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Born not to run but to reproduce

Discussion in 'General Issues and Discussion Forum' started by scotfoot, Jun 25, 2016.

  1. scotfoot

    scotfoot Well-Known Member

    Members do not see these Ads. Sign Up.
    So why are we the shape we are . Why are feet the shape they are and why is the human scapula configure as it is . Yes they respectively allow us to run and throw but I believe these may not be the primary driving evolutionary forces .

    Monolith apart I think Kubrick sums things up nicely in this clip .

    2001: A Space Odyssey - The Dawn of Man - YouTube
    ▶ 9:34
    4 Apr 2015 - Uploaded by Art History
    This scene shows the beginning of the Paleolithic Era, and reveals that, by the usage of tools, man could stop ...

    No matter how well a person could run in a persistence hunt , if another guy turned up at the camp with feet that made him more agile and a shoulder that allowed him to wield a club more effectively, he would get the girl .

  2. scotfoot

    scotfoot Well-Known Member

    With regard to the above ,if you don't have time to watch the clip it can be summed up thus . A group of apes is in possession of a water hole from which the are subsequently chased by a more powerful group . The leader of the dispossessed group then has a eureka moment and figures out that large bones can be used as weapons so he and his troop manage to retake the water hole .

    The assumption seems to be that the dawn of man is a cerebral event not a skeletal one .

    However it is hypothesized by many that the common ancestor of the early hominids and the chimpanzee lineage was skeletally more similar to gorillas and chimps and less like the early hominid bipeds .
    This would mean a long narrow pelvis precluding twisting at the waist and little or no ability to generate hip thrust .

    Now lets say the eureka moment in the clip happened to a pre hominid individual with a pelvis similar to later bipeds such as Lucy . A skeletal structure such as this with a broader and shorter pelvis and more anteriorly placed hip joints would be capable of bipedal stance, hip thrust ,waist rotation and hence be able to transfer far more kinetic energy from the whole body into a weapon such as the bone club shown in the clip .
    So the hero of the clip might be able to win a fight with a single blow but only if he was well on the way to becoming a bipedal hominid .

    I guess what I am saying is this becoming bipedal means that tools can be used far more effectively since the whole body of an individual can contribute energy . (Like a man swinging a baseball bat )

    Any thoughts ?
  3. scotfoot

    scotfoot Well-Known Member

    Further to above ,the gains in kinetic energy development to a tool, such as a club or held rock ,that are possible for a biped are not possible for an animal such as a chimpanzee .
    It is also likely that the physical possibilities of bipedalism drove neurological advancement since with increased choice more thought is called for .

  4. scotfoot

    scotfoot Well-Known Member

    So is there any consensus between the scientists in the various fields of science involved in studying evolution on the driving forces behind the development of bipedalism in hominids that eventually led to homo sapiens ?

    Well my take on it , for what that is worth , is as follows -

    The introduction of “biological clock” studies has now puts the split between the lines leading to chimpanzees (pan ) and us (homo) as happening between 10-7 million years ago . It has to be said that some confusion exists over the speed at which this clock ticks ,but lets go with that figure .
    So how did our ancestors split away from the lineage of the genus pan and how did bipealism develop ?

    Some authorities think that bipedalism developed among a subgroup of great apes involved in brachiation in forest trees with our early ancestors having a gibbon like phenotype ( note they do not say we descended from gibbons but that later more advanced apes became gibbon like through convergent evolution ).

    A large amount of work has been carried out on the anatomy of gibbons and the biomechanics of gibbon movement and it does seem plausible that our ancestors developed similar bodies which encouraged bipedal locomotion .
    But if such a creature leaves the trees and becomes more terrestrial what evolutionary factors continue to select for bipedalism .
    Many ideas have been forwarded for bipedalism and some are listed here -

    1 Bipedalism frees up the hands for tool use (Darwin )

    2 Hands freed up for males to take collected food back to a chosen location to feed a female and their offspring

    3 Seeing over tall grass the better to see predators

    4 More energy efficient locomotion

    5 Radiation avoidance - a upright stance might reduce heating of the brain


    When considering the first of these proposals ,that bipedalism frees up the hands for tool and weapon use there seems to be a tendency among those discussing the subject to point out that the use of stone tools started only about 2.5 million years ago and that only stick use by early upright hominids might be a possibility . Thereafter in such discussions tool use ( sticks) seems to be rejected in favour of some of the other alternative suggestions for bipedalism .

    However I would argue that a gibbon like ape armed with a sick is a totally different proposition than a a gibbon like creature without a stick .

    With its bipedal agility and large opposable thumb , a slightly more neurologically advanced gibbon like ape would be able to take a longish stick of suitable weight and , by incapacitating previously unapproachable prey species with the stick, begin to occupy an ecological niche not open to the other great apes .

    Such new prey species might include large arachnids ,reptiles and even small mammals .

    For example animals such as large spiders and scorpions ,which adopt a static , threatening posture when they themselves feel threatened ,would cease to be food items too hard to tackle and instead become easy to kill with a couple of whacks with a stick .

    Its also worth noting that in some parts of India urban rats are still hunted with a simple stick showing how effective this method can be .

    Even poisonous snakes ,normally a complete no go for a 10kg ape might be on the menu .

    So in summary then early hominids might have evolved a gibbon like phenotype through brachiation and then progressively moved to the ground there hunting with a stick gave them a great advantage over other animals and which allowed bipdalism to continue to be selected for .

    Any thoughts ?

  5. Rob Kidd

    Rob Kidd Well-Known Member

    Each time I make a comment on this arena vis: hominid evolution, I get a bite taken out of me. However, you seem to be genuinely interested. Thus I will attempt a reply. First, lose all thought of Kubrick. Now think adaptations and genetics. Think the Miocene, and the Red Sea spread. All spread starts from a triple junction (imagine pushing your finger through an orange peel), oceanic crust (tholeiitic basalt) is now pushed out at all three of the triples. Clearly this cannot continue - simple geometry tells us that - only two of the three can continue. Now, go to your school boy atlas, and look at the Red Sea; look at The Red Sea itself; look at The Gulf of Aden - and note the spread over the last 6-10 million years. Now note the East African Rift Valley - this is the failed arm of The Red Sea Spread. Fail it did, but it sure as hell changed the climate in East and Southern Africa! It got hotter and drier. Here is your experiment for the day: take your thermometer outside and measure the temperature at the ground level, and again at about 1.5 metres above that. Yes - about 5' cooler. Two things especially characterise hominid evolution: 1) encephalisation (sort of cerebralisation, as that was the only serious change), and 2) the bipedal habit. The process of cerebralisation came at a price: the brain was now in serious danger of overheating. Standing upright was the obvious answer. However, we are now in danger of a tautological argument - did the bipedal habit allow brain, or visa versa? To clever for me, that is for sure.

    The evolution of the Hominoid foot has been my life's work - but it cannot be studied outside the the rest of the body. Maybe this is someway to the questions you ask. But take my advice - leave popular science at the door

    Cheers, Rob,
  6. scotfoot

    scotfoot Well-Known Member

    Hi Rob
    Many thanks for taking the time to reply to my posts .

    Given your qualifications and occupation I should imagine you have forgotten more about the evolution of the human foot than I will ever know .
    That said you must be aware that the radiation avoidance theory as a primary driving force behind the development of bipedalism is very much a minority view among
    paleoanthropologists . I have included the abstract of a paper from a 1994 below .

    Article: Physiology, thermoregulation and bipedalism
    George Chaplin ? Nina G. Jablonski ? N.Timothy Cable 1994

    It has long been recognized that the bipedal posture reduces the surface area of the body exposed to the sun. In recent years, a theory has been developed by Wheeler that bipedalism evolved in the ancestor of the Hominidae in order to help relieve thermal stress on the animals in open equatorial environments. Bipedalism was said to afford a distinct adaptive advantage over quadrupedalism by permitting hominids to remain active in the open throughout the day. The heat load of the hypothetical hominid comprises the external environment as modelled by Wheeler and the animal's internal environment (i.e., the internal heat generated by its metabolic and locomotor activities, and its evaporative and respirative cooling capacities). When these factors are integrated in the calculation of the animal's thermal budget, the putative advantage of the bipedal over the quadrupedal posture is considerably reduced. The simulations conducted in this study suggest that the increased time afforded to early hominids in the open by bipedalism was relatively short and, therefore, of little or no adaptive significance. These results suggest that thermoregulatory considerations cannot be implicated as a first cause in the evolution of bipedalism in the hominid ancestor.

    All this said many of the mechanisms suggested for the development of and selection for bipedalism may play roles at varying stages of human evolution with radiation reduction being a factor in such activities as persistence hunting and long distance travel as homoerectus gave rise to homosapiens .

    It still seems to me that the mechanisms proposed in my last post are the most plausible explanation for the initial development of a hominid more comfortable in a bipedal stance than as a quadruped .

    However, I am not married to the ideas I have outlined ( which are generally based on the ideas of others ) and would welcome any direct criticism .


    Gerrard Farrell

  7. Rob Kidd

    Rob Kidd Well-Known Member

    This cracks me up. Nina was on the staff at The University of Western Australia while I was a PhD student. together with the late Len Freedman, I credit them with teaching me to read and write. George Chaplin is Nina's 'usband She is a US lass - State of New York somewhere, George is a Pom, with a Cockney accent. Nina went on from the fossil world of "Theropithecus: The Rise and Fall of a Primate Genus" which was in its day her opus, to become very, and I mean VERY famous in skin pigment and looking at how colour is aligned to latitude. She is now Prof of Anthro at Penn State, a rampant evolutionist and a devout Buddist. I think the world of her, Rob
  8. scotfoot

    scotfoot Well-Known Member

    All things considered it may be best to keep the stuff in your first post about the evolution of bipedalism and radiation minimalisation just between you and I . That's probably your best chance of avoiding a metaphorical clip round the ear from your former mentor , Professor Nina Jablonski .
    Mum's the word .

  9. Rob Kidd

    Rob Kidd Well-Known Member

    Well Gerry, you may think so, I do not. The way to tell the world is to tell it, but via recognised refereed journals. As a matter of interest, I am also a Scot - but Dad left when I was a child. My GGPa was Hugh McPherson, Master Mariner, Faslane. He was double qualified, in sail and steam. If something is true, then it is true, and then it needs talking about. Any critics of evolution - let them bring forward a (proper) paper in a (proper) scientific journal, I will then look at it more seriously. Rob.
  10. scotfoot

    scotfoot Well-Known Member

    No offence meant Rob . The post was meant as humour and I thought the wording would raise a smile .

  11. Rob Kidd

    Rob Kidd Well-Known Member

    No worries, Gerry
  12. scotfoot

    scotfoot Well-Known Member

    Following on from the posts above perhaps the chimpanzee -human last common ancestor gave rise to a gibbon like phenotype which eventually became terrestrial once more leading to the extant Homo (human) genera of homini . Us

    If this happened then the foot of our brachiating ancestors would need to evolve from a grasping structure to something that functions in a quite different way since in my opinion human toes cannot be said to grasp the ground but act to allow traction by remaining straight other than flexing around the metatasophalangeal joints.

    Provided at the end of this post is a link to a fossil footprint made about 1.5 million years ago ,possibly by Homo Erectus . You can see that there is a mound of material left between imprints of the toes and the ball of the foot . To me this clearly indicates that even on slippery surfaces the toes of this almost human foot , do not curl but stay straight to maintain traction . The toes do not grasp the ground they remain as straight as possible and presumably hinge around the metatarsophalangeal joints . If the toes curled then the material between the toes and ball of the foot would be extruded giving less grip not more .

    Any thoughts



    Earliest human footprints found in Kenya | World news ...
    Footprints found on a sandy plain in eastern Africa have been hailed by scientists as the earliest evidence of modern upright walking. The footprints, dated to ...
  13. efuller

    efuller MVP

    This really runs into the problem of extrapolating to an entire ancient population from a single foot print or a single fossil. Looking around at the variation of feet in the current population there are a lot of outliers in terms of morphology and in terms of the foot functions. There are feet alive today that will have significant claw toes that could leave a pile of mud in the sulcus after a step and there are feet that could have the toes remain straight while stepping in mud and not leave a pile under the sulcus. When you are looking at single footprint, how do you know you are not looking at an outlier?

    That said, todays relatively short foot phalanges make grasping really difficult compared to the relatively long phalanges of the hand. That observation would make a better case for foot evolution where the hind limbs are used to walk and the forelimbs are used for manipulating objects. I have no idea if apes or monkeys have longer hind limb phalanges.

    Another area to look at is the difference in long flexors of the hand versus the foot. The long flexors and extensors of the foot make it really difficult to control individual toes because of how the muscles split and attach on multiple toes. If apes have better individual control of hindfoot phalanges, then that would be a case for evolution or devolution. More fit for walking, less fit for climbing trees.

  14. scotfoot

    scotfoot Well-Known Member

    OK .Lets say this is the foot print of an outlier of the extinct homo erectus . Lets move on 1.5 million years or so and look at the feet of a habitually unshod human .
    Lets say the person is running over yielding wet soil .
    Under these circumstances how does the foot gain sufficient grip so as to avoid a slip and a fall as the body applies forces through the foot into the ground .

    To simplify the question lets look at the area of the foot in contact with the ground during late stance as the COM moves over the standing foot and the heal and midfoot have left the ground . Now the area of contact with the substrate consists of the ball of the foot and the toes . Almost like the print of a digitigrade animal .

    At this stage the forces being transferred to the ground through the foot can be divided into vertical and horizontal components . What stops the foot from slipping backwards as horizontal forces are applied ?

    Whether the toes are straight or clawed as the foot landed ,in a close to toe of position is there active curling of the toes or do they remain as straight as possible .?

  15. efuller

    efuller MVP

    Friction. The coefficient of friction will be higher with more surface area in contact with the ground.

    It varies across people. Are you asking what is ideal or are you asking what happens most of the time? It is a very interesting question to think about why some toes curl and others remain straight. I have some theories. I'm not very confident in those theories. Why do you ask if the toes remain straight? The area of contact with straight toes is not that much greater than with some curled toes.

  16. scotfoot

    scotfoot Well-Known Member


    Surely with regard to traction the interaction between the substrate and the standing foot is about more than just friction .After all, on a yielding soil imprints are created and within these imprints we find ridges and depressions .
    To me this indicates a gravity driven ,passive grip system in the forefoot and also helps to explain the vital role of toe nails in substrate /foot interaction .

    The grip system I have in mind will only work optimally if the toes remain straight as the heel of the standing foot lifts from the ground leaving only the ball of the foot and the toes in contact with the ground .

    So why do some toes curl during locomotion ?

    In brief, in my opinion, the toes will adopt the position of maximum mechanical advantage, for given strength levels in the musculature, when called upon to bare load /produce force during standing or locomotion .

    In groups with well developed foot musculature I would predict that the toes will generally remain straight when called upon to perform work. However ,when a foot with weak musculature is called upon to perform work the toes will collapse into hammer or claw toe type positions since it is only these shortened positions that weak toes can perform their roles during gait .

    In summary, weakened toes will collapse into the position of maximum mechanical advantage for given strength levels when challenged with load .

    In fact I believe this may true of the entire foot with people suffering from pathologically driven atrophy of the intrinsic musculature developing shortened feet with high arches and proximally/dorsally migrated metatarsal /phalangeal joints .

    It may be worth noting that this collapsing/shortening of foot structure will ,in my opinion , be most obvious in feet which become weakened but which continue to be subjected to normal loads . If and individual with severely weakened feet subconsciously reduces the load to which the foot is subjected by a change in gait strategy ,for example the adoption of a high stepping gait that avoids toe off ,then perhaps changes in toe/foot morphology are avoided .

  17. efuller

    efuller MVP

    Most of the time we are on solid ground. So, for reproductive fitness we should be looking at what happens on solid ground. When I run and have to step into mud, I make more of a conscious effort to minimize slipping which is running in such a way to minimize a-p horizontal forces. For a few steps your momentum will carry you forward and you don't have to push with the foot.

    Yes the plantar fascia is a passive grip system that will tend to cause a plantar flexion moment at the mpj's. I doubt that human toenails are involved in gripping and traction. The few times that the toes plantar flex that much at the distal phalanx, you usually see deformed nails and pain.

    I don't see why curled toes couldn't grip as well as straight toes. Not there is that much need for gripping.

    Mechanical advantage to do what? Plantar flexion of the toes around toe off to provide push? This could be part of ankle joint power in providing muscular effort to swing the leg forward. However, Winter has shown that there is quite a bit of between and within individual variation in the amount of ankle joint power in walking. Sometimes we pull the swing leg forward with the hip muscles rather than push the swing leg forward with ankle, and toe, plantar flexors. We have many different ways of walking. We don't always need to get maximum mechanical advantage.

    My theory on claw toes is that there is greater than normal use of flexor digitorum longus. When seated, you can contract this muscle and see that it will tend to cause claw toes or hammer toes. One reason that someone may use there flexor digitorum longus more than average is that FDL is the second best supinator of the STJ behind the posterior tibial muscle. If the PT muscle cannot provide enough supination moment, the person may choose to recruit their FDL muscle add more supination moment.

    A well developed flexor digitorum longus is more likely the cause of claw toes. The toes will not just collapse into clawing. Something has push or pull them into clawing.

    Ground reaction force and body weight will tend to flatten the arch. Weak muscles wouldn't be able to fight gravity and ground reaction force as well as strong muscles. You would expect to see a flatter arch in the presence of week foot musculature. (The exception is the Achilles tendon, which when it contracts will tend to flatten the arch.)

    The reason that you might see a higher arch with weak muscles is that the muscles of the arch have atrophied. If you had week lumbricles and normally strong FDL you could expect hammertoes and claw toes to develop. When the FDL contracts in will exert a plantarflexion moment at the distal inter phalangeal joint. That will cause an increase in ground reaction force at the tip of the toe. That ground reaction force will tend to dorsiflex the metatarsal phalangeal joint. If the lumbricles cannot prevent the dorsiflexion you will get the claw toes. I've looked at some cadavers with claw toes and the lumbricles do loose there mechanical advantage to platnar flex the MPJ when the MPJ is dorsiflexed.

    I agree. I think that this the loss of "the spring in your step" that you see in older individuals. People choose to use a little more hip pull and less ankle push. I think they do this to avoid foot pain.

  18. scotfoot

    scotfoot Well-Known Member

    The passive grip system I have in mind does not involve the plantar fascia or contact of the toe nails with the substrate .

    As regards reproductive fitness if the two of us were hunting buddies some 50 000 years ago and a pack of 600 kg long fanged carnivores was chasing us I am afraid I would a bit relieved to see you slow down and coast at the muddy bits . I would keep going hell for leather .

    When the heel leaves the ground during running you have only the ball of the foot and the toes in contact with the ground . On yielding substrates such as the savanna in the wet season the material between the toes and in the sulcus provides grip . Curling the toes extrudes this material and breaks the grip .

    Based on personal experience I believe that if a normally shod healthy individual stands barefoot on one foot and then leans forwards the toes will collapse into a hammer toe like configuration . However if the intrinsics are strengthened and the sequence repeated the toes remain straight providing a longer more effective lever . Hence "position of maximum mechanical advantage for given strength levels .

    Based on the above in my opinion strong extrinsics do not cause toe clawing or hammer toes but rather weak intrinsic coupled with demand in late stance does .

    I may be wrong but my understanding was that the bony arch of the foot becomes more arched in some conditions which cause neuropathy and intrinsic atrophy .

  19. efuller

    efuller MVP

    From your earlier quote, you can see why I thought that your grip system involved the nails. If it doesn't involve the plantar fascia what does it involve beyond friction? We may be saying the same thing from different directions. Toe plantar flexion moment will press the toes into the ground which will increase the surface area of contact with the ground and that will increase the frictional surface area.

    The reason that I would slow down would be to avoid slipping and falling and becoming easy prey. If you try and push off, and there is no friction, your leg will go backward and you won't go forward. Probably just better to avoid the muddy bits.

    The material between the toes only provides grip if it is firmly affixed to the underlying surface. Mud, for example will shear quite easily from the rest of the underlying mud and your leg will go backwards with some mud stuck in your sulcus.

    When you stand on one foot, or both feet, and lean forward you will fall forward if you don't shift the center of pressure of ground reactive force forward. If you lean far enough forward you will need to shift force out on to your toes. That does happen somewhat passively with the plantar fascia, but it will happen actively with use of the toe flexors. Long flexor tension when the foot is on the ground will cause hammertoe configuration to occur for the reason I stated in an earlier post. So, in your leaning forward example, I would bet the long flexors are what are causing the hammertoe appearance.

    You mentioned weak intrinsics causing hammertoes. So, what causes the push or pull that causes the toes to curl if is not the extrinsic? The absence of pull is not going to cause curling. I could see it being possible that the lumbricles being strong enough to create prevent dorsiflexion at the MPJ. Yes, I agree that straight rigid toes could allow you to lean further forward than curled toes.

    They make the arch appear higher because there is less muscle mass under the bones. The physics of the situation have the intrinsic muscles raising the arch. If they are weak they cannot raise it as much and you would expect no change, or a lower arch, in the shape of the bones in response to gravity and ground reaction force

  20. scotfoot

    scotfoot Well-Known Member

    Yes sloppy of me .
    The plantar fascia does of course play a role in pressing the toes into the ground and in so doing contributes to the grip systen of the humam foot as I see it . Its just that it does not act to press the toe nails into the substrate to any significant effect .
    However , as I said the toe nails are vital to the way our feet interact with the ground to produce traction ..Just not in the way you mentioned .

    Re avoiding the muddy bits when being chased for your life by a group of hungry carnivors I feel that feet that don't work in the wet would be quickly selected against in evolutionary terms .

    I mean come on Eric . Is it just our feet that don't work in the wet or would the rainy season in the Rift Valley reveal tens of thousands of Wildebeests falling over when trying to escape a lion hunt - conducted by a pride of lions which also can't keep their feet/paws .

    I don't know if you own a dog but if you look at the prints they leave behind when running at full tilt over soft ground you will find neatly formed paw prints with no tearing up of the substrate.

    I think we agree that in the absence of strong intrinsic musculature the toes will be supported by the extrinsics and pulled into a hammer /claw toe configuration when load is applied .

    I know exactly what you mean about an intrinsic minus foot only looking to have a high arch due to muscle atrophy but as far as I can ascertain the actual bony arch itself is raised by the tensioning of the plantar fascia .

  21. efuller

    efuller MVP

    In what way do the toenails interact with the ground to increase traction?

    Most carnivores are faster than a running human. It would be more adaptive to not do stupid things like hang out where the carnivores could get you. Man's survival is not dependent on his running speed. It is probably more dependent on being smart. So, if you are smart you can still survive with good enough feet. Looking around at our present population, there are plenty of people that have children with sub optimal feet.

    If there was any push off, there would be tearing of the substrate and show an evidence of slide in the foot print. Maybe your dog is just using momentum to move along and has learned not try and push off in the mud.

    When there is atrophy of the intrinsic muscles, the plantar fascia remains unchanged. There is no reason for the arch to be higher because of the plantar fascia.

  22. scotfoot

    scotfoot Well-Known Member

    A number of studies have looked into conditions which cause neuropathy and atrophy of the intrinsic foot muscles .
    It has been found that atrophy does not always lead to deformity and I feel that our conversation may have kicked up a possible explanation for this .--

    That is ,in the absence of strong intrinsic musculature the toes will be supported by the extrinsics and pulled into a hammer /claw toe configuration when load is applied during locomotion .In situations were sufferers adopt new gait strategies such as a high stepping less load may be applied to the toes and deformity may be avoided .

    This might be of some importance and perhaps we should give each other a pat on the back .


    In sports such as American football or rugby the competitors wear boots with cleats or studs to improve grip and traction. Not shoes with smooth soles made from materials with similar frictional characteristics to keratinised skin . Clearly grip is important when humans compete physically and this would be selected for in the barefoot condition .

    In what way do I think the toenails interact with the ground to increase traction?

    Eric , I thought you would never ask .

    Since this thread contains a number of topics I intend to answer this question in a new thread "What are toe nails for ".


    Ps What did you think of my stick based early hominid hunting technique ? In true tabloid tradition I have called it PAW . Short for prod and whack . The prod to convince an animal such as a large spider that it can't escape and thus cause it to adopt a static threatening posture and the whack to dispatch it.

    Gerrard Farrell

  23. davidh

    davidh Podiatry Arena Veteran

    I won't jump in quite yet, but I'm watching with interest :morning:
  24. scotfoot

    scotfoot Well-Known Member

    Given that you are an expert witness I should imagine that you are uniquely qualified to comment on footprints and the way they are formed . Do you believe that toenails contribute to grip and traction and if so how .

    Also I would be interested to know whether the bony arch of the foot becomes more arched in some disease related cases of severe intrinsic muscle atrophy .

    Also with regard to PAW ,which may simply be fluff , I wondered what people were thinking . There may be some evidence for it in extant species .

    I greatly look forward hearing from you .

  25. davidh

    davidh Podiatry Arena Veteran

    Hi Gerry,

    I'm not a forensic expert, and know little about footprints. Gait, a little more.
    Plenty of conditions affect the bones and structure of the foot, changing the position and therefore action of certain muscles.

    Toenails can only contribute to grip on undulating and/or soft ground, and only then (unless they very long :D ) after mid stance.


  26. scotfoot

    scotfoot Well-Known Member

    Hi David
    I am headed in three general directions and so intended to start a couple of new threads when time allows .


    1 Early hominid tool use and possible evidence for this in neurological adaptations seen in extant species . For example the stimulus trigger for some species of spitting cobras .

    2 The pathogenesis of foot deformity in people suffering from diabetes .

    3 Clarification of how the unshod foot interacts with a substrate to provide grip and traction .

    The forefoot is an area packed with structure but I can find almost nothing in the literature about the mechanisms involved in helping to prevent the foot slipping during locomotion .

    Since the foot is were the rubber meets the road this is a little surprising .

  27. scotfoot

    scotfoot Well-Known Member


    Would you agree that toes have a pedunculated shape and that when the toes are pressed into the ground the nail ( which is attached via the nail bed and associated ligaments to the periostium of the underlying phalanx) helps to cause lateral rather than vertical displacement of the toe pulp and hence a more even pressure distribution within the pulp and across the area of toe contact with the ground ?

    Would you also agree that its easier to pull a knife through cold butter than a spoon ?

  28. davidh

    davidh Podiatry Arena Veteran

    Anyone who didn't believe in evolution need only look at this thread and see how it's evolved :D . You do skip about Gerry, if you don't mind me saying so.

    As to the first - nice theory - lets see some working out. I did a joint paper for The Foot some years ago, about how involuted nails may not always be the product of tight footwear, and may, in fact, be the nail plate following the shape of the terminal phalanx.
    Cadaver terminal phalanges were used.
    It was an adaptation of a pilot study carried out as part of an final year pod study.
    The other author was D McMahon.
    If you are going to research your first postulate you many want to dig it out.

    As to the second - there is no research needed.



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