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.

Yes, we are all twisted: Part 1

Developmentally speaking, that is.  Version and Torsion are the words we need to know. There are 3 normal versional changes that take place in the lower extremity development from infant to adult: rotation of the talar head/neck, tibial rotation, and femoral rotation  (see above). 

So, what is the difference between a torsion and version?

A version is a normal variation in the “twistedness” of a limb (longitudinally speaking) between its proximal and distal portions, representing a normal range of development (see femur above) .  An example is the head and neck of the femur has an angle of 8-12 degrees with respect the femoral condyles.

A torsion is the same condition with the amount of twist 1 to 2 standard deviations greater. An example is when the angle of the femoral neck and greater than 15 degrees, the condition of femoral ante torsion exists (see photo above).

There are at least 3 reasons you need to understand about developmental torsions and versions that occur with growth:

  1. Since they occur in the transverse (horizontal) plane, they affect the progression angle of the foot and thus gait
  2. They affect available ranges of motion of a limb (ex the femur needs to internally rotate 4-6 degrees for normal gait) and can cause pain and/or gait alterations
  3. They can affect the coronal (frontal) plane orientation of the lower limb, which can affect gait and shoe choices. A Rothbart foot type with an elevated 1st metatarsal head will often result in a varus (or inverted) position of the forefoot with respect to the rear foot.

In this series, we will explore these 3 major versional changes, one at a time.

The Gait Guys. Bald? Yes! Good looking? You bet! Yes, we are a little more twisted than most folks : )

All material copyright 2013 The Gait Guys/ The Homunculus Group. All rights reserved.  Please ask before recycling our stuff!

Podcast #21: You Cannot Beat the Brain

Show Link:http://thegaitguys.libsyn.com/pod-21-beating-the-brain-stretching

iTunes link:

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

1. Neuroscience Piece:

Scientists learn more about how inhibitory brain cells get excited

http://www.eurekalert.org/pub_releases/2013-01/ghsu-slm013013.php

2.Stretching and the 49ers

Links
http://www.huffingtonpost.com/estelle-underwood/stretching-exercise_b_2575768.html

http://online.wsj.com/article_email/SB10001424127887324734904578243930799732200-lMyQjAxMTAzMDIwNzEyNDcyWj.html?mod=wsj_valettop_email

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1004076/

The Case of the Apropulsive Cyborg Gait !

Can you identify the deficit in this gait pattern ?  Yes, the Cyborg looks like he is pulling his feet out of quicksand with each step, but why ?

Please do not read on until you watch the video a few times……watch the video again and improve your powers of observation and of what you know to be true biomechanically to identify the gait deficit. 

This is a recycled blog post from our archives in 2011.

For those in the medical field, you have likely seen this problem……but only unilaterally and that is why it might  not be initially familiar. HINT: It could be a lesion of S1 (the first sacral nerve root.)

As I (Dr. Allen) sit at my computer at home I have my desk oriented so that I look out of 4  windows onto a secluded quiet street that many runners in the area have adopted as a safe road to travel. Little do they know what I do for a living let alone that I am spying on them. But, some days I feel like I should hire some high school kid to just hand out my cards at the end of my driveway with an additional little typed up synopsis of their running flaws and list of probable injuries they either currently are milking, or have in the past (or are about to experience !).  And so, on my days off I get to work at my desk and look up and see more runners run than I do during a busy day at my clinic.  It is both a blessing and a curse. It seems that I just can never get away from this stuff. Heck, I was cooking up dinner the other night and I caught a glimpse of a trailer for a new TV show, and I was hit with seeing yet another interesting gait which prompted yet another call to my partner Ivo.  I said to him, “man, you think the celebrity and Gait Guys at the Movies was a neat idea (thanks again Bill !) wait until you hear this idea ! (you will get a sample of that very idea later in the week ! It should be a hit !). Ok, enough babbling. I wanted to create enough dialogue between my initial question so that your wandering eye would not look further down for the gait deficit by curious default. 

OK, so what did you see ?

if your answer was……..the Cyborg does not have any ankle plantarflexion whatsoever, you would be right.  And without any plantarflexion a person will always be in a forward lean like they are pushing a refrigerator across the floor.  Or better yet……like a hockey player who’s skates are laced as such to block out plantarflexion. Plantar flexion, eversion and abduction are all components of pronation; the action which makes the foot a “mobile adapter” rather than the rigid lever of supination we need to propel ourselves forward.  This is why they power out the movement to the side and off the inner edge of the blade (in fact, if you look closely at the right ankle of the Cyborg, you will see it flip out into external rotation very quickly just like a NHL pro……by turning out the foot into external rotation he can thus create a push off from the medial foot and big toe, utilizing the FHL to assist in push off.

The left foot (which does not do this), has nothing else to offer. 

In this gait, the body mass must lurch forward with an abrupt jerking motion (generated by the rectus abdominus, obliques and hip flexors) and heavy forward arm pump  to accelerate the mass forward enough to literally PULL the glued foot off of the ground (PULL rather than PUSH from the gastrocsoleus/gluteal complexes). This would be classified as an APROPULSIVE gait.  We have heard some in the coaching world would call this a PULL gait rather than a PUSH gait. 

So, I wonder what this cyborg’s foot would look like ? We bet there would be a massive toe long flexor response (and likely hammer toes) in an attempt to find something in the posterior compartment for forward propulsion.  Of course this phenomenon would likely not be seen in a broad based S1 nerve root lesion but in a non-ablative non-nerve related problem (ie, a functional problem with the posterior compartment) you could see compensations such as this from the other possible ankle plantarflexor muscles (tibialis posterior, plantaris, flexor digitorum longus).  

So, good video case……..hope you enjoyed the case of the Apropulsive Cyborg !

we remain, ……. The Gait Guys……..Shawn and Ivo