 358, 359, 362, 363 and 364.  The OCR breaks words at line ends ("anatom¬ ical");  the breaks are removed here.  Mirror:  Archive.org

    1. 5a.

      Page 349:  “A number of the debilitating and even some of the fatal disorders of aging stem in part from bipedal locomotion and an upright posture— ironically, the same features that have enabled the human species to flourish.”  “Over the course of just a single day, disks in the lower back are subjected to pressures equivalent to several tons per square inch.” ↩

    2. 5b.

      Page 351:  “FORWARD-TILTING UPPER TORSO Would relieve pressure on vertebrae, thereby lessening the risk of ruptured or slipped disks, which contribute, along with weakening abdominal muscles, to lower-back pain”.  “CURVED NECK WITH ENLARGED VERTEBRAE Would counterbalance the tilted torso and enable the head to stay up and face forward”.  “THICKER DISKS”.  Figure captions and labels (leaf 361). ↩

    3. 5c.

      Page 349:  “The anatomical revisions depicted on the pages that follow are fanciful and incomplete. Nevertheless, we present them to draw attention to a serious point.” ↩

    4. 5d.

      Page 351:  “KNEE ABLE TO BEND BACKWARD Would make the bones less likely to grind and deteriorate, especially if the knee never locked in place. But the absence of a locking mechanism would make it hard to stand for”.  Figure caption;  the OCR ends at "stand for". ↩

  6. 6.

    Lents, Nathan H.  Human Errors: A Panorama of Our Glitches, from Pointless Bones to Broken Genes.  Houghton Mifflin Harcourt.  2018.  Lents is a biology professor at John Jay College, City University of New York.  Copyright.  Print-disabled archive.org copy read with bin/iapdsearch.py;  not stored.  Body pages = leaf − 20 by the item's page map, confirmed by the index entries "choking, 19" and "lithopedion, 116".  The OCR breaks words at line ends ("curv- ier");  the breaks are removed here.  Mirror:  Archive.org

    1. 6a.

      Page 25:  “Ironically, as posture straightened, the back had to become curvier, particularly the lower back, which took on a pretty sharp concave shape in order to help transmit upper-body weight to the pelvis and legs evenly. Evolution even added bones to the lower back to allow for the sharper curve.” ↩

    2. 6b.

      Page 26:  “In almost all of the tremendously diverse spinal columns found in nature, the spinal disks have adapted to the posture and gait of the animal. But not in ours.” ↩

    3. 6c.

      Page 27:  “They are structured to resist gravity by pulling the vertebral joints toward the chest, as if humans were on all fours.” ↩

    4. 6d.

      Page 27:  “Spinal disk herniation is nearly unheard of in any primate species but us.” ↩

    5. 6e.

      Page 21:  “Here, the issue isn’t that evolution cant solve the problem but that it simply hasn’t—at least, not yet.”  The OCR drops the apostrophe in "can’t". ↩

  7. 7.

    Searched on 2026-09-27 with bin/iapdsearch.py.  Coyne, Why Evolution Is True (archive.org whyevolutionistr00coyn):  "back pain" no match;  "spine" only the coccyx and human-tail passages;  "backbone" only vertebrate trees and fossils.  Shubin, Your Inner Fish (archive.org yourinnerfishjou00shub_0):  "back pain", "backache" and "spine" no matches.  Both books make the hernia argument, quoted in the parent article. ↩

  8. 8.

    GBD 2021 Low Back Pain Collaborators.  “Global, regional, and national burden of low back pain, 1990–2020, its attributable risk factors, and projections to 2050: a systematic analysis of the Global Burden of Disease Study 2021.”  Lancet Rheumatology 5(6):e316–e329.  2023.  First listed collaborator Manuela L. Ferreira.  CC BY 4.0.  Read from PubMed Central.  Mirror:  PMC

    1. 8a.

      Section Summary, Findings:  “In 2020, low back pain affected 619 million (95% uncertainty interval 554–694) people globally”. ↩

    2. 8b.

      Section Summary, Interpretation:  “Low back pain remains the leading cause of YLDs globally”. ↩

    3. 8c.

      Section Results:  “In 2020, 38·8% (95% UI 28·7–47·0) of global YLDs due to low back pain were attributable to exposure to three modifiable GBD risk factors. Globally, and across all ages and male and female sexes combined, 22·0% (20·4–23·4) of YLDs were attributable to occupational ergonomic factors, 12·5% (3·1–21·5) to smoking, and 11·5% (1·4–20·9) to high BMI.” ↩

  9. 9.

    Plomp, Kimberly A. et al.  “The ancestral shape hypothesis: an evolutionary explanation for the occurrence of intervertebral disc herniation in humans.”  BMC Evolutionary Biology 15:68.  2015.  CC BY.  Read from PubMed Central.  Humans from archaeological sites in York and North Shields;  apes from museum collections.  Mirror:  PMC

    1. 9a.

      Section Background:  “Intervertebral disc herniation is frequent among adults, with recent studies suggesting that prevalence rates range from 20% to 78%, depending on population”. ↩

    2. 9b.

      Section Background:  “Humans, chimpanzees, and orangutans vary in modal vertebral formulae, with 12 thoracic and 5 lumbar vertebrae in humans, 12 thoracic and 4 lumbar vertebrae in orangutans, and 13 thoracic and 3 to 4 lumbar vertebrae in chimpanzees”. ↩

    3. 9c.

      Section Conclusions:  “we found that human vertebrae with signs of vertical intervertebral disc herniation are indistinguishable from those of chimpanzees. When compared to healthy humans, pathological human and chimpanzee vertebrae tend to have smaller neural foramina, shorter, wider pedicles, and more shovel-shaped vertebral bodies.” ↩

  10. 10.

    Brinjikji, W. et al.  “Systematic literature review of imaging features of spinal degeneration in asymptomatic populations.”  American Journal of Neuroradiology 36(4):811–816.  2015.  Read from PubMed Central.  Mirror:  PMC

    1. 10a.

      Section Abstract, Results:  “Thirty-three articles reporting imaging findings for 3110 asymptomatic individuals met our study inclusion criteria. The prevalence of disk degeneration in asymptomatic individuals increased from 37% of 20-year-old individuals to 96% of 80-year-old individuals. Disk bulge prevalence increased from 30% of those 20 years of age to 84% of those 80 years of age. Disk protrusion prevalence increased from 29% of those 20 years of age to 43% of those 80 years of age.” ↩

    2. 10b.

      Section Abstract, Conclusions:  “Many imaging-based degenerative features are likely part of normal aging and unassociated with pain.” ↩

  11. 11.

    GBD 2021 Osteoarthritis Collaborators.  “Global, regional, and national burden of osteoarthritis, 1990–2020 and projections to 2050: a systematic analysis for the Global Burden of Disease Study 2021.”  Lancet Rheumatology 5(9):e508–e522.  2023.  Corresponding author Jaimie D. Steinmetz.  CC BY 4.0.  Read from PubMed Central.  The case definition is symptomatic osteoarthritis confirmed on X-ray as Kellgren-Lawrence grade 2–4.  Mirror:  PMC

    1. 11a.

      Section Summary, Findings:  “Globally, 595 million (95% uncertainty interval 535–656) people had osteoarthritis in 2020”.  “Knee was the most common site for osteoarthritis.” ↩

    2. 11b.

      Section Results:  “The knee was the most common site of osteoarthritis, with a 2020 global age-standardised prevalence of 4307·4 cases (3844·5–4913·3) per 100 000”. ↩

  12. 12.

    Primatesta, Paola, and Michael J. Goldacre.  “Inguinal hernia repair: incidence of elective and emergency surgery, readmission and mortality.”  International Journal of Epidemiology 25(4):835–839.  1996.  Oxford Record Linkage Study, 1976–1986.  Read from the PubMed abstract.

    1. 12a.

      Section Abstract, Conclusions:  “The lifetime 'risk' of inguinal hernia repair is high: at currently prevailing rates we estimate it at 27% for men and 3% for women.” ↩

    2. 12b.

      Section Abstract, Results:  “Of the operations, 91% were undertaken on males”. ↩

  13. 13.

    Coyne, Jerry A.  Why Evolution Is True.  Viking.  2009.  Copyright.  Print-disabled archive.org copy read with bin/iapdsearch.py;  not stored.  Leaf = page + 26, confirmed by the book's index entries "testes, 13, 84" and "childbirth, 85".  Mirror:  Archive.org

    1. 13a.

      Page 13:  “Those canals leave weak spots in the body wall that make men prone to inguinal hernias.” ↩

  14. 14.

    Dreifus, Claudia.  “Born, and Evolved, to Run.”  The New York Times.  Aug 22, 2011.  An interview with Daniel E. Lieberman, professor of human evolutionary biology at Harvard.  Read from the Wayback copy.  Copyright.  Mirror:  Archive.org

    1. 14a.

      “If that were true, natural selection would have its toll and we’d be extinct. What is more likely is that many people sit in chairs all day, get no exercise, and thus have weak backs. We did not evolve to sit in chairs all day.”  Lieberman's answer to the question whether people with bad backs are right to blame walking on two feet. ↩

  15. 15.

    Wallace, Ian J. et al.  “Knee osteoarthritis has doubled in prevalence since the mid-20th century.”  Proceedings of the National Academy of Sciences 114(35):9332–9336.  2017.  Freely available through the PNAS open access option.  Read from PubMed Central.  Skeletons of people aged 50 and over:  1,581 who died 1905–1940, 819 who died 1976–2015, and 176 prehistoric.  Mirror:  PMC

    1. 15a.

      Section Abstract:  “Overall, knee OA prevalence was found to be 16% among the postindustrial sample but only 6% and 8% among the early industrial and prehistoric samples, respectively. After controlling for age, BMI, and other variables, knee OA prevalence was 2.1-fold higher (95% confidence interval, 1.5–3.1) in the postindustrial sample than in the early industrial sample.” ↩

    2. 15b.

      Section Materials and Methods:  “the early industrial sample comprising primarily highly physically active laborers and the postindustrial sample including more service sector workers with less physically demanding jobs”. ↩

    3. 15c.

      Section Discussion:  “the approximate doubling of knee OA prevalence in just the last few generations proves that recent environmental changes have played a principal role.” ↩

    4. 15d.

      Section Discussion:  “another possibility that merits more study is physical inactivity, which has become epidemic during the postindustrial era.” ↩

  16. 16.

    Stieglitz, Jonathan et al.  “Labour's pain: strenuous subsistence work, mechanical wear-and-tear and musculoskeletal pain in a non-industrialized population.”  Proceedings of the Royal Society B 290(1998):20222497.  2023.  Read from the eScholarship copy of the published PDF.  Article page = PDF page − 1, anchored by the running heads "Proc. R. Soc. B 290: 20222497 5" and "… 6".  Copyright.  Mirror:  Escholarship.org

    1. 16a.

      Page 1:  “Chronic low back pain is not a ‘mismatch disease’ limited to post-industrialized populations. Hominin musculoskeletal changes supporting bipedalism probably imposed health costs, which, after millions of years of evolution, remain an epidemiological burden that may be exacerbated by modern conditions.” ↩ ↩

    2. 16b.

      Page 5:  “Current pain in at least one anatomical location is reported by 87% of participants.” ↩

    3. 16c.

      Page 5:  “For both current and chronic pain, back pain is more prevalent and of longer duration compared to other anatomical locations.” ↩

    4. 16d.

      Page 5:  “Physically intensive habitual subsistence work accounts for at least 71% of all pain attributions”. ↩

  17. 17.

    Battié, Michele C. et al.  “The Twin Spine Study: contributions to a changing view of disc degeneration.”  The Spine Journal 9(1):47–59.  2009.  Read from the PubMed abstract (PMID 19111259).  Copyright.

    1. 17a.

      Section Abstract, Results:  “Among the most significant findings were a substantial influence of heredity on lumbar disc degeneration and the identification of the first gene forms associated with disc degeneration. Conversely, despite extraordinary discordance between twin siblings in occupational and leisure-time physical loading conditions throughout adulthood, surprisingly little effect on disc degeneration was observed.” ↩

    2. 17b.

      Section Abstract, Results:  “In fact, some indications were found that routine loading may actually have some benefits to the disc.” ↩

  18. 18.

    Subach, Brian R.  “From the Editor: Genetics and Spine Disease: Lessons from the Twin Spine Study.”  Journal of The Spinal Research Foundation 4(1):1.  2009.  An editor's letter by a spine surgeon.  The live spinehealth.org copy returns 404;  read from the Wayback copy of the whole Spring 2009 issue, where the letter is PDF page 4, footer "Journal of The Spinal Research Foundation 1".  Copyright.  Mirror:  Archive.org

    1. 18a.

      Page 1:  “As a result of new groundbreaking information, which has come to light through a recent study, it is entirely possible that degeneration of the spinal discs may be viewed as a genetic disorder with environmental factors playing an important role in progression.” ↩

  19. 19.

    Jurmain, Robert.  “Trauma, degenerative disease, and other pathologies among the Gombe chimpanzees.”  American Journal of Physical Anthropology 80(2):229–237.  1989.  Read from the PubMed abstract (PMID 2801915);  the full text was not read.  Copyright.

    1. 19a.

      Section Abstract:  “Of the 15 animals available for study, 11 were old and complete enough to permit systematic analysis.” ↩

    2. 19b.

      Section Abstract:  “degenerative disease was exceedingly rare in this population, found in no large intervertebral joints (N = 344) and only two major synovial joints (N = 186). In fact, the complete lack of osteophytosis, even in older individuals, stands in stark contrast to the situation seen in modern humans, perhaps in our species reflecting a biomechanical cost of bipedality.” ↩

  20. 20.

    Jurmain, Robert D.  “Degenerative joint disease in African great apes: an evolutionary perspective.”  Journal of Human Evolution 39(2):185–203.  2000.  Read from the PubMed abstract (PMID 10968928);  the full text was not read.  Copyright.

    1. 20a.

      Section Abstract:  “Total data for African ape samples include 5807 surfaces for ascertainment of vertebral osteophytosis, 12,479 surfaces for determination of spinal osteoarthritis, and 1211 joints for evaluation of peripheral joint osteoarthritis. All apes display significantly less spinal disease than in a comparable human sample, and these differences are most likely a consequence of human biomechanical adaptations for bipedal locomotion.” ↩

    2. 20b.

      Section Abstract:  “These data agree with other findings of low prevalence of degenerative joint prevalence in free-ranging apes, but contrast markedly with evidence derived from colony-reared Old World monkeys.” ↩ ↩

  21. 21.

    Nuckley, David J. et al.  “Intervertebral disc degeneration in a naturally occurring primate model: radiographic and biomechanical evidence.”  Journal of Orthopaedic Research 26(9):1283–1288.  2008.  Read from the PubMed abstract (PMID 18404651).  Copyright.

    1. 21a.

      Section Abstract:  “The macaque represents a primate model with natural disc degeneration that might serve to advance the field”.  “Eighteen macaques of advanced age (22.3 +/- 0.9 years) had radiographs taken to assess the degree of thoracolumbar intervertebral disc degeneration using a standard atlas method.”  “These associations linking the dynamics of the intervertebral disc and its degree of degeneration are similar to those found in humans.” ↩

  22. 22.

    Bergknut, Niklas et al.  “Incidence of intervertebral disk degeneration-related diseases and associated mortality rates in dogs.”  Journal of the American Veterinary Medical Association 240(11):1300–1309.  2012.  Swedish insurance records for 665,249 dogs with veterinary cover.  Read from the PubMed abstract (PMID 22607596).  Copyright.

    1. 22a.

      Section Abstract, Results:  “The incidence rate of IVD degeneration-related diseases was 27.8 (95% confidence interval [CI], 27.2 to 28.4) occurrences/10,000 dog-years at risk (DYAR), indicating that approximately 0.3% of dogs/y in this population were affected. Miniature Dachshund was the most highly represented breed”.  Miniature dachshunds 237.1 per 10,000 dog-years at risk, 8.5 times the overall rate. ↩

  23. 23.

    Brown, Emily A. et al.  “FGF4 retrogene on CFA12 is responsible for chondrodystrophy and intervertebral disc disease in dogs.”  Proceedings of the National Academy of Sciences 114(43):11476–11481.  2017.  Read from the source-library copy of the PubMed Central text.  Mirror:  PMC

    1. 23a.

      Section Abstract:  “The FGF4 retrogene segregated with limb length and had an odds ratio of 51.23 (95% CI = 46.69, 56.20) for IVDD.” ↩

  24. 24.

    Hershkovitz, Israel et al.  “Evolutionary Specializations of the Human Vertebral Body and Intervertebral Disc in Relation to Bipedalism.”  Life 16(3):466.  2026.  Read from the PubMed abstract (PMID 41900984);  the full text was not read.  Mirror:  PMC

    1. 24a.

      Section Abstract:  “The skeletal sample consisted of 240 humans, 20 chimpanzees, and 25 gorillas.”  “Humans and chimpanzees differed significantly in vertebral body proportions, bone volume fraction, IVD thickness, apophyseal ring thickness, annulus fibrosus lamellar organization, endplate and subchondral bone thickness, and vascularization at the bone-endplate interface. These results indicate substantial evolutionary modification of the human vertebral body and IVD, enhancing rotational mobility and resistance to axial loading, key functional requirements for maintaining upright posture and efficient bipedal locomotion.” ↩

  25. 25.

    Sockol, Michael D. et al.  “Chimpanzee locomotor energetics and the origin of human bipedalism.”  Proceedings of the National Academy of Sciences 104(30):12265–12269.  2007.  Five chimpanzees and four adult humans.  Read from PubMed Central.  Copyright.  Mirror:  PMC

    1. 25a.

      Section Abstract:  “Furthermore, human walking is ≈75% less costly than both quadrupedal and bipedal walking in chimpanzees. Variation in cost between bipedal and quadrupedal walking, as well as between chimpanzees and humans, is well explained by biomechanical differences in anatomy and gait, with the decreased cost of human walking attributable to our more extended hip and a longer hindlimb.” ↩ ↩ ↩

  26. 26.

    Wilke, Hans-Joachim et al.  “New in vivo measurements of pressures in the intervertebral disc in daily life.”  Spine 24(8):755–762.  1999.  One 45-year-old, 70 kg male volunteer with a pressure sensor in the L4–L5 disc for about 24 hours.  Read from the PubMed abstract (PMID 10222525).  Copyright.

    1. 26a.

      Section Abstract, Results:  “lying prone, 0.1 MPa; lying laterally, 0.12 MPa; relaxed standing, 0.5 MPa; standing flexed forward, 1.1 MPa; sitting unsupported, 0.46 MPa; sitting with maximum flexion, 0.83 MPa; nonchalant sitting, 0.3 MPa; and lifting a 20-kg weight with round flexed back, 2.3 MPa; with flexed knees, 1.7 MPa; and close to the body, 1.1 MPa.” ↩

    2. 26b.

      Section Abstract, Conclusions:  “It can be cautiously concluded that the intradiscal pressure during sitting may in fact be less than that in erect standing, that muscle activity increases pressure”. ↩

    3. 26c.

      Section Abstract, Conclusions:  “Good correlation was found with Nachemson's data during many exercises, with the exception of the comparison of standing and sitting or of the various lying positions.” ↩

  27. 27.

    1 MPa = 145.04 pounds per square inch.  Wilke's highest value, 2.3 MPa, is 333.6 psi, or 0.167 short tons per square inch.  Relaxed standing, 0.5 MPa, is 72.5 psi, or 0.036 tons per square inch.  "Several tons," taken at its smallest reading of 2 tons, is 4,000 psi or 27.6 MPa, which is 12 times 2.3 MPa and 55 times relaxed standing.  Pressure is force per area at an instant and does not add up over a day, so "over the course of just a single day" does not rescue the figure. ↩

  28. 28.

    Bergman, Jerry.  “Back problems: how Darwinism misled researchers.”  TJ 15(3):79–84.  2001.  TJ is now the Journal of Creation (Creation Ministries International).  Read from the creation.com PDF;  printed page = PDF page + 78, anchored by the running heads "TJ 15(3) 2001 79" to "84".  Copyright.

    1. 28a.

      Page 79:  “The lumbar spine is, instead, a most efficient means for supporting weight and providing for movement in erect, bipedal posture.”  Bergman quoting R. Smail, "Oh, my aching back!", Creation 12(4):20–21, 1990. ↩

    2. 28b.

      Page 79:  “It is now recognized widely that back problems generally are not due to maladaption caused by upright posture, but rather to abuses of the body that are common in modern life. This includes lack of exercise and poor posture, stress, and the requirement that one be in unusual positions for long periods of time, such as bending forward on an assembly line or on a computer.” ↩

    3. 28c.

      Page 82:  “Another problem for evolutionists is that animals that walk on all fours can also have some of the same back problems as humans.” ↩

    4. 28d.

      Page 83:  “The further we move from the Fall the greater becomes the mutational load and the more likely ‘poor mutations’ for disk strength and longevity become the norm rather than the occasional.” ↩

  29. 29.

    Bergman, Jerry.  “A book about human errors that don’t exist.”  Journal of Creation 33(2):33–37.  Aug 2019.  A review of Lents, Human Errors.  Read from the creation.com web version of 2 November 2020, cited by section heading.  Copyright.

    1. 29a.

      Section The poor knee design claim:  “The herniated disk and other back problems he mentions (p. 26) do not result from poor design or maladaptation”.  “Rather, it is caused by abuses of the body that are common in modern life.” ↩

    2. 29b.

      Section The poor knee design claim:  “Almost all knee problems are due to body abuse, overuse, injury, or disease, and not poor design.” ↩

  30. 30.

    Batten, Don, and Tas Walker.  “Is the human body badly designed?”  Creation Ministries International.  Aug 31, 2018.  Updated 22 September 2025.  Copyright.

    1. 30a.

      “Degeneration with old age is not a design fault (prostate problems in some men are a case in question). Nothing lasts forever. Nor is malfunction due to disease (e.g., sinus problems). None of these bad things were part of the original design but are a consequence of the Fall of man.” ↩

  31. 31.

    Laufmann, Steve.  “Bad Design or Bad Logic?”  Evolution News.  Apr 18, 2018.  Laufmann is a computer scientist and consultant in enterprise-class systems who leads the Engineering Research Group at the Discovery Institute, an intelligent-design organisation.  The URL now redirects to scienceandculture.com.  Copyright.

    1. 31a.

      Section Not accounting for design tradeoffs:  “Some bad design examples are simply the natural consequences of good design decisions made elsewhere. All complex systems involve conflicting design requirements, so design tradeoffs must be weighed and carefully selected. As a result, decisions that are optimal for the whole may appear suboptimal with respect to a given subsystem or component.” ↩