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Should runners alternate their running shoes .

Discussion in 'Biomechanics, Sports and Foot orthoses' started by scotfoot, Dec 13, 2019.

  1. scotfoot

    scotfoot Well-Known Member

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    Recently there seems to have been a trend ,on running advice sites and the like ,towards recommending that runners alternate their shoes instead of just using the same type of shoe all the time . The idea seems to be that this strategy will help avoid injury ,but is it true ?
  2. scotfoot

    scotfoot Well-Known Member

    Where I am coming from with this is roughly as follows .
    The foot can be viewed as an organ involved with balance , propulsion ,proprioception and venous return . With regard to proprioception and whole body coordination , how can the foot be relied upon to its job , in a proprioceptive sense ,when ever changing footwear keeps moving the goal posts .
    To use an analogy , how good would a professional golfer play if every time he went out onto the course he was given a radically different set of golf clubs and an untried make of ball .
    We know from the work of Lieberman and Davis that cushioned heels cause greater impact transients or ,if you like ,that footwear can fool the foot .
    Wouldn't it be better to stick with one type of shoe and let your feet/body accommodate to this ? If you want to cross train then fine , swim or cycle .
  3. Craig Payne

    Craig Payne Moderator

    Two studies show that more shoes a runner has in the rotation the less risk for injury (sorry, holidaying, so no time to look up the refs - do that later)
  4. Dr Rich Blake

    Dr Rich Blake Active Member

    I have always used shoe rotations as a way of cross training and injury prevention. The minimalist shoes forced the issue when running had to wear this type of shoe. I would compromise by letting them use when injured two days a week in their minimal shoes and two days a week in the traditional shoes. Of course, the biomechanics of each shoe had to be analyzed and the athlete had to know the rules of the game. Then, the fun began with the maximalist shoes like Hoka One One. Now, my regular athletes train in both Hokas, or other zero drop shoes, and traditional shoes. I think it is very helpful to them. They are also not so brain dead with running through injuries like they used to and only make themselves worse. This not a new idea. In high school, I had my trainors and my racing flats and we ran barefoot on the beach up to 16 miles once a week. Rich
  5. Like Rich Blake also noted, the idea that runners should rotate running shoes from day to day is definitely not a new idea. When I was running cross-country and track for the UC Davis Aggies from 1975-1979, most of my long-distance teammates had at least two if not three pairs of running shoes. When I was running marathons in the late 1970s and early 1980s, I had three pairs of running shoes I would rotate through on a daily basis. Serious distance runner understood the concept, even 40 years ago, that different running shoe constructions would tend to stress different parts of our lower extremities differently so that not running in the same running shoe every day would likely prevent injury. I don't understand why this concept is just now being viewed as being a new concept since it has been around for at least four decades.
  6. scotfoot

    scotfoot Well-Known Member

    Simon ,
    I hoped the above would be a link to a paper but it does not seem to be working . It just says this

    <Message>Request has expired</Message>
  7. W
    works for me. Paper is: Can parallel use of different running shoes decrease running related injury risk? Google should find that.
  8. scotfoot

    scotfoot Well-Known Member

    I can't access the full paper as yet but it looks like the two study groups were self selecting . One group (two pairs ) probably more clued up than the other (single pair) . If the study was between two groups that had already developed different mindsets towards injury , then it's not much of a study .

    I do understand the idea of different types of running shoes stressing the body a little differently and so perhaps helping to guard against overuse injury , but at present I am viewing things through the prism of proprioception and the possible confusion in the CNS if shoes are always changing .
  9. The
    The CNS doesn’t get confused!
  10. scotfoot

    scotfoot Well-Known Member

    People (the brain ) don't get confused ?
  11. The CNS doesn’t get confused by running in different shoes. Rather the CNS modulates leg stiffness to maintain the centre of mass displacement pathway to be within as near to as possible an optimum to maintain metabolic cost to minimum in the presence of different shoes and terrains. You are alluding to the Robbins-Gouw hypothesis, which is just that and not well supported by Science
  12. Nope, prospective study which in my mind had pretty strong methodology, analysis and interpretation of data. Full text here:
  13. scotfoot

    scotfoot Well-Known Member

    Thanks .
    Having read the paper it still seems to me that the alternating group probably has a greater injury awareness than the non alternating group or they would not alternate . This may have introduce a variable that has not been adjusted for .
    The study has two groups, one where shoes are alternated and one where they are not , but you could also say you have an injury savvy group and a non savvy group . Different mindsets or they would not be behaving differently from choice .
  14. Nope, you had one group of runners. Within that group some rotated their shoes, while others did not: those that didn’t rotate their shoes got injured more than those that did. There is absolutely no evidence within that paper that those who got injured less had “greater injury awareness”. The CNS was not “confused” in those runners that chose to rotate their shoes. That is what the evidence tells us, although you’d like it to fit your agenda, it does not. Please show me the evidence that rotating running shoes between running activities “confuses the CNS” and has a detrimental effect... bet you can’t.
    Last edited: Dec 14, 2019
  15. scotfoot

    scotfoot Well-Known Member

    On this particular occasion and in this thread I don't have an agenda or even any firm views . I am just digging about trying to understand how shoes impact the sensory capacities of the foot .
    If alternating shoes reduces injury rates then that's good . However I don't like the particular study under discussion for the reasons given .
    Self selection into the alternating group ,within the larger study group , demonstrates a willingness to try and avoid injury that is not demonstrated by the non alternating group . As previous contributors to the thread have said ,the perceived wisdom in running communitoes has , for a long time , been that shoe alternation helps prevent injuries . If that is the case why would you not .
    It seems as likely to me as not, that ,on average, shoe alternators might take more care to avoid injury than non alternators . For example they might do a warm down .
    In the study the alternators were found to be different than the non alternators in a variety of ways . The study would have been more persuasive if it had looked at other factors such as warm ups warm downs and general run preparation all of which take time and effort but which might impact injuries .
  16. But you are guessing because the study didn’t measure injury awareness, nor whether participants performed “warm down” activities, which BTW lack empirical evidence to suggest they reduce injury risk anyway:

    I could guess that those with the greatest injury awareness should have been the sub-group who had experienced a previous running related injury, yet this group got injured more. I might make the case that those who ran in more than one type of shoe were in jobs that earned higher salaries than those who ran in the same shoe; those that ran in one type of shoe might have all been vegan, Piscean and left handed, but I’m guessing that too. What we do know is that the risk of running related injury was lower in the group that chose to run in different shoes across their training. This doesn’t sound to me like a group of runners with “confused CNS”, but I’m guessing because the study didn’t measure that either.

    At the outset of this thread you asked if the process of shoe rotation can help prevent injury, the best evidence we have to date shows that when runners choose to rotate shoes their injury risk is lower. We don’t know if that is a direct mechanical effect or a psycho-social effect or a combination of both, but choosing to rotate shoes seems to reduce injury risk.

    Now explain to me why you believe that running in shoes “confuses the CNS” and how the shoes do that...
    Last edited: Dec 15, 2019
  17. scotfoot

    scotfoot Well-Known Member

    The researchers would have had a better study if they had looked more closely at injury awareness since shoe rotation , a common injury prevention strategy , and injuries , is what the study is primarily about .

    Agreed .

    Actually , injury prevention strategy apart , the most obvious reason I can think of for rotating shoes between runs is to let wet shoes dry out .

    But we are talking different pairs here . If I walked into a running shoe shop , the sales person might be able persuade me to buy two identical pairs of shoes since it rains a lot in Glasgow . However , the only way that I could be persuaded to buy two different designs , would be if injury prevention were explained to me . Otherwise , how could the sales person say " this is the pair for you because of its design features " , and then say " but this different design is also the pair for you " .

    I should probably point out here that I never go distance running . 100 m tops .
  18. efuller

    efuller MVP

    People run differently on different running surfaces. There was a study that showed that people (the CNS) adapted in one step to the different surface.
  19. scotfoot

    scotfoot Well-Known Member

    What I am saying is that , during gait , footwear may detrimentally alter proprioceptive feedback from the foot and so cause the body to function in a way which could lead to injury .

    For example non prescriptive medial arch supports might affect efferent info , generated by organs located in the plantar fascia and designed to detect force, leading to higher impact transients .

    Also footwear may reduce the foots ability to detect and relay information
    about the torque generated by ground reaction forces in the foot and more distal joints of the lower limb.
  20. scotfoot

    scotfoot Well-Known Member

    With regard to the above and the work of Lieberman and Davis , it strikes me that the non prescriptive use of medial arch supports in modern running shoes is as likely , if not more likely ,to be the cause of harmful impact transients , as cushioning in the heel area .

    This raises the interest prospect that you can have as much cushioning as you like in a shoe , so long as you don't have a non prescriptive medial arch support . Thus Hoka shoes may be no more likely to produce high impact transients than less cushioned shoes if the arch support effects are similar .

    The question of toque during gait and proprioception is more complex because socks are usually involved .
  21. Which studies by Lieberman and Davis are you referring to?

    when you say “impact transient” are you talking about a heel strike transient?

    Please explain how footwear has a detrimental impact on proprioception. How do shoes stop the nervous system from detecting and relaying information?
    Last edited: Dec 19, 2019
  22. scotfoot

    scotfoot Well-Known Member

    More a letter than a study , here -

    Harvard Barefoot Running

    www.barefootrunning.fas.harvard.edu › Nature2010_FootStrikePatternsan...
    It seems feasible to me that the plantar fascia and ligaments of the foot , can relay to the CNS , the degree of force to which they are being subjected during gait . Add in a medial arch support and you reduce these forces during midstance ,which as I understand it is when maximum ground reaction forces are experienced , which might lead to a CNS underestimation of the forces being experienced by other parts of the lower limb .

    During late stance the forefoot experiences torque . In an unshod foot the deep transverse ligament is put under strain in a manner to which it is not in the shod foot and so accurate input may be lost to the CNS as to the torque being experienced in more proximal joints . In terms of toe separation during late stance , footwear can be said to be acting as a splint .

    I would like to see a project which looked at heel impact transients where the only variable was the presence or absence of medial arch supports in otherwise well cushioned shoes .

    Note that I am not a fan of running or even walking barefoot on concrete since the foots internal cushioning , the fat pads , have not evolved for this purpose .

    "Impact transient " yes " heel strike transient"
    Last edited: Dec 19, 2019
  23. Have you read the Lieberman and Davis studies? Here’s Craig’s review of it:

    why would an arch support impact on the CNS ability to detect load? As I see it running shoes, different surfaces and arch supports all change the input, but the CNS is not confused in anyway, as you have suggested, merely the CNS responds accordingly to the input just as it does when walking or running barefoot. Having read lots of work in this field, I have come across nothing to convince me that the CNS is somehow tricked by wearing a shoe.

    There’s a reason it’s called a heel strike transient: do we see a heel strike transient when running barefoot and heel striking?
  24. scotfoot

    scotfoot Well-Known Member

    Because it offloads the tissues in which the proproceptive organs are found .

    Good question .What's the answer ?

    Any views on this bit ?
  25. Off-loading- so the CNS responds appropriately to the new load. Viz. it’s not confused.

    seen plenty of barefooted heel strike runners in nearly 30 years of clinic- it’s the strike pattern not the shoes that create the heel strike transient- guess the clue is in the name.

    To save going over old ground, it should probably be worth your while to review the barefoot running threads and leg stiffness threads here.
    Last edited: Dec 19, 2019
  26. scotfoot

    scotfoot Well-Known Member

    If you offload a tissue with nerve specialized nerve endings designed to detect stress (the plantar fascia ) and load instead a tissue which does not readily detect the forces you are placing upon it ( compressive loading of the muscle underlying the fascia ) then the CNS says less load even although its the same as before .
  27. Except you’ve still got loads on other receptors in lots of different tissues for example skin. I’m not even convinced that compression on a muscle belly wouldn’t evoke a response from the GTO’s in the tendons of those muscles. Moreover, does loading the fascia with an arch support prevent it from detecting load? Indeed if the arch support is offloading the fascia, then the same load can’t be on the fascia and the receptors in the tissues that the load has been shifted to, will register the increased load on them. We are not going to agree on this, so I’ll wish you a merry Christmas and leave it there.
  28. I never accepted the idea that the central nervous system (CNS) somehow became "confused" or "didn't respond appropriately" when running in shoes with cushioned soles. The hypothesis put forward by Robbins and Gauw in 1991 seemed to me, to be quite far-fetched and not consistent with science. https://pdfs.semanticscholar.org/5689/dc03522ff19dabad98209e74b17ee9d8939c.pdf

    In fact, the ideas of Robbins and Gauw, instead of being supported by research, has not been supported. Instead, research shows that the human CNS in experienced runners is quite able to respond within one step to alterations in the stiffness of the surface being run on. And, when I say surface, I mean the combination of shoe midsole stiffness and the surface the individual is running over.

    Research from a few years ago clearly shows that anesthetizing the plantar foot cutaneous receptors does not influence barefoot running kinematics or kinetics, so these superficial plantar receptors are not likely that important in running biomechanics. Even if these plantar receptors were "confused", I doubt that they would have much impact on running biomechanics in the first place.


    As Simon mentioned earlier, regardless of whether one set of afferent receptors in the foot are affected or not by a cushioned midsole, there are plenty of other afferent receptors within the joint capsules and tendons of the lower extremity, and the inner ears and eyes, to name a few, which have can contribute to the afferent input into the CNS. Then, with this wide range and number of afferent inputs to choose from and process, the CNS will then be able to determine the efferent signals most appropriate produce the optimum temporal patterns and contractile strength for each of the lower extremity muscles during each running step.

    Furthermore, the recent advent of more cushioned shoes over the past decade (Hoka One One being the company that started the trend, and with the Nike Vaporfly leading the field as of the present), has not shown an increase in injury rate in those runners using these highly-cushioned shoes. From my perspective as a clinician and runner, these observations further refutes the Robbins and Gauw hypothesis.

    Rather, the research so far indicates that the CNS of experienced runners has an excellent potential to adapt to all external conditions very quickly to produce the most economical running gait pattern for that runner. Therefore, please don't sell the CNS short for its ability to optimize gait patterns in runners, regardless of what shoe or surface the individual is running on. The CNS does not get "confused" by thick-soled, highly-cushioned running shoes. Instead, the CNS learns very quickly how to use these highly-compliant, resilient midsole foams to improve the metabolic efficiency of running gait.
  29. BEN-HUR

    BEN-HUR Well-Known Member

    Put another way: The CNS doesn't get "confused" in any HEALTHY individual. Quickly evident within the running/shoe context (the context of this thread mind you).

    Go for a road run with your chosen (habitual) running shoes; quickly remove them & see how quickly your foot strike & gait changes (yes, the CNS is at work - it's functioning as it was designed to do).

    Let's try to confuse the CNS: put on a specific type of shoe (so the mind knows you're putting on a shoe)... putting on a shoe however with minimal midsole cushioning for the first time… once again, see how quickly the foot strike & gait changes within a couple of strides (of what is 'normal' for the individual) with that specific shoe on (the CNS wasn't "confused" by the shoe - the CNS responded accordingly to ground reaction forces).

    I can recount the experience of an experienced runner (sub-4min miler) trying the Vibram Five Finger shoe for the first time (on a hard surface i.e. footpath). He had a preconceived notion that everything would be the same except that he would be running in a lighter less restrictive shoe (along with strengthening lower limb musculature). He was enthusiastic about the experience due to the surrounding hype at the time... his enthusiasm didn't last long (in fact, he initially was quite annoyed by the experience)... the preconceived notion (his mind) was that he would naturally run a per normal - he could not (hence the mind/thought process & shoe could have confused the CNS - they could not). I saw the foot strike & gait quickly change (within a few strides) due to the uncomfortable feedback he received via his CNS (i.e. discomfort) due to less cushioning present under his feet... however, the foot strike & gait quickly changed once he hit the grass (being softer/less stiff surface). I witnessed changes (& he felt them) from a very sensitive systematic CNS.

    The CNS quickly adapts (i.e. milliseconds - seconds) in any HEALTHY individual (one with a normal functioning nervous system). These very changes we see are evident that the CNS does not get "confused"... the confusion lies in the interpretation of what some are observing (sometimes bias to an underlying agenda). For some, that agenda may have stemmed from the barefoot running movement 10 - 15 years ago... or having their reasoning influenced by it. The "confusing the CNS" phrase/reasoning is (in my opinion) antiquated, pseudoscientific sound bites from that era in an attempt to demonise running shoes with mid sole cushioning properties - which was part of their agenda/reasoning (in favour of bare foot/minimalism - of which influenced by the observation of very conditioned Indians running likewise on habitually softer surfaces of the desert). It was (in my opinion) a "throw the baby out with the bathwater" attempt to scorn against the beneficial properties of having runners run in shoes (with cushioning properties) where many of us run on very hard & unforgiving surfaces (i.e. roads/asphalt/concrete/footpaths) of which we live (& what the majority of running races are held on).

    From memory, there was a research paper done (by Dr Jack Daniels) which somewhat relates to this topic i.e. running economy in relation to... barefoot, shod running, shoe weight, shoe & surface cushioning/stiffness properties. In short, the CNS was very sensitive in selecting the most economical (metabolic cost - muscle activity/oxygen consumption) balance for the above factors for optimal running performance. From memory, the results were repeatable & hence predictable - hence the CNS was not being "confused".

    The CNS doesn't get "confused" in the running shoe context... it adapts... it makes changes... sometimes these forced CNS changes (influencers) to the likes of foot strike, ankle, knee, pelvis patterns can have beneficial outcomes (i.e. extending/offsetting injury threshold)... sometimes not (i.e. shortening injury threshold) - there's a whole multi-page thread on that on this forum. There are a number of variables at play here... we just need to use our brains & (objective) CNS in being proactive to figure it out what is best for ourselves (& other individuals).
  30. scotfoot

    scotfoot Well-Known Member

    With regard to the foot , proprioception and footwear , does any one have any thoughts on the above quote , about torque , taken from earlier in the thread ?
  31. Gerrard:

    Let's first analyze your quote "During late stance the forefoot experiences torque . In an unshod foot the deep transverse ligament is put under strain in a manner to which it is not in the shod foot and so accurate input may be lost to the CNS as to the torque being experienced in more proximal joints . In terms of toe separation during late stance , footwear can be said to be acting as a splint ."

    1. During late stance the forefoot experiences torque. Yes, all the joints of the lower extremity are subjected to rotational forces (i.e. moments, torques). That includes the hip joint, knee joint, ankle joint, subtalar joint, midtarsal joints, midfoot joints, metatarsophalangeal joints and interphalangeal joints. The forefoot is also subjected to external forces from ground reaction force and from shoe reaction forces, and internal forces including tension, compression and shearing forces. Therefore, to focus only on "torque" in the forefoot, is somewhat like focusing only on the plantar receptors of the foot as being the only sensory organs which the central nervous system (CNS) can use to determine the optimal gait pattern during walking or running.

    2. In an unshod foot the deep transverse ligament is put under strain in a manner to which it is not in the shod foot and so accurate input may be lost to the CNS as to the torque being experienced in more proximal joints. I know of no research which supports the idea that the deep transverse ligament (DTL) is a significant contributor to the sensory input into the CNS. That being said, I also know of no research which supports the notion that the DTL is subjected to more strain when barefoot than when shod. In some shoes, such as athletic shoes, sandals, and many styles of boots, I would imagine the DTL is under similar strains as barefoot. In other shoes, such as ladies dress shoes and men's loafers, since they need to be more narrow in the toe-box for style or to stay on the foot, I would imagine the strains within the DTL would be somewhat less than when barefoot. Regardless of the type of shoe worn, or not worn, I again doubt any sensory contribution from the few afferent organs within the DTL (if there are any at all) have any impact on gait function.

    3. In terms of toe separation during late stance , footwear can be said to be acting as a splint. Finally, here is a sentence that makes sense from a biomechanical and physiological standpoint. Some footwear, specifically shoes which have a more narrow toe-box (i.e. narrow from medial to lateral), such as dress shoes for women, create a deforming force on the digits when being worn, which, over time, may create plastic deformation of the restraining elements of the metatarsophalangeal joints. These shoes create, over time, a deforming force of the digits within the transverse plane toward the central digits so that, when standing, the digits are all resting closer to each other, or touching the other digits. This toe pattern, with no separation between the digits, is commonly seen in older women and is nearly never seen in older individuals who have never worn shoes, or have worn sandals all their lives. Therefore, one could say that some footwear acts as "digital splints", but I wouldn't say that "forefoot torques" or "DTL strain" are important contributors to the digital deformities that occur over time from chronic use of "too-narrow toe-box" shoes.
  32. scotfoot

    scotfoot Well-Known Member

    A couple of brief pints Kevin .

    As a general comment I have not mentioned cutaneous plantar receptors in this thread as I don't see their input being detrimentally affected by footwear . The other point is really very simple .

    If I take off my shoes and socks , move one foot into a position were I am on the ball of that foot and twist the leg outwards I can fell the torque build around the ball of the foot and toes but not feel it in my knee or hip . The forefoot seems like a more sensitive instrument in this regard than other areas of the lower limb .
  33. I did your little test both barefoot and shod, couldn’t detect any difference in my conscious reception, but I have no idea what my sub-conscious CNS was up to.... I like skin and subcutaneous reception BTW. You know when you step on a Lego brick- withdrawal reflex initiated by those bad boys, most helpful. Wonder what would happen if we put something around your knee that would drag on the skin and then repeated that test? Rhetorical question, you will feel the torque at your knee, or rather the input from the cutaneous receptors, which is why your foot seems more “noisy” in your original test; which is why sensory neuropathy is such an arse.

    Shoes can induce sensory neuropathy- transient compression neuropathy, but I’ve never seen this in the plantar foot, rather on the hallux in those wearing shoes way too tight, i.e. football players wearing boots two sizes too small. Never seen it in a runner..
    Last edited: Dec 22, 2019
  34. scotfoot

    scotfoot Well-Known Member

    For the test first stand on both unshod feet on something like lino . For better balance hold onto a worktop or the like . Take most of your weight on the contralateral foot whist moving the subject foot onto the ball of the foot but with pressure also on the toes .
    Let's say the subject foot is the left foot . Now press down on of the ball of the left foot and toes (heel is off the ground ) and twist the foot and knee outwards . You should see the toes splay apart and even a blanching of the skin superior to the transverse ligament . If you twist to hard you might tear the skin between the toes so please don't do that .
  35. yes, the toes splay, but they do that whether I’m barefoot or in my Somnio running shoes that I’m wearing today. Tried to split the skin between my toes by pushing as hard as I could but didn’t manage that; can I suggest some lamasil for your tinea ? As Kevin said, some shoes will prevent that kinematic change by changing the kinetics acting on the forefoot- still doesn’t mean my CNS is “confused”! Rather I will feel that compression on my toes via the cutaneous receptors in my toes.

    How much does that patent owe you? I really don’t think that you are going to get your money back here. I reckon you’ve got a better chance pushing at the diabetic market. Merry Christmas.
    Last edited: Dec 22, 2019
  36. I'm all for a couple of pints. When is that happening?;)
  37. My house, Christmas Eve. Pop yourself over. Best wishes to you and family this Noel, boss.
  38. scotfoot

    scotfoot Well-Known Member

    Toes cant splayed unless foot can move freely within the shoe . But its laced in .

    Re patent let's see .
  39. Mine can in the laced-up shoes I’m wearing today. Your hypothesis though, the burden of proof is all yours.

    re: your patent: just remind me what it is that you're are trying to sell again? Oh, no need you’ve been spamming up Podiatry Arena all year with it. niiiiice #feelnoshame

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