We always think of ourselves as the CSI or NCIS geeks of gait. We were aware of forensic analysis of footprints and this article is just the icing on the cake!

article source: http://www.google.com/hostednews/afp/article/ALeqM5jhIh9jpQmYAgl6Rv0uBjNQgT1ItQ?docId=CNG.4ecd62b490d0f49529b2cfb2c331d332.481

Security first: When a footstep is like a fingerprint

(AFP) – 1 day ago   

PARIS — How a bare foot strikes the ground as one walks reveals your identity almost as well as a fingerprint, according to a study released Wednesday.

The discovery means that one day retinal scans, voice recognition and old-fashioned mugshots may be joined by foot-pressure patterns as a means of confirming ID, it suggests.

Previous research has shown that everyone has a unique stride. Computers can determine “gait patterns” – the way a person walks, saunters, swaggers or sashays – with up to 90-percent accuracy.

Scientists led by Todd Pataky at Shinshu University in Tokida, Japan, looked at enhancing this finding by measuring how the foot hits and leaves the ground during walking.

They used 3-D image processing and a technique called image extraction to analyse the heel strike, roll-to-forefoot and push-off by the toes among 104 volunteers.

Footstep patterns were matched to the individual with 99.6 percent accuracy, according to their paper, published on Wednesday in Britain’s Journal of the Royal Society Interface.

The study is “proof of concept,” meaning that it was carried out in experimental conditions among volunteers who were barefoot to see whether the theory was sound.

In an email exchange with AFP, said the technology would be useful in security checks.

But it would only work in situations where an individual wants to be recognised, “since anyone can modify their gait,” he explained.

“Automated airport security checks, ATM security, controlled building access – in all these cases, an individual could walk normally to be positively identified.”

Further work is needed to see whether feet that are shod throw up similar telltale patterns.

“We have some pilot data for walking with shoes, but have not yet conducted systematic testing,” Pataky said.

Too cool, eh?

Ivo and Shawn

Evolved to run: How we keep our noodle steady while we run.→

Have you ever given thought to your head movements during running or walking ? Ever wonder why the world doesn’t seem to bound around as we move ? Wonder why things look different through your eyes when you yourself are running as compared to when you are watching the nauseating jerky video of someone wearing a camera on their head ?

Bryce Vickmark for The New York Times interviewed Dr. Lieberman of the Harvard Nature study…. here is a quote from that interview.

“We (Lieberman) realized that there were special features in the human neck that enable us to keep our heads still. That gives us an evolutionary advantage because it helps us avoid falls and injuries. And this seemed like evidence of natural selection in our ability to run, an important factor in how we became hunters rather than just foragers and got access to richer foods, which fueled the evolution of our big brains.”

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Gait Guys say this….. “The ability to see clearly while moving / running / hunting is a well rooted primitive neurologic function in man. The visual-motor system (oculomotor system) is capable of assimilating the visual information and making calculations for the small head displacements that occur with movement via neural mechanisms that control three-dimensional head posture while coordinating three-dimensional eye orientation. The body’s movements as a whole (eye, head and body) are part of a coordinated series of sensory-motor events that are used to voluntarily reorient the axis of gaze between objects.  Body movements themselves can make a predictable contribution to gaze shifts and one study (link) has shown that single neurons (yes, one small neuron all by itself) can code motor commands to move the body as well as the head and eyes.  It is a finely tuned system, an amazing system.  One we rarely appreciate anymore since running during a hunt for food no longer occurs in urban America.  Of course this function is seamlessly tested everyday in athletes, unless of course you are a football or other impact sport athlete, and have accelerated your noggin one too many times.  Ask any aging boxer or ex-football player how their visual-motor system is doing ! (and since it is NFL and high school football season….. here is support for those dropped endzone passes in the concussed wide receivers...LINK and. LINK)

NY Times link: for the Lieberman article.

We are The Gait Guys…….. running and hunting outside the box everyday, looking for answers.

We thought this was pretty funny. The moral of the story? Always remember to change your sox…

Have a great Friday

Ivo and Shawn

So, does the angle your foot strikes the ground really matter? With all the talk about minimalistic training and striking under the body being less stress on the human frame and more efficient, you would think so. Here is one study that seems to support that premise.

from the studies conclusion: “Our results indicate that individuals with a larger knee angle (i.e., greater extension) 50 ms prior to initial contact (IC) experience a higher ROL  (Rate of loading) during gait and have poorer proprioceptive scores.”

Proprioception, gait kinematics, and rate of loading during walking: are they related? Riskowski JL, Mikesky AE, Bahamonde RE, Alvey TV 3rd, Burr DB.

J Musculoskelet Neuronal Interact. 2005 Oct-Dec;5(4):379-87.

http://www.ncbi.nlm.nih.gov/pubmed/16340143

Helping to promote gait literacy…We are…The Gait guys

Something a little lighter…..

Borrowed from one of our good friend and fellow physicians site, Dr Mark Cucuzella’s Freedom Run http://freedomsrun.org/  . This clip is truly inspirational.

Ivo and Shawn

This week on Neuromechanics Weekly:

The necessary factors for muscle contraction. Stay tuned for what controls muscle tone next week.

Like this video, tell your friends. Don’t like it? Please tell us!

Shawn and Ivo

Here are some excerpts from a talk we did earlier in 2011. Dr. Shawn Allen talks to a private industry group about shoes, shod and unshod ambulation, the research based facts from both old and new studies, and thoughts about the benefits and caveats of going into minimalistic footwear or barefoot.
Thank you for watching our video, please feel free to share it with anyone and everyone. We have lots of other videos here on youtube.
Shawn and Ivo…..The Gait Guys

http://naturalrunningcenter.com/2011/08/22/apolo-ohno-plans-run-york-city-marathon-gait-guys-check-form/

Check out another fun video we did for our friends at thenaturalrunningcenter.com and zero-drop.com featuring Apolo Ohno.

photo credit: taminator’s photostream

Defective Running Shoes as a contributing Factor in Plantar Fascitis in a Triathlete

Wilk B, Fisher K, Guitierrez W: JOSPT 2000;30(1):21-31

http://www.jospt.org/issues/articleID.407/article_detail.asp

Overview: Case study of 40 yo male triathlete who developed R sided plantar fascitis after completing a half ironman (2K swim, 90K bike, 21K run). The study describes the factors contributing to the injury, the rehab process, and shoe construction along with the symptoms of plantar fascitis.

Authors Conclusion: A running shoe manufacturing defect was found that possibly contributed to the development of plantar fascitis. Assessing athletic shoe construction may prevent lower extremity overuse syndromes.

What The Gait Guys Say: Plantar fascitis is something we see clinically many times in our practices. It is often due to overpronation of the midtarsal joint (talo-navicular and calcaneo-cuboid) in midstance, with insufficient supination from late midstance through preswing.  Thus, this over pronation causing overloading of the plantar fascia and windlass mechanism, resulting in increased torsional forces and micro-tearing at it’s proximal calcaneal (and sometimes distal) attachments. This causes local pain, swelling and inflammation, particularly at the calcaneal attachment site, which is alleviated by rest, ice and analgesics. As we have shared many times now, this over pronation does not have to be a local cause, it could be necessary from insufficient internal rotation of the hip or from other factors.

In this study, the Right shoe upper was canted medially on the midsoles, believed due to it not being glued perpendicularly (as we often see inspecting a shoe from behind, especially Asics Kayano’s in our experience). The authors state they felt this contributed to excessive inward rolling of the right foot, contributing to overpronation.

The authors make the following recommendations about shoe inspection:

• The shoe should be glued together securely
• The upper should be glued straight (perpendicular) onto the midsole. The shoe, viewed from behind should have a horizontal heel counter and vertical upper
• The sole of the shoe should be level to the surface on which it is resting (ie no medial to lateral motion should be present) You can test this by attempting to “rock” the shoe from side to side
• The shoes should not roll excessively inward or outward when resting on a level surface (ie when rolling from P to A) You can test this by rocking the shoe from A to P
• Air and gel pockets should be inflated evenly. This can be tested manually by pressing into them and checking for uniformity.

A nice rehab protocol is also outlined over a 4 week period.

Bottom Line: It pays to be shoe nerd. Shoes can help or hurt. We see manufacturers defects in shoes every day and tell clients to return the shoe; in fact some we collect  to use to show people. A rearfoot varus in a shoe will help to slow pronation. This may actually be beneficial for overpronators but detrimental for supinators. Some defects can be helpful but try and find defect free shoes. Stay away from “2nds” at cheapie stores and online specials. There is usually a reason they are being sold so cheaply. EVA’s have a shelf life and will break down over time. You must be able to not only recommend the appropriate shoe for your patient, based on their evaluation and gait analysis, but you need to inspect their footwear carefully and teach them to do the same.

The original shoe nerds….Shawn and Ivo

And now, some light reading for a Saturday….

Review of knee proprioception and the relation to extremity function after an anterior cruciate ligament rupture.

J Orthop Sports Phys Ther. 2001 Oct;31(10):567-7

http://www.ncbi.nlm.nih.gov/pubmed/11665744

What the Gait Guys say about this article:

Aren’t you glad you have mechanoreceptors?

As we have discussed in other posts, proprioception is subserved by cutaneous receptors in the skin (pacinian corpuscles, Ruffini endings, etc.), joint mechanoreceptors (types I,II,III and IV) and muscle spindles (nuclear bag and nuclear chain fibers) . It is both conscious and unconscious and travels in two  main pathways in the nervous system.

Conscious proprioception (awareness of where a joint or body part is in space or action) arises from the peripheral mechanoreceptors in the skin and joints and travels in the dorsal column system (an ascending spinal cord information highway) to ultimately end in the thalamus of the brain, where the information is relayed to the cerebral cortex.

Unconscious proprioception arises from joint mechanoreceptors and muscle spindles and travels in the spino-cerebellar pathways to end in the midline vermis and flocculonodular lobes of the cerebellum.

Conscious proprioceptive information is relayed to other areas of the cortex and the cerebellum. Unconscious proprioceptive information is relayed from the cerebellum to the red nucleus to the thalamus and back to the cortex, to get integrated with the conscious proprioceptive information. This information is then sent down the spinal cord to effect a response in the periphery. As you can see, there is a constant feed back loop between the proprioceptors, the cerebellum and the cerebral cortex. This is what allow us to be balanced and coordinated in our movements and actions.

The ACL is blessed with type I, II and IV mechanoreceptors (Knee Surgery, Sports Traumatology, Arthroscopy Volume 9, Number 6)   We remember that type I mechanoreceptors exist in the periphery of a joint capsule (or in this case, the periphery of the ACL) and are largely tonic in function (ie: they fire all the time) and type II are located deeper in the joint (or deeper in the ACL) and are largely phasic (ie they fire with movement). Type IV mechanoreceptors are largely pain receptors and anyone who has injured his knee can tell you all about them.

The article does a great job reviewing the importance of proprioception and how it relates to knee function and concludes “A higher physiological sensitivity to detecting a passive joint motion closer to full extension has been found both experimentally and clinically, which may protect the joint due to the close proximity to the limit of joint motion. Proprioception has been found to have a relation to subjective knee function, and patients with symptomatic ACL deficiency seem to have larger deficits than asymptomatic individuals.”  Bottom line, never quit on the rehab and training of an ACL deficient knee until the absolute best outcome has unequivocally been achieved with certainty that no further improvement can be achieved…… absolute certainty.  Too many stop shy of certainty, and your brain will know it.  And it will show it in small gait, running and athletic skills.

Yup, this is some heavy stuff, but hey…you’re reading it, right?  If we didn’t explain it in detail you might not believe that WE are The Gait Guys ……. more than just foot and shoe guys. After all, there is a brain attached to the other end calling the shots.

Sorting it out so you don’t have to…We remain…The Gait Guys

Ah yes, the Ia and type II afferents.

One of our favorites! Acting as a sentinel from the muscle spindle, concentrated in the antigravity and extensor musculature, Ia and type II afferents live in the belly of the muscle and send information regarding length and rate of change of length to the CNS via the spino cerebellar and inferior olivary pathways. In more simpler terms, think of muscle spindles as small computer chips embedded in the muscle and using la and type II afferents the team act as volume controls helping to set the tone of the muscle and it responsiveness to stretch. If they are active, they make a muscle more sensitive to stretch.

So what does that mean? Muscle spindles turn up the volume or sensitivity of the muscles response to stretch. Remember when we stretch a muscle, it’s response is to contract. Think about when a doctor tests your reflexes. What makes them more or less reactive? You guessed it, the muscle spindle; which is a reflection of what is going on in the higher centers of the brain. The muscle spindles level of excitation is based on the sum total of all information acting on the gamma motor neuron (ie the neuron going to the muscle spindle) in the spinal cord. That includes all the afferent (ie. sensory) information coming in (things like pain can make it more or less active) as well as information descending from higher centers (like the brain, brainstem and cerebellum) which will again influence it at the spinal cord level.

So we found this cool study that looks at spindles and supports their actions:

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http://www.ncbi.nlm.nih.gov/pubmed/19451207

J Physiol. 2009 Jul 1;587(Pt 13):3375-82. Epub 2009 May 18.

Mechanical and neural stretch responses of the human soleus muscle at different walking speeds.

Cronin NJ, Ishikawa M, Grey MJ, af Klint R, Komi PV, Avela J, Sinkjaer T, Voigt M.

At increased speeds of walking, the muscles themselves (particularly the soleus in this study) become stiffer due to changes in spindle responsiveness. The decline in amplitude and velocity of stretch of the soleus muscle fasicles with increasing walking speeds was NOT accompanied by a change in muscle spindle amplitude, as was hypothesized.

Clinically, this means that the spindles were STILL RESPONSIVE to stretch, even though the characteristics of the muscle changed with greater speeds of action. This may be one of the reasons you may injure yourself when moving or running quickly; the muscle becomes stiffer and the spindle action remains constant (the volume is UP).

Thankfully, we have another system that can intervene (sometimes) when the system is overloaded, and take the stress of the muscle. This is due to the golgi tendon organ; but that is a post for another day…

Geeking out and exploring the subtleties of the neurology as it relates to the system, we remain…The Gait Guys

You have heard of minimalist shoes?

Be scared. Be very scared! Brought to you by our friends at Zero-drop.com:

Maximalist Shoes!

Yikes…what will they think of next?

Your favorite shoe geeks….Shawn and Ivo

Shod vs. Unshod : What the Lieberman-Harvard study really said.

Shod vs. Unshod : What the Lieberman-Harvard study really said.

Thanks to OwenAnderson of  Educatedrunner.com for this excellent article.

http://educatedrunner.com/Blog/tabid/633/articleType/ArticleView/articleId/797/BAREFOOT-RUNNING-WHAT-THE-HARVARD-STUDY-REALLY-SAID.aspx

If you are paying attention to everything that is going on, you want to read this well thought out article.  The Gait Guys are digesting this article and we will render our thoughts and opinions shortly.  But, differing points of view, when laid out logically and with sound reason, deserve consideration. This is how the truth is eventually discovered.

Give this article a productive and attentive read.  We will get back to you shortly.

Summary statement seems to be this….. (quoted word from word from the article).

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“Ironically, the popular press has been using the Harvard study as a launching pad for the idea that barefoot running is healthier than shod ambling, even though Lieberman’s paper provided no data at all to test the idea that barefoot running lowers the risk of running injuries!

  Here’s what Lieberman et al actually found:  

(A) Habitually shod runners (groups 1 and 5 from above) who grew up wearing shoes are usually rear-foot strikers (RFS), meaning that their heels make the first impacts with the ground during running, right at the beginning of the stance phase of gait. This is not new information. The strong link between running in shoes and heel-striking has been known for many years.  

(B) Runners who grew up running barefooted or who switched to running barefooted (groups 2, 3, and 4) are generally fore-foot strikers (FFS), meaning that they tend to land initially on the balls of their feet while running, after which their heels drop down to make contact with the ground. Again, this is nothing new – the tight connection between barefoot running and FFS (and also MFS, mid-foot striking) has been general knowledge for years.  

© Impact forces transmitted through the foot, ankle, and leg immediately after impact with the ground are about three times greater in shod runners using RFS, compared with barefoot runners with FFS. Some – but not all - previous studies have shown this same relationship, with RFS producing greater impact force during the first portion of stance, compared with MFS and FFS. The sudden rise in force with RFS, immediately after ground contact, is known as the “impact transient.” The disparity in impact transient between barefoot and shod running represents a “foundation” for the belief that barefoot running is “safer” and less injury producing. While this appears to be logical thinking, it is important to know that no study has ever shown that greater impact forces during the first portion of stance magnify the risk of running injury.  

(D) Rates of loading of impact force are actually quite similar between shod RFS runners and barefoot FFS athletes (Figure 2b from the Nature paper). The rate at which impact force is loaded into the leg has also been suggested to be a risk factor for injury, although convincing proof of this notion does not exist.  

(E) During the early stance phase of barefoot FFS running, there is greater knee flexion, greater dorsi-flexion at the ankle, and a 74-percent-greater drop in the center of mass, compared with shod RFS running. “Vertical compliance” is defined as the drop in the runner’s center of mass relative to the vertical force during the impact period of stance, and it is obviously greater in barefoot FFS running, compared with shod RFS. Vertical compliance varies as a function of running-surface hardness, and this is why force-loading rates are similar for barefoot FFS runners over a wide array of running surfaces (the runners adjust compliance according to surface). This is not novel information, however.  

(F) During barefoot FFS ambling, the ground reaction force torques the foot around the ankle (and therefore increases the amount of work carried out by the ankle, compared with shod RFS running). With shod RFS running, the ankle converts little impact energy into rotational energy. Potentially, this could spike the rate of ankle-area injuries (for example in the Achilles tendon and calf) for barefoot runners, although this hypothesis has not been tested.  

And that was pretty much it! The Nature investigation did disclose some interesting information about the effective mass of the foot and shank (which we won’t discuss here), but it offered no other information about the potential links between barefoot running and either injury or performance.   And that’s why it’s too early for you to consider changing from shod to barefoot running, unless such a shift would be a lot of fun for you. 

There’s just no proof that barefoot running will reduce your risk of injury or make you faster.   In fact, it’s important to remember that most injuries in running are caused by an imbalance between the strain and micro-damage experienced by a muscle or connective tissue during training and the tissue’s ability to recover from such stress. This imbalance can occur when training is conducted shod – or barefooted! A weak or overly tight hamstring muscle which has been undone by excessive mileage won’t care if its owner was running barefooted or wearing shoes – it will still feel the pain. ” -

Owen Andersson, http://educatedrunner.com/Blog/tabid/633/articleType/ArticleView/articleId/797/BAREFOOT-RUNNING-WHAT-THE-HARVARD-STUDY-REALLY-SAID.aspx

In this weeks Neuromechanics weekly, Dr Waerlop takes us from the cortex to the muscle spindle. The journey through the neuraxis continues….

So, the question you need to ask is why they cut the leg off and transplanted the foot/ankle 180 at the lower femur.

If you think about it, it is because he needed a joint to flex like his old knee.  If they put the foot on forward there would be no knee bend (ie. his knee would have only bent as much  as you can point your foot…….the motion of ankle plantarflexion.  This would have been extremely insufficient in range to move as well as this fella is moving. )

By doing a rotation transplasty and putting the foot on backwards he could take advantage of the large range of ankle dorsiflexion.  They talk about the toes alot in this video but this really has nothing to do with the success of this surgery, functionally anyways. The genius of this surgery was using the ankle as a knee hinge. 

Pretty amazing stuff.  Enjoy the brain-twister in understanding how he is using ankle dorsiflexion to replicate knee flexion.  !!!!

taking Gait to another dimension……… Shawn and Ivo

Here Dr. Allen of The Gait Guys introduces some of the initial information necessary to understand proper shoe fit. Topics include body anatomy, shoe anatomy, physiology, biomechanics and compensation patterns. This was part of a private industry lecture where The Gait Guys were asked to help improve the understanding of the concepts critical to better shoe industry choices.

Ivo and Shawn …. what we do while you are sleeping.

our version of crop circles !

watch for signs of our presence at your local beach or wheat field near you !

you are not alone…….

photo from . http://nakedonsharppointystuff.blogspot.com/

So. How did you do?

As you can see, this individual lists to the R upon weight bearing on that side (midstance); did you pick up the increased progression angle of the foot on that side? How about the mild genu valgus?

Why would someone walk like this? There are a few plausible explanations.

1. he has a weak gluteus medius on the R side.

2. he has a R short leg and needs to lean to that side to get the long leg side (L) to clear.

3. impaired left ankle rocker (causing premature heel rise and left side early departure) could also cause him to accelerate onto the right as well.

His options to compensate are to either lean to the weak side ® or to shift his pelvis to the weak side ®. He could also circumduct the leg or flex the thigh to get that side to clear the ground. He has a mild BL circumdcution, probably to clear the knee from the opposite one.

His increased arm swing on the L is to help propel him forward, most likely due to weakness of the external obliques to assist in initiation of flexion of the thigh, and weakness of the gluteus medius, which also helps to propel the leg forward. He also does not push off adequately with the R leg; This is probably due to loss of hip extension and inadequate ankle rocker on that side.

The increased progression angle on the R helps to stabilize his body weight because he is leaning the torso to the R and his center of gravity moves right as well (he makes a wider base for himself)

Yup, you’re a geek!   We remain The Geeks of Gait…Ivo and Shawn

oh look, it appears (but a little hard to tell) ……but it appears we have a casualty !

here is what her ankle is saying …..

“oh no, we do not have enough ankle dorsiflexion to be on this bad boy…….so, who wants to take it guys…….. how about you hyperpronate Mr. Arch, and to help we will drive Mr. Knee medially."  ?

better have enough ankle dorsiflexion if you are gonna play with this monster !