Walking on all Four limbs. The quad walkers. Uner Tan syndrome.

I wrote a multipart series on Uner Tan Syndrome, the people who walk on all fours years ago. Recently there has been a video of a young lady walking and running on all 4 limbs, like some kind of cat or canine. It triggered me to put this article up again on the research and thoughts behind this quadruped gait in humans. It worth rewinding today. We have written and updated several of our, and Dr. Tan's, theories and thoughts on it from direct communication with Dr. Tan. You can search for all the parts under "uner tan" in the search box.

"From the viewpoint of dynamic systems theory, it was concluded there may not be a single factor that predetermines human quadrupedalism in Uner Tan syndrome, but that it may involve self-organization, brain plasticity, and rewiring, from the many decentralized and local interactions among neuronal, genetic, and environmental subsystems."

Full Blog post here:

https://www.thegaitguys.com/…/the-hand-walkers-the-family-t…

The hand walkers: The family that walks on all fours. Part 1

Quadrupedalism and its commentary on human gait. To understand your athlete, your patient, your client, whatever your profession, you need to have a good understanding of neurodevelopment. If your client has some functional movement pattern flaws it could be from a delayed or expedited neurodevelopmental window. Generalized training and rehab will not correct an early or late window issue; often your work must be more specific.

When we began our journey into our daily writings on “The Gait Guys blog” we had no idea of the never ending tangents our writing would take pertaining to gait, human movement and locomotion. It has become plainly obvious over time that this blog will likely exist as long as we choose to continue it.

In 2006 we saw a documentary documentary entitled The Family That Walks On All Fours LINK: https://www.youtube.com/watch?v=ef3eKj4Pivk&feature=youtu.be
. . . and the video clip is from the documentary. It was a fascinating documentary and with our backgrounds in neurology, neurobiology, neuroscience, biomechanics and orthopedics we had more questions than the documentary touched upon. The documentary opened up many thoughts of neuro-development since we all start with a quadrupedal gait. But there had to be more to it than just this aspect because people eventually move through that neurologic window of development into bipedial gait. This has been in the back of our minds for many years now. Today we will touch upon this family and their challenges in moving through life, today we talk about Uner Tan syndrome, Unertan syndrome or UTS.

The original story is about the Ulas family of nineteen from rural southern Turkey. Tan described five members as walking with a quadrupedal gait using their feet and the palms of their hands as seen in this video. The affected family members were also severely mentally retarded and displayed very primitive speech and communication. Since his initial discovery several other families from other remote Turkish villages have also been discovered. In all the affected individuals dynamic balance was impaired during upright walking, and they habitually chose walking on all four extremities. Tan proposed that these are symptoms of Uner Tan syndrome.

UTS is a syndrome proposed by the Turkish evolutionary biologist Uner Tan. Persons affected by this syndrome walk with a quadrupedal locomotion and are afflicted with primitive speech, habitual quadrupedalism, impaired intelligence. Tan postulated that this is a plausible example of “backward evolution”. MRI brain scans showed changes in cerebellar development which you should know after a year of our blog reading means that balance and motor programming might be thus impaired. PET scans showed a decreased glucose metabolic activity in the cerebellum, vermis and, to a lesser extent the cerebral cortex in the majority of the patients. All of the families assessed had consanguineous marriages in their lineage suggesting autosomal recessive transmission. The syndrome was genetically heterogeneous. Since the initial discoveries more cases have been found, and these exhibit facultative quadrupedal locomotion, and in one case, late childhood onset. It has been suggested that the human quadrupedalism may, at least, be a phenotypic example of reverse evolution.

Neurodevelopment of Children:

Children typically go through predictable windows of neurodevelopment. Within a set time frame they should move from supine to rolling over. Then from prone they should learn to press up into a push up type posturing which sets up the spine, core and lower limbs to initiate the leg movements for crawling. Once crawling ensues then eventual standing and cruising follow. In some children, it is rare yet still not neurodevelopmentally abnormal, they move into a “bear crawl” type of locomotion where weight is born on the hands and feet (just as in our video today of UTS). Sometimes this window comes before bipedalism and sometimes afterwards but it should remain a short lived window that is progressed through as bipedalism becomes more skilled.

In studying Uner Tan Syndrome, Nicholas Humphrey, John Skoyles, and Roger Keynes have argued that their gait is due to two rare phenomena coming together.

“First, instead of initially crawling as infants on their knees, they started off learning to move around with a “bear crawl” on their feet.Second, due to their congenital brain impairment, they found balancing on two legs difficult.Because of this, their motor development was channeled into turning their bear crawl into a substitute for bipedalism.”

According to Tan in Open Neurol, 2010

It has been suggested that the human quadrupedalism may, at least, be a phenotypic example of reverse evolution. From the viewpoint of dynamic systems theory, it was concluded there may not be a single factor that predetermines human quadrupedalism in Uner Tan syndrome, but that it may involve self-organization, brain plasticity, and rewiring, from the many decentralized and local interactions among neuronal, genetic, and environmental subsystems.

There is much more we want to talk about on this mysterious syndrome and the tangents and ideas that come from it. We will do so in the coming weeks as we return to this case. We will talk about other aspects of neurodevelopment which should be interesting to you all since most our readers either are having children, will have them, or are watching them move through these neurologic windows. And we know that some of our readers are in the fields of therapy and medicine so this should reignite some thoughts of old and new. In future posts we will talk about cross crawl patterning in the brain, bear crawling, the use of the extensor muscles in upright posture and gait as well as other aspects of neurodevelopment gone wrong. We are not even close to being done with this video and all of its tangents. In the weeks to come we hope you will remain interested and excited to read more about its deep implications into normal and abnormal human gait.

author: Dr. Shawn Allen, one of the gait guys

References:

Open Neurol J.

2010 Jul 16;4:78-89. Uner tan syndrome: history, clinical evaluations, genetics, and the dynamics of human quadrupedalism.

Tan U

.Department of Physiology, Çukurova University, Medical School, 01330 Adana, Turkey.

link: http://www.ncbi.nlm.nih.gov/pubmed/21258577


Humphrey, N., Keynes, R. & Skoyles, J. R. (2005).

“Hand-walkers: five siblings who never stood up”

(PDF).

Discussion Paper

. London, UK: Centre for Philosophy of Natural and Social Science.

http://informahealthcare.com/…/abs/10.1080/00207450701667857

http://informahealthcare.com/…/abs/10.1080/00207450500455330

http://www.ncbi.nlm.nih.gov/pubmed…

https://www.youtube.com/watch?v=ef3eKj4Pivk&feature=youtu.be

Quadruped Patterns: Part 1 (redux)

Quadruped Patterns: Part 1
If you have been with us here at The Gait Guys for awhile, you will have read some articles where we discuss quadrupedal gait (link: Uner Tan Syndrome) and also heard us talk about CPG’s (Central Pattern Generators) which are neural networks that produce rhythmic patterned outputs without sensory feedback. You will have also read many of our articles on arm swing and how they are coordinated with the legs and opposite limb in a strategic fashion during gait and running gaits.

Lets get into it, full blog post here,

https://www.thegaitguys.com/thedailyblog/an-alternate-view-of-crawling-and-quadrupedal

 

An Alternate View of Crawling and Quadrupedal Motor Patterns: A Correlation to Free Solo Mountain Climbers ?

Quadruped Patterns: Part 1

In the last 3 years, if you have been with us here at The Gait Guys that long, you will have read some articles where we discuss quadrupedal gait (link: Uner Tan Syndrome) and also heard us talk about CPG’s (Central Pattern Generators) which are neural networks that produce rhythmic patterned outputs without sensory feedback. You will have also read many of our articles on arm swing and how they are coordinated with the legs and opposite limb in a strategic fashion during gait and running gaits. Through these articles, we have also eluded to some of the fruitless aspects of focusing solely on retraining arm swing in runners because of the deep neurologic interconnectedness to the lower limbs and to the CPG’s. 
IF you are interested in any of these articles we have written please feel free to visit our blog and type in the appropriate words (Uner Tan Syndrome, arm swing, cerebellum, cross over gait) into the Search box on the blog.

Here we briefly look at interconnected arm and leg function in crawling mechanics in a high functioning human (as compared to the Uner Tan Syndrome) in arguably the best solo free climber in the world, Alex Honnold. Here we will talk about the possible neurologic differences in climbers such as Alex as compared to other quadruped species. Primarily, there is suspect of an existing shift in the central pattern generators because of the extraordinary demand on pseudo-quadrupedal gait of climbing because of the demand on the upper limbs and their motorneuron pools to mobilize the organism up the mountain. The interlimb coordination in climbing and crawling biomechanics shares similar features to other quadrupeds, both primate and non-primate, because of similarities in our central pattern generators (CPG’s). New research has however determined that the spaciotemportal patterns of spinal cord activity that  helps to mediate and coordinate arm and leg function both centrally, and on a cord mediated level, significantly differ between the quadruped and bipedal gaits. In correlation to climbers such as Alex however, we need to keep it mind that the quadrupedal demands of a climber (vertical) vastly differ in some respects to those of a non-vertical quadrupedal gait such as in primates and those with Uner Tan Syndrome. This is obvious to the observer not only in the difference in quadrupedal “push-pull” that a climber uses and the center-of-mass (COM) differences.  To be more specific, a climber keeps the COM within the 4 limbs and close to the same surface plane as the hands and feet (mountain) while a primate,  human or Uner Tan person will “tent up” the pelvis and spine from the surface of contact.

What some of the research has determined is that in quadrupeds the lower limbs displayed reduced orientation yet increased ranges of kinematic coordination in alternative patterns such as diagonal and lateral coordination.  This was clearly different to the typical kinematics that are employed in upright bipedal locomotion. Furthermore, in skilled mountain climbers, these lateral and diagonal patterns are clearly more developed than in study controls largely due to repeated challenges and subsequent adaptive changes to these lateral and diagonal patterns.  What this seems to suggest is that there is a different demand and tax on the CPG’s and cord mediated neuromechanics moving from bipedal to quadrupedal locomotion. There seemed to be both advantages and disadvantages to both locomotion styles. Moving towards a more upright bipedal style of locomotion shows an increase in the lower spine (sacral motor pool) activity because of the increased and different demands on the musculature however at the potential cost to losing some of the skills and advantages of the lateral and diagonal quadrupedal skills.  Naturally, different CPG reorganization is necessary moving towards bipedalism because of these different weight bearing demands on the lower limbs but also due to the change from weight bearing upper limbs to more mobile upper limbs free to not only optimize the speed of bipedalism but also to enable the function of carrying objects during locomotion.

The take home seems to suggest that gait retraining is necessary as is the development of proper early crawling and quadruped locomotor patterns. Both will tax different motor pools within the spine and thus different central pattern generators (CPG). A orchestration of both seems to possibly offer the highest rewards and thus not only should crawling be a part of rehab and training but so should forward, lateral and diagonal pattern quadrupedal movements, on varying inclines for optimal benefits.  Certainly we need to do more work on this topic, the research is out there, but correlating the quad and bipedal is limited. We will keep you posted. Next week we will follow up on this quadrupedal topic with a video that will blow your mind ! So stay tuned !

Shawn and Ivo
The Gait Guys


Scand J Med Sci Sports. 2011 Oct;21(5):688-99. Idiosyncratic control of the center of mass in expert climbers. Zampagni ML, Brigadoi S, Schena F, Tosi P, Ivanenko YP.

J Neurophysiol. 2012 Jan;107(1):114-25. Features of hand-foot crawling behavior in human adults. Maclellan MJ, Ivanenko YP, Cappellini G, Sylos Labini F, Lacquaniti F.

The Cheetah man: A new perspective on Cross Crawl and neurologic patterning.

A few months ago we wrote a piece about Uner Tan Syndrome.  Here was a key point from that blog post (blog post link) and it links beautifully to our most recent controversial blog post on the “Bird Dog” rehab exercise (link here):

[In the video presented in that blog post, and in our “Bird Dog” post photo] there is ipsilateral interference between the foot and hand in this quadrupedal gait. In this diagonal quadrupedal locomotion (QL) the forward moving lower limb is impaired from further forward progression by the posting up (contact) hand of the same side. This would not occur if the QL gait was non-diagonal (ie. unilateral), the forward progression of the lower limb would be met with same time forward progression of the upper limb, allowing a larger striding out of both limbs.  This would enable faster locomotion without increasing cadence (which would be the only way of speeding up in the diagonal QL), at the possible limitation of necessitating greater unilateral truncal postural control (which is a typical problem in some of these Uner Tan Syndrome individuals who typically have profound truncal ataxia).  

So, why are we showing you the video above today ?  If you do not know, go read those 2 blog posts again and look more closely at the video above. At exactly 0:21 seconds into the video, at the slow motion section, you can see what we were talking about in the Bird Dog post last week, that being that the quadrupedal pattern that is neurologically substantiated is that when the right lower limb is in flexion, so is the left upper limb. (we will show these 2 photos in tomorrows post).  Where as, “Bird Dog” shows the opposite, that the contralateral upper limb will be in the opposite phase of the contralateral lower limb.

Who cares right ?  Well, it matters.  In the video above, this could be a problem because if the right leg is in flexion that means that the right arm will be moving into extension. This means that the knee and the hand will be running into each other (look at the baby photo here). As we discussed in the Uner Tan article this will impair faster quadrupedal locomotion. It is also one of the theories as to what may have pushed us to become bipedal and allow faster ambulation (there are many theories of course).  So, how then does this guy in the video move like a cheetah ? How is he going so fast with the quadrupedal pattern we have clearly outlined here ?

Within days a blog reader (Micheal L, thanks Michael) messaged us and said this:

  • As a person who likes what’s going on at MoveNat, this type of quadrupedal movement is referred to by them as contralateral movement and is how they teach people to crawl at their seminars. In CrossFit workouts, we also do bear crawls as an exercise, and I always try to maintain a contralateral gait. i.e. Right arm moves forward as left foot comes forwards and vice versa. 
    So, in other words, in the Uner Tan Syndrome (UTS) the gait is cumbersome and inefficient. In the video above and at MoveNat seminars, it’s a technique/skill.
    Did you guys intend for this comparison, or am I out in the cornfield on this?
    Here was Dr. Uner Tan  himself chiming in on the dialogue:
  • Üner Tan It is not the same type of locomotion, i.e., not “the diagonal-sequence quadrupedal locomotion”, which is also used by non-human primates.. .
    Michael: The guy runs so fast it’s hard for me to see it well. Okay, so with UTS the lower limb runs into the upper limb. In this video, his upper limb quickly gets out of the way, giving room for the lower limb (to further flex forward increasing swing phase forward step length). It’s just really hard to see it without slow motion. Thank you for clarifying.

As we said in last weeks post on all of this:
“Think about gait. Your right leg and left arm flex until about midstance, when they start to extend; the left leg and right arm are doing the opposite. At no point are the arm and opposite leg opposing one another. 
If you look at it neurologically, it is a crossed extensor reflex.  It is very similar to a protective reflex called the “flexor reflex” or “flexor reflex afferent”. 

In this video case today, it appeared on the surface because of the speed of this fella, that all that we have been talking about had been left in the dust. But, after looking at things closer and more slowly, the principles remain intact.  For now.
Just a little open thinking digging today. Hope you enjoyed.
Shawn and Ivo,
The gait guys

Podcast 56: Crawling, Neurodevel. & Foot Strike

A. Link to our server:

Direct Download: 

http://traffic.libsyn.com/thegaitguys/pod_57_final.mp3

Permalink: http://thegaitguys.libsyn.com/podcast-56-crawling-neurodevel-foot-strike

B. iTunes link:

https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138

C. Gait Guys online /download store (National Shoe Fit Certification and more !) :

http://store.payloadz.com/results/results.aspx?m=80204

D. other web based Gait Guys lectures:

www.onlinece.com   type in Dr. Waerlop or Dr. Allen,  ”Biomechanics”

________________________________________

* Today’s show notes:

Neuroscience

Human quadrupedalism is not an epiphenomenon caused by neurodevelopmental malformation and ataxia.  

“ a re-emergence of the ancestral diagonal QL, and (3) it may spontaneously emerge in humans with entirely normal brains, by taking advantage of neural networks such as central pattern generators that have been preserved for about 400 million years.”

References:

Front Neurol. 2012 Oct 25;3:154. doi: 10.3389/fneur.2012.00154. eCollection 2012. Karaca S1, Tan MTan U. Human quadrupedalism is not an epiphenomenon caused by neurodevelopmental malformation and ataxia.
2)  selectively removing torsions ? bunions ?  
FDA Panel Mulls Technique That Creates Babies Using DNA of 3 People
http://foxnewsinsider.com/2014/02/25/fda-panel-mulls-technique-creates-babies-using-dna-3-people
3) A Crazy Oculus Rift Hack Lets Men and Women Swap Bodies

http://www.wired.com/design/2014/02/crazy-oculus-rift-experiment-lets-men-women-swap-bodies/

“Minimum effective dose: Why less is more” - via Farnam Street blog. True for manual therapy, for sure. Lighten up, hack nervous system instead of trying to force structure to comply.http://www.farnamstreetblog.com/2014/02/the-minimum-effective-dose-why-less-is-more/
6) Unpowered Treadmills

A theory for bipedal gait ? Ipsilateral interference between the foot and hand in quadrupedal gait.

___________________________________________________

Human quadrupedalism is not an epiphenomenon caused by neurodevelopmental malformation and ataxia: Uner Tan Syndrome, Part 3

* Alert: Before you read this blog post you will do yourself a great degree of mental service by reading our 2 prior blog posts on this video.  There is an important learning progression here. Here are the links:

http://thegaitguys.tumblr.com/post/28332726553/the-hand-walkers-the-family-that-walks-on-all

http://thegaitguys.tumblr.com/post/78470419988/the-hand-walkers-part-2-uner-tan-syndrome-the

Note that in this video there is ipsilateral interference between the foot and hand in this quadrupedal gait. In this diagonal quadrupedal locomotion (QL) the forward moving lower limb is impaired from further forward progression by the posting up (contact) hand of the same side. This would not occur if the QL gait was non-diagonal (ie. unilateral), the forward progression of the lower limb would be met with same time forward progression of the upper limb, allowing a larger striding out of both limbs.  This would enable faster locomotion without increasing cadence (which would be the only way of speeding up in the diagonal QL), at the possible limitation of necessitating greater unilateral truncal postural control (which is a typical problem in some of these Uner Tan Syndrome individuals who typically have profound truncal ataxia).  

As the video progresses one can see that bipedal locomotion IS IN FACT POSSIBLE in Uner Tan syndrome individuals. 

This is the excerpt from the embedded video:

“Two adult siblings from a consanguineous famiy in Kars, Turkey, exhibited Uner Tan syndrome with severe mental retardation, and no speech, but with some developmental differences.. 
There was no homozygocity in the genetic analysis, but the extremely low socio-economic status suggested epigenetic changes occurred during pre- and post-natal
development. 
Quadrupedal locomotion in cases with Uner Tan syndrome exhibit interference between the ipsilateral extremities, and this also occurred in all tetrapods with diagonal sequence QL since this form of locomotion appeared around 400 MYA. 
The ipsilateral limb interference might have been the triggering factor for bipedal locomotion in our ancestors, and walking upright would enhance their chances of survival, because of the benefits in the visual and manual domains. The ipsilateral interference theory is a novel theory for the evolution of bipedalism in human beings, and was first proposed by Uner Tan in 2014.”

As Karaca, Tan & Tan (1) discussed in their article:

“In discussions of the origins of the habitual QL observed in Uner Tan syndrome, it was argued that this quadrupedalism might be an epiphenomenon caused by neurodevelopmental malformation and severe truncal ataxia (Herz et al., 2008). The present work will show that this argument may be untenable, presenting two individuals with QL who do not exhibit ataxia, and who have entirely normal brain images and cognitive functions.”

As we mentioned in our last blog post,

“Tan and Ozcelik mentioned in their recent research, in UTS the obligate diagonal QL was associated with some genetic mutations and cerebellovermial hypoplasia, and was seen as an adaptive self-organizing response to limited balance. On the other  hand, the present work showed that human QL may spontaneously occur in humans with an unimpaired brain, probably using the ancestral locomotor networks for the diagonal sequence preserved for about the last 400 million years. (Shapiro and Raichien, 2005; Reilly et al., 2006)." (1)

Kind of brings some new "slap in the face” thoughts to the rehab “bird dog” exercise doesn’t it !  Driving a 400 million year old quadruped motor pattern (ya, ya, we know it is a early-window primitive cross crawl infant neurodevelopmental pattern, we have been to Pavel Kolar seminars. Don’t try to argue, just think past all this. Go get a beer or walk in the park and cogitate on this a bit, it is important.)

If you want to dive deeper into this kind of work,  you may want to go and look at some of our recent work on Arm Swing here. But don’t forget to watch this video above again and pay close attention to what we mentioned here.

We received this video on Monday (March 3, 2014) directly from Dr. Uner Tan himself in Turkey. We are very grateful for all that he has been sharing with us behind the scenes and we are grateful for his research and for this budding relationship.  Thank you Dr. Tan !  

Dr. Shawn Allen, one of The Gait Guys

Reference: 

1. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3480821/

The Hand Walkers, Part 2. Uner Tan Syndrome, the new research.

A year ago we wrote our first piece on Uner Tan Syndrome. We have always been interested in the neurodevelopmental windows of children and their process of moving through the various movement phases in the hopes of gaining clean upright bipedal gait. In our clinics daily we see many soft signs of sensory-motor pattern aberrancies that result in foot problems such as lack of pronatory control, or torsional long bone abnormalities and failures to protect frontal plane deviations (to name a very small few). In fact, these soft seonsory-motor signs and patterns can be found globally if one knows what to look for.  In our clinics we rarely see the serious neuro-developmental problems but Uner Tan Syndrome (UTS) has always been one of interest to us. We recently received a very kind email from Turkey, from Dr. Uner Tan himself, asking to reference some of our work so this was a serious honor.  The email sparked us to look into his research to look for newer work and we were happy to find it. Before we start into the new research findings, you will want to take a few minutes to read our last blog piece on Uner Tan Syndrome: The Hand Walkers.

http://thegaitguys.tumblr.com/post/28332726553/the-hand-walkers-the-family-that-walks-on-all

This previous blog post discussed much of the research that was current at the time.  The following was from our previous blog post  on UTS  

UTS is a syndrome proposed by the Turkish evolutionary biologist Uner Tan. Persons affected by this syndrome walk with a quadrupedal locomotion and are afflicted with primitive speech, habitual quadrupedalism, impaired intelligence. Tan postulated that this is a plausible example of “backward evolution”. MRI brain scans showed changes in cerebellar development which you should know after a year of our blog reading means that balance and motor programming might be thus impaired.  PET scans showed a decreased glucose metabolic activity in the cerebellum, vermis and, to a lesser extent the cerebral cortex in the majority of the patients. All of the families assessed had consanguineous marriages in their lineage suggesting autosomal recessive transmission. The syndrome was genetically heterogeneous.  

However, some startling new research has recently surfaced and if most are paying attention, they will see the value in our 1000+ blog posts here at The Gait Guys but more so discover Dr. Tan’s most startling conclusion from the Frontiers in Neurology article below. We are currently moving through the most recent research so you will want to check in with us again soon for our follow up blog posts on this topic. 

Here was Dr. Tan’s et al abstract conclusion of his most recent research, and we think it is earth shattering.

Human quadrupedalism is not an epiphenomenon caused by neurodevelopmental malformation and ataxia.  

Two cases with quadrupedal locomotion (QL) were presented. In both cases, cognitive and psychiatric functions were normal and, no neurological deficits were observed, except for a sequel paralysis of left leg in Case 2. It was suggested that human QL (1) should not be considered as an epiphenomenon caused by neurodevelopmental malformation and ataxia, but (2) may be considered as a re-emergence of the ancestral diagonal QL, and (3) it may spontaneously emerge in humans with entirely normal brains, by taking advantage of neural networks such as central pattern generators that have been preserved for about 400 million years.

We will have more to come shortly, but for now, realizing that the human brain, even when normal, can take advantage of neural networks encompassing Central Pattern Generators (CPG’s) that have been suppressed for 400 million years is startling information in our opinion.

Check back in with us soon.

Dr. Shawn Allen, one of the gait guys

References:

Front Neurol. 2012 Oct 25;3:154. doi: 10.3389/fneur.2012.00154. eCollection 2012. Karaca S1, Tan MTan U. Human quadrupedalism is not an epiphenomenon caused by neurodevelopmental malformation and ataxia.

An Alternate View of Crawling and Quadrupedal Motor Patterns: A Correlation to Free Solo Mountain Climbers ?

Quadruped Patterns: Part 1

In the last 3 years, if you have been with us here at The Gait Guys that long, you will have read some articles where we discuss quadrupedal gait (link: Uner Tan Syndrome) and also heard us talk about CPG’s (Central Pattern Generators) which are neural networks that produce rhythmic patterned outputs without sensory feedback. You will have also read many of our articles on arm swing and how they are coordinated with the legs and opposite limb in a strategic fashion during gait and running gaits. Through these articles, we have also eluded to some of the fruitless aspects of focusing solely on retraining arm swing in runners because of the deep neurologic interconnectedness to the lower limbs and to the CPG’s. 
IF you are interested in any of these articles we have written please feel free to visit our blog and type in the appropriate words (Uner Tan Syndrome, arm swing, cerebellum, cross over gait) into the Search box on the blog.

Here we briefly look at interconnected arm and leg function in crawling mechanics in a high functioning human (as compared to the Uner Tan Syndrome) in arguably the best solo free climber in the world, Alex Honnold. Here we will talk about the possible neurologic differences in climbers such as Alex as compared to other quadruped species. Primarily, there is suspect of an existing shift in the central pattern generators because of the extraordinary demand on pseudo-quadrupedal gait of climbing because of the demand on the upper limbs and their motorneuron pools to mobilize the organism up the mountain. The interlimb coordination in climbing and crawling biomechanics shares similar features to other quadrupeds, both primate and non-primate, because of similarities in our central pattern generators (CPG’s). New research has however determined that the spaciotemportal patterns of spinal cord activity that  helps to mediate and coordinate arm and leg function both centrally, and on a cord mediated level, significantly differ between the quadruped and bipedal gaits. In correlation to climbers such as Alex however, we need to keep it mind that the quadrupedal demands of a climber (vertical) vastly differ in some respects to those of a non-vertical quadrupedal gait such as in primates and those with Uner Tan Syndrome. This is obvious to the observer not only in the difference in quadrupedal “push-pull” that a climber uses and the center-of-mass (COM) differences.  To be more specific, a climber keeps the COM within the 4 limbs and close to the same surface plane as the hands and feet (mountain) while a primate,  human or Uner Tan person will “tent up” the pelvis and spine from the surface of contact.

What some of the research has determined is that in quadrupeds the lower limbs displayed reduced orientation yet increased ranges of kinematic coordination in alternative patterns such as diagonal and lateral coordination.  This was clearly different to the typical kinematics that are employed in upright bipedal locomotion. Furthermore, in skilled mountain climbers, these lateral and diagonal patterns are clearly more developed than in study controls largely due to repeated challenges and subsequent adaptive changes to these lateral and diagonal patterns.  What this seems to suggest is that there is a different demand and tax on the CPG’s and cord mediated neuromechanics moving from bipedal to quadrupedal locomotion. There seemed to be both advantages and disadvantages to both locomotion styles. Moving towards a more upright bipedal style of locomotion shows an increase in the lower spine (sacral motor pool) activity because of the increased and different demands on the musculature however at the potential cost to losing some of the skills and advantages of the lateral and diagonal quadrupedal skills.  Naturally, different CPG reorganization is necessary moving towards bipedalism because of these different weight bearing demands on the lower limbs but also due to the change from weight bearing upper limbs to more mobile upper limbs free to not only optimize the speed of bipedalism but also to enable the function of carrying objects during locomotion.

The take home seems to suggest that gait retraining is necessary as is the development of proper early crawling and quadruped locomotor patterns. Both will tax different motor pools within the spine and thus different central pattern generators (CPG). A orchestration of both seems to possibly offer the highest rewards and thus not only should crawling be a part of rehab and training but so should forward, lateral and diagonal pattern quadrupedal movements, on varying inclines for optimal benefits.  Certainly we need to do more work on this topic, the research is out there, but correlating the quad and bipedal is limited. We will keep you posted. Next week we will follow up on this quadrupedal topic with a video that will blow your mind ! So stay tuned !

Shawn and Ivo
The Gait Guys


Scand J Med Sci Sports. 2011 Oct;21(5):688-99. Idiosyncratic control of the center of mass in expert climbers. Zampagni ML, Brigadoi S, Schena F, Tosi P, Ivanenko YP.

J Neurophysiol. 2012 Jan;107(1):114-25. Features of hand-foot crawling behavior in human adults. Maclellan MJ, Ivanenko YP, Cappellini G, Sylos Labini F, Lacquaniti F.