Watch this girl walk. What is the most striking feature of her gait?

Is it the genu valgus? Is it her progression angle (or lack of?) Her Left sided increased arm swing? Her body shift to the left in Left stance phase?

We would like to discuss her progression angle. We remember that the progression angle is the angle the foot makes with the ground at heel strike and through stance phase (another way of describing it is, Are your feet turned out or turned in?). It is determined by many factors (forefoot position, subtalar joint angle, tibial abnormalities, femoral torsions, etc). In this case it is highly suspect that it is due to subtalar varum and internal tibial torsion, at least from what we can see and what we now without the advantages of an exam and clinical information.  Lets now make this assumption and talk about it from this angle.

Tibial torsion is due to the development of the tibial shaft. It begins in utero, where most of us have tibial varum (due to intrauterine positioning), usually Left sided more than right (because most babies are carried on their back on the Left side of the mother and the Left leg overlies the Right in an externally rotated and abducted position.

At birth, we usually have a 5 degree toe in due to a 30 degree angle between the talar dome and head, which slowly decreases to approximately 18 degrees as we grow into adulthood, leaving us with a 4 degree toe out (still a fairly narrow progression angle). Meanwhile, the tibial plateau and malleoli are parallel at birth and the distal tibia “untwists” externally as we age (at a rate of about 1-1.5 degrees per year) till it reaches an ideal of 22 degrees in adulthood.

Over rotation of the distal tibia (relative to the proximal) results in external tibial torsion with a “toe out” or as it is referred to as, increased progression angle. Under rotation results in internal tibial torsion, or a “toe in”, also referred to as a decreased progression angle.

Some sources say that the development of the talus (angle between the dome and head) is largely responsible for foot position and progression angle. We think that careful measurement (looking at the transmalleolar angle, a topic for another post) reveals which it is, and in our experience, it is usually a combination of both (ie tibial torsion and talar development).

This video is an excellent clinical example of an in toed gait, a negative progression angle.

Ivo and Shawn…The Gait Guys….Yes, we are torsioned (or twisted as some may argue)….straightening out the facts so you don’t have to.

More constructive dialogue on The Cross Over Gait: Q & A Session with a Mid-Distance Coach.

Dear Dr. Allen,

I attended your sessions yesterday at the ITCCCA Clinic, which I appreciated very much.  I am a retired middle/long distance runner who is now getting into coaching.  I have always been fascinated by this kind of research and spotting warnings [things presented at the conference this year ] before they become injuries.  I think that the attention you are bringing to video analysis, form, and SES is the most significant change happening in the sport of running.  Applying this analysis to young runners will help countless numbers of them, both by identifying weaknesses to strengthen and by alerting coaches to an athlete’s propensity for certain overuse injuries. 

As your work gains much deserved attention, I do have a concern with your approach to the “cross-over gait."  I spoke with you briefly about it yesterday, and I have been thinking about it since then.  From my experience and amateur research, it seems as though a distance runner does well to strike both feet along a single line.  Here is a little of my reasoning:

Distance running is largely about efficiency.  While a sprinter gets more power and speed by pushing in a zig zag pattern from foot to foot, that does not mean it is an efficient action.  A distance runner does want some power in his/her stride, but cannot afford to waste any energy like a sprinter can.  I would argue that the difference between a sprinter’s ideal stride and a distance runner’s ideal stride should reflect this. 

It seems logical that a runner’s most efficient push-off point is directly beneath his/her center of gravity.  If we strike the ground to the left or right of this point, some energy goes into sideways motion or adjusting for the asymmetrical force with more glute action.  To your point, this off-center stepping pattern almost certainly yields more power than a straight-line pattern, as the best short-sprinters all use it.  I found this video of Carl Lewis’ beautiful stride demonstrating your point.

However, if you look at the best distance runners in the world, and even middle distance runners, you’ll see much more "cross-over."  The other two videos I list below aren’t great, because they’re in real time, but you can still discern the in-line foot strike of most of the athletes.  These runners may be getting less power out of their glutes, but they’re taking advantage of the gluteus maximus’ natural design to rotate the pelvis forward efficiently.  For most of the race, I’m not convinced that altering that pattern would be productive.
 
I am far less knowledgeable than you in physiology and biomechanics, and I have not performed the necessary research to substantively contradict you, but I write to request that you investigate this issue further.  I may also have misunderstood the nature of your form adjustment work with middle- and long-distance runners; kicking at the end of the race or surging in the middle could very well take more of a sprinter’s form.  The general stride of a distance runner, however, is likely specific to the particular demands of the race and the body’s aerobic limitations. 

I think that coaches should be very careful to adjust a runner’s natural stride unless there is significant evidence supporting the change.  When the evidence is clear, I like that your approach is as deep as possible: finding the root cause of the weakness and working on it gradually.  I fully support your efforts to prevent injuries in this way.  I urge you to continue expanding the body of research and striving to improve the experiences of budding runners.

Thank you for considering my observations.  Please feel free to contact me anytime.

A.

______________________________

Our response:

Dear A.:

I appreciate your inquiry in the most cordial manner, the coaching world is blessed to have attentive and curious coaches like yourself. Great insight comes from great questions like this. 
I certainly do appreciate your concerns.  But your personal opinion needs some backing. I fully respect and understand your thoughts and although they are well thought out, there is nothing i have found in the literature to support it.  Mind you, there is not alot to support mine either however results do have a voice and when we make these changes, even in our mid distance runners, their injuries resolve and do not recur and their times drop.  So, there is some strength to the crossover correction it seems. More research would be nice but no one is doing it so we must base our thinking on some logic as laid out below.

Keep in mind efficiency comes with using each muscle optimally and quite often in
"line running” (crossing over) the gluteus medius and foot do not work correctly. Look at the terrible foot function in the video above. Please watch and read our 2 part series on the blog on Lauren Fleshman(links below). She is fraught with injuries and her hip and foot biomechanics are terrible as we point out in both of those blog posts.  Improving her muscle efficency in using them correctly will improve her overall kinetic chain efficiency, certainly make her less injury prone, and probably make her faster. 
As for putting one’s foot under their body mass,  I challenge your thought merely because when you are on one foot your center of mass is shifted over to the stance leg not directly under your sacrum (watch my 2 part series on youtube “hip biomechanics”,  here I explain the accepted biophysics of the kinetic limb).
The foot should be under the knee and hip, where the body mass has shifted in the single leg position.  The only person who will not shift their mass is one who doesn’t use their gluteus medius to draw the mass over the hip (again, it is in the hip mechanics videos) and that person will likely have hip problems in time because the compressive load on the femoral head is excessively abnormal plus they are often fraught with trochanteric bursitis and chronic ITB issues (let alone knee and foot issues).

Please digest what I have said here and lets keep a constructive and productive dialogue going, nothing I said here was meant to upset you, merely to try to give you my stance.
I am never afraid to have my theories challenged. I am humble enough to know I do not know everything and admit when I am wrong. I want to learn and get smarter so I can help more athletes and coaches become better.  So, if you can refute my dialogue above, particularly with science and research, I am happy to continue this learning experience for us both.  But please watch the videos I have mentioned first so we can base our discussions on solid functional anatomy and biomechanics (save us time, so we can get down to a good dialogue).
So, to this point, although i see your logic, I respectfully must disagree from sheer fact on anatomy, physics of body mass shift, and biomechanics.  I think you will find the 2 brief lectures on hip biomechanics exciting and helpful.
Remember, the swing leg is a pendulum, the most effective pendulum is one that never shifts its center of pivot (energy change),  the cross over gait shifts with every step. A centrated joint is one that pivots freely allowing the attached musculature to function as they were designed.
 I look forward to future constructive dialogue. I would like our relationship to be an asset for us both.

Below are the videos, in logical order, to support my response.

http://thegaitguys.tumblr.com/post/10239421449/dr-shawn-allen-discusses-gait-biomechanics-again

http://thegaitguys.tumblr.com/post/10400372557/in-this-part-2-installment-of-applied-hip-gait

http://thegaitguys.tumblr.com/post/13158702554/the-cross-over-gait-in-a-professional-runner

http://thegaitguys.tumblr.com/post/13298030775/how-a-really-fast-runner-could-potentially-be

http://thegaitguys.tumblr.com/post/13205227823/gait-video-analysis-olympian-carl-lewis-carl

Then of course there is the 3 part crossover gait series we did on August 24th & 25th (you can access our archives by clicking on the clock in the upper right corner of the blog page).

respectfully……. and fully appreciating your passion
shawn and ivo……. The Gait Guys

Foot Strength: Some Clinical Q & A.→

A Few question (and answers) about Foot Problems, from our Blog.

Dr. Ivo Waerlop and Dr. Shawn Allen,

I have had the pleasure of reading much of the content of your website and I have gained many valuable insights into the fascinating world of gait. I have a number of questions that I would love to get your perspective on though. First question: What exercises or techniques do you use to strengthen the intrinsic foot musculature? I gleaned that you are not particularly fond of flexor dominant exercises like towel scrunches so how do you functionally improve the strength, muscular balance and neuromuscular control over those little muscles? Second question: What strategies do you use when treating runners with plantar fasciitis? Would you move them into a less supportive or minimalist shoe or would you bump them up temporarily into a stiffer shoe or use a rigid orthotic?

I would like to also take the time to thank you guys for posting volumes of valuable information on your website. I have found that your website has a remarkable amount of solid, scientifically based information on topics that typically are rife with misinformation when discussed on other websites. Keep up the excellent work and I greatly look forwards to hearing your response to my questions.

Thanks,

JD

____________________

The Gait Guys Response:

JD:

Thanks for the support and the kudos. In answer to your inquiries:

“First question: What exercises or techniques do you use to strengthen the intrinsic foot musculature? I gleaned that you are not particularly fond of flexor dominant exercises like towel scrunches so how do you functionally improve the strength, muscular balance and neuromuscular control over those little muscles?”

Exercises are prescribed very specific to muscle weakness. There are no “swiss army knife” exercises. Each case is on an individual basis, based on physical exam and muscle testing. For the most part, there are really no bad exercises just bad choices for a specific case and poor execution (although one can easily find on YouTube a plethora of ridiculous examples of foolishness worthy of only The Darwin Award).

The small, intrinsic muscles of the foot have many functions, but flexion of the distal toes is not one of them (this is all afforded via the long flexors, FDL). Proprioception from the feet is very important and information from these muscles, as well as the articulations they traverse, provide the brain with much information about the environment, as well as the landscape they are traversing. Increasing proprioception from the feet (through gradual introduction of more minimalistic footwear and going barefoot) is as paramount, if not more important, as increasing strength. Skill, endurance, strength (S.E.S.) in that order (larger diameter, medium diameter and smaller diameter neurons respectively) is the rule for progressing exercise.    S.E.S. is an abbreviation we coined, but it is based purely on neurophysiology principles …  all of our information is science based. You will find no ‘internet forum’ assumptions here, as  you have so accurately gleaned. As for an example of some of our exercises, we are currently trying to find time to create some new videos of our current exercise protocols. As we mentioned however, it is a difficult projected since each case has different needs and differing orders of protocol. None the less, here is an “oldie but a goodie” from two years ago. Click here.

“Second question: What strategies do you use when treating runners with plantar fasciitis? Would you move them into a less supportive or minimalist shoe or would you bump them up temporarily into a stiffer shoe or use a rigid orthotic?”

A: The causes of plantar fascitis are multifactorial, but I think we all agree that overpronation of the rearfoot, midfoot, forefoot (or a combination) all play a frequent role. Following that assumption as a possible cause, the question is, What is causing the overpronation? Is it due to muscular incompetence? Is it due to loss of ankle rocker? Is it due to a loss of hip extension? Is it due to….. (fill in the blank).

The treatment depends on the etiology. As we just eluded, the cause is not always a foot issue, there can be top-down kinetic chain causes. Progressing them to more minimalistic footwear is a great idea (provided they have earned their right to be in it and have muscular competency and appropriate foot structure). The problem is that not everyone does have the necessary structure to drop into minimalism, some never and some need help with a logical progression.  Modalities like acupuncture, ultrasound and EMS, to reduce inflammation certainly help in pain management and can expedite the healing process. At times, if the case calls for it, using an orthotic to temporarily give them the mechanics they do not have, and relieve some of the tension of the fascia is appropriate. Sometimes the orthotic makes things worse (too much support, not enough support). Sometimes, albeit rare, the orthotic is suspect as the causal mechanism.  The root cause needs to be identified and then the appropriate therapy can be initiated.

We get questions like these all the time. They are great questions but they are often fraught with so many open ended subsequent questions and parameters that we often feel our answers are never good enough.  But, if solving things like plantar fascitis were easy in every case, we would not see clients in our practices who arrive with a bag of orthotics, a long  history of therapy, and multiple failed interventions. There are no easy answers or magic bullets. If there were, there would be no need for The Gait Guys.

Providing answers to difficult questions.

Ivo and Shawn

Robotic Gait Retraining→

People who have had a stroke and have difficulty walking often develop improved gaits when they add robotic assistance systems to conventional rehabilitation. A study funded by the Italian Ministry of Health and Santa Lucia Foundation compared the walks of 48 severely impaired stroke survivors. Half the group received conventional rehabilitation and the other half received conventional rehab plus robotic gait training. The study, published in Stroke: Journal of the American Heart Association, showed the added robotic gait training worked for people with severe impairments, but did not significantly help patients with higher mobility.

The robotic devices are electromechanical platforms attached to a patient’s feet. A physical therapist sets progressive bearing weights and walking paces and measures how the patient is doing.

So, the question is WHY? The simple answer is that we are much smarter than a computer or device. The brain makes millions of calculations per second to perform the concert we call gait. A computer cannot approximate all the variables; only the ones that are programmed. The folks with more mobility (less morbidity) were “smarter” and more than likely, the computer slowed them down. The less fortunate ones needed more help.

The Gait Guys: sifting through the literature and bringing you the highlights.

Yup. We thought we had seen it all. Make sure to wear your evening formal neoprene. Coming soon: Underwater Gait Analysis.

Have a great Friday

Ivo and Shawn

photo credit: xcitefun.net

Foot Landing Mechanics→

Foot Landing Mechanics, Part 1 of 2

This dialogue is likely going to open up a storm of controversy and dialogue,  …  good !

In a very recent article in LER (Lower Extremity Review) Katie Bell wrote a nice article about foot “Orthotics and Landing Mechanics”.  Her article, and the research she referenced, suggests foot orthoses can affect frontal and transverse plane motion in proximal joints during landing from a jump. It was postulated from the research that orthotics could therefore help reduce the risk of anterior cruciate ligament injury, particularly in females.

In the May issue of the Journal of Applied Biomechanics, it was determined that gender differences as well as foot orthotics affect frontal plane hip motion during landing after a vertical jump. This is really nothing new or mindblowing. Heck, putting a pebble in someone’s shoe will change their landing and gait mechanics, but it is nice to see more talk in the research. Any observant and educated clinician can see that from a vertical jump, if the client does not have enough gluteal function to slow the internal spin of the limb (the glute is a powerful external rotator and thus also a powerful eccentric controller of internal rotation) that the knee will valgus medially. Furthermore, if the foot is not strong and stable, the downward weight will collapse (to varying degrees) the arch and thus also drag the knee medial. Thus, it is critical to discuss both components of knee stability, meniscal issues and ACL issues.  Any study omitting observations of gluteal function and only commenting on the effect and merits of the orthotic to control the knee is only telling half the story. Admittedly, research articles can look at isolated issues like this study did if it pleases them, but it is our mission not to let tunnel visioned biases enter into things. Tunnel vision leads to assumptions that some problems have simple solutions. Our clients get evaluated through the entire kinetic chain when looking at foot and knee issues. Heck, even arm swing and opposite leg swing impact the function of the stance phase knee (look at the mechanics behind the Abductory Twist for example or read our blog posts from early December on arm swing impacting lower limb mechanics).

We are not dismissing these research findings however, yes orthotics can help reduce risk at the ACL …  IN SOME CLIENTS, but it could enable risk in others if the correction at the foot is not the proper intervention. What if the entire risk scenario is from a dysfunctional hip ? Now you have changed the foot’s dynamic compensation for the hip dysfunction. Couldn’t that increase ACL risk ? You bet it can. Thankfully, as we read on, the LER article quoted Walter Jenkins PT, DHS, associate professor and chair of ECU’s Department of Physical Therapy. “Dysfunctional hip motion is commonly observed in patients with knee pathology.” It was nice to see that, sadly we felt the articles angle was to mediate the dysfunctional hip motion via correction at the bottom. We all should be reminded that the organism must be evaluated and thus treated as a whole.

Modifying dysfunctional hip motion locally, if there are local issues, can reduce knee risk and may modify the necessity or degree of intervention at the foot level. So, landing mechanics are about the foot, the hip and the knee mechanics pending the mechanical forces from those other two joints above and below. Merely adding an orthotic is going to change the landing mechanics but, as we mentioned earlier, putting a pebble in someone’s shoe is going to change their foot dynamics and how they load, so is a pebble a reasonable answer too ? The question is are they the mechanics you want for your client ? Are the foot changes with an orthotic locally prostituting the normal hip mechanics ? Orthotics are not the Holy Grail. In some cases they are the Devil’s pitchfork. It takes a very educated and skilled practitioner to know the difference.

The Journal of Applied Biomechanics researchers analyzed the 3D motion of the lower extremities in 36 study participants (18 women, 18 men) during a vertical jump with and without prefabricated foot orthoses. In the women researchers found significantly less hip adduction with foot orthoses compared with no orthoses (p< .05). The men showed no differences between foot orthoses conditions. So, does this mean that the women need orthotics ? Or does it mean that their Q angle is a participant ? Does the study necessarily mean that the answer to these ladies issues is an orthotic ? Or does it mean that they could need more hip stability and loading skills to dampen internal limb rotation and valgus knee drift ? The article (thankfully) does suggest that the apparent gender-specific proximal reactions to foot orthoses during landing may be related to kinematic landing strategies which is a good observation, but do not think that orthoses are the take away answer from this article.

The study also showed things we have talked about previously, that being that men actually land in knee varus and use hip adduction and knee valgus as a strategy to accelerate during the jump after the deceleration phase of landing. Where as women tend to land more valgus and but seem to be more challenged to control this force.  But for an article to suggest that “A foot orthotic may be a simple solution—and quicker than neuromuscular retraining—to control motion.” is a scary conclusion. They go on to say “Ultimately, orthoses may be an excellent adjunct to a neuromuscular training program.” we agree with in part.

Nothing is more valuable than a limb that can support and control itself with optimal neuromuscular function. If you do not have it, take time away from risky sport challenges until you have achieved it. Do not take a short cut and depend on an external device, unless of course the client has a fixed anatomical compensation or issues (ie. forefoot varus) OR you are using it as a training aid, to TEMPORARILY offer mechanics that the client does not have, working toward helping them to eventually get them. In those cases, a device is often helpful and recommended, but IT IS IMPERATIVE  to retrain neuromuscular protective reflexes and function.

We are going to do a Part 2 on this very important topic this weekend. If you are in a sport where you are jumping and landing you absolutely need to read Part 2. We will be offering up a hopeful epiphany for you on why so many people sprain their ankles. It is a landing mechanics problem…… not discussed anywhere else in the research or on the web….. until now !

We are The Gait Guys …. two guys who always finding themselves standing outside some strange box everybody is talking about.

Have a good Friday everyone !

Shawn and Ivo

A 30 second workout has similar results as a 90 minute one ?→

McMaster University (Canada) studies on the effectiveness of high intensity interval workouts. 

Sprint Results Set the Stage

The 2005 study and others (links provided above), published in the Journal of Applied Physiology and , showed that three to seven all-out sprints on a stationary bicycle (250% of VO2 max), 30-seconds each, with four-minute rest periods, six times over two weeks, are as effective as 90 to 120 minutes of cycling at moderate intensity (65% of VO2 max) six times over two weeks. Both workouts improved endurance capacity by almost 100%, increasing time to fatigue at 80% effort from 26 minutes to 51 minutes. In short, about 15 minutes of hard sprints spread over two weeks produced the same results as nine to 12 hours of moderate intensity effort.

Both the sprinters and the traditional riders showed a substantial increase in citrate synthase, a mitochondrial enzyme that indicates the power to use oxygen, along with increased glycogen (muscle sugar) content. Neither group, however, showed a change in maximum oxygen uptake (VO2 Max, or the ability to utilize oxygen per kg of body weight in liters per minute; it can be approximated to % max heart rate with the formula %MHR = 0.64 × %VO2max + 37) or anaerobic work capacity (ability to produce lactate, a byproduct of anaerobic metabolism).

The interesting thing about this study, is that the high intensity exercise group should have produced more anaerobic work (ie more lactate) and probably did BUT were able to clear it faster because of the short duration of the exercise. Remember that the 1st few seconds of the 30 second sprint would have been using creatine phosphate stores, before tapping into the glycogen stores.

The lower intensity exercise at 65% VO2 Max works predominantly the aerobic system (incidently, 65% of VO2 Max is probably a “moderate exercise” and is probably less demanding); thus these folks would be better able to recycle lactic acid, should the levels rise to levels requiring it. Changes in VO2Max would be able to be changed much less (3-5%) in trained individuals than untrained (up to 20%), so the findings are not that surprising.

The bottom line is that high intensity training offers some gains that are similar to traditional aerobic training with less time, and should probably be included in your training regimen.

Shawn and Ivo……..Striving to increase your knowledge base more efficiently

Does stretching make a difference? Does it enhance or inhibit performance?

Today’s discussion is not fiction or merely our opinion, you should know by now that The Gait Guys are not about presenting misinformation, we are about presenting the facts. Today’s dialogue is based on hard, solid, peer-reviewed research and neurophysiology principles. If you feel you disagree with us, please present your research papers so we can begin a productive dialogue amongst us.

Join Dr Ivo in this weeks neuromechanics to explore these questions and more. Also check out past episodes of neuromechanics weekly on our Youtube channel: “The Gait Guys”

Have a great day!

A few minutes in our Brains.

We were over at a book store on the weekend and picked up a book called Incognito written by neuroscientist David Eagleman.

The gist of the book was that the majority of brain activity is largely subconscious. That the brain is continuously processing information and working algorithms to questions and problems that we have inquired about either consciously or subconsciously. A conscious example might be pondering which new computer to buy, factoring in price, model, manufacturer, specs, hard drive size, peripherals desired, etc. Over a period of minutes, hours or days you bounce around the issues until you rationalize a best decision for your needs and wallet. On the other end, a subconscious example might be learning a new motor skill in your gait pattern. For example perhaps, a pathologic pattern is the one being learned. In one case the brain may be subconsciously learning to reduce gluteus medius muscle in an attempt reduce hip joint compression forces and thus hip pain due to a degenerative joint cartilage surface (see Dr. Allen’s recent video, Applied Hip Gait Biomechanics, Sept 15). In this scenario the brain was working out the algorithm to solve for the pain. The brain is continuously subconsciously processing to solve these problems, it is always working in the background, in sleep or in a wakeful state. We have all had these epiphany moments where the solution to a problem comes to you seemingly out of the blue. However, it is not the case. The brain had been at it for some time.

Eagleman describes the conscious brain as a CEO who is handed a final product that has been worked on by hundreds of employees for weeks, those employees being the subconscious brain parts. The CEO is the last to know, they only get to see the end success of hundreds of hours of work by the employees, and they often take full credit because they are the CEO afterall. It is a long process to achieve solutions to complicated problems. Afterall, do you really think Steve Jobs made the iPad all by himself ? Some might.

Where are we going with this ?

Unconscious incompetence: you do not know the right foot has turned out during gait.

Conscious Incompetence : someone has brought it to your attention.

Conscious Competence: you find a reasonable motor pattern to turn the foot in, but you must stay conscious of this pattern for the correction to be maintained.

Unconscious Competence: eventually unknowingly achieving the foot alignment correction. Give the brain the correct information … then give it time and the correct supportive exercise and let the brain figure it out. It will bring that foot inline eventually as long as there are not other impeding factors. The key is making sure that the pattern you teach your client , or that you institute yourself, is not a compensation. That’s the hard part ! You have to know what is right before you know what is wrong. Pick the wrong pattern and you find yourself down a fork in the road that is full of potholes and problems. Don’t guess. See someone who KNOWS. We had a guy fly in to see us yesterday and this was exactly the case. Therapy has been prescribed in-part off of a video gait analysis and incorrect physical evaluation. You can’t guess at this stuff. You gotta study!

Coming directly from our temporal lobes, we are…The Gait Guys

The Gait Guys. Two weeks ago you talked about a dog’s gait, now cockroaches ? Yup, watching nature at work fosters much insight into gait principles.

Biomimetics, also known as Bionics, is another name for engineering systems that copy principles found in nature.

If you are real gait geeks you have probably seen some of the cool robots inspired after  the insect world. Many of these robots are called hexapods (six legged robots), just like insects. With 6 legs alternating limbs on opposite sides of their exoskeleton (see diagram above) it can provide an inherently stable tripod mechanism that is effective and efficient in when it comes to locomotion. Insects are great models because they have an extremely stable and efficient model of locomotion through something called a tripod gait. We have a video link demonstrating this a little further down.  At any time, cockroaches for example have 3 limbs in contact with a surface.   This tripod structure makes them very stable and mobile.

The stability of the hexapod comes from its ability to establish this gait pattern in which at least three legs are on the ground at any time. Just like the 3 legs of a tripod, when they are firmly planted, the platform is very stable.  You will notice from our year of blogging that we continue to talk about the foot tripod, consisting of stability points at the head of the 1st and 5th metatarsals and the heel. These 3 points of stability of the foot are necessary to make up the longitudinal and transverse arches of the foot. Without the ability to anchor these 3 points effectively on the ground the foot becomes unstable and compromised. Hence why we see bunions, hallux valgus, metatarsalgia, abnormal plantar callus patterns as well as various presentations of foot pain in feet that have lost the tripod ability. The key however is then to place, and maintain, the body mass within the confines or borders of the triangle made by joining these 3 tripod points (see the colored area in the diagram above). In humans, if your body mass deviates towards the outside of the tripod, in other words approaching or violating an imaginary line drawn from your 5th metatarsal to the heel (ie. approaching supination), you tip the foot laterally and begin to compromise the anchoring of the medial foot tripod (under the 1st metatarsal) and risk formation of bunions and hallux valgus among other functional pathologies of excessive or constant supination. On the other hand, If your body mass approaches or exceeds the arbitrary medial border of the triangle delineated by a line drawn from the head of the metatarsal to the heel  you are considered a possible hyperpronator and all of the functional pathologies that accompany it (ie. plantar fasciitis etc).  Bottom line … a tripod is stable, just stay withing the colored lines. Note in this cool video (click here) how clear the 3 pronged tripod engages and how the body mass of the robot stays within the borders of the tripod limbs. In other words, keep your ankle and more specifically the force vector, over your foot tripod (the colored lines),  and most pathology issues will be absent. The closer you get to tipping the tripod, the closer  you are getting to developing biomechanical pathology in the lower limb.  Put another way, by increasing weaknesses in the foot intrinsic and extrinsic muscles and possibly the other stabilizers of the lower limb and pelvis, the closer your body mass will fall towards the edges/limits of the tripod triangle borders. And the closer you are to the risk of gait pathology and pain.

( In the diagram above, for you hexapod insect loving gait fans, the most basic hexapod walking pattern is called the alternating tripod gait. Taken from this site, in this gait, the six legs are treated in two groups of three. Either group of three is a tripod formed by the front and rear legs of one side, and the middle leg of the opposite side. The three component legs of each tripod are moved as a unit. As one tripod is lifted, the other tripod pushes forward. In this gait it can be helpful to think of each tripod as a foot and compare it to your own bipedal walking where as one foot is lifted the other foot pushes forward.)

And you still thought we were just your average Gait Guys, didn’t you ?! If it walks, trots, gallops, canters, jumps, runs, jogs or whatever….. we are on top of it.  Yes, even if that means cockroaches ! We are here to stay gang, in 2012 we will begin to execute our plan for intergalactic dominance, gait related only of course.

Nerd Shawn & Geek Ivo

A Coach with Anterior knee pain:  About as common a problem as finding dirt on a child.

We get emails like this all the time. Here is one from a coach with a problem.

Hi Gait Guys,

I was just found your blog visiting one of the running sites I like coachjayjohnson.com. I’m a high school xc/track coach and a former runner myself. I say former because I dug a nice hole in my cartilage in the lateral trochlear groove about 4 years ago from running. This actually happened 3 months after I stopped wearing the custom orthotics i had been wearing for about 8 years. What a mistake that was, but the biggest mistake might have been getting them in the first place.

Anyways, 3 months ago I had a procedure done to regrow the cartilage. this was done at the stone clinic in San Francisco. The doctor said I should wait a year before I attempt to run again. I’m fine with that but sometime next year once my knee is feeling good enough I’d like to come see you guys before I start running again so that you can help analyze everything and get me out there running again with good form and in the correct shoes etc. Where are you guys located? Also, are you going to come out with some new DVDs?

Thanks,
(name removed)

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What The Gait Guys have to say …

Dear Coach:

(Links in our discussion have been embedded for you and other readers and we have included a picture above so everyone else will know where your problem was.)

Anterior knee pain in runners is about as common a problem as finding dirt on a child. You have described the all to common, osteochondral defect. IT is a defect of bone and cartilage quite often from blunt or repetitive trauma.

Knee joint anterior malalignment is multivariably associated with patellofemoral osteoarthritis (study). Alignment issues at the knee can be driven by variations of the optimal anatomy (versions and torsions, see a post on this from ~3 weeks ago) but in our opinion they are often driven from other factors most notably improper biomechanics driven by muscle weaknesses-tighness. However, other factors can come into play to complicate the scenario, such as poorly selected footwear for a foot type. Alignment at the knee is subservient to the mechanics at the hip and foot. Both the hip and foot are multiaxial  joints, whereas the knee in its healthy state and most basic description, a sagittal hinge joint (sure, miniscule rotation). When the hip or foot are prostituted and some of the availability of their normal motion is lost or changed (as is possibly the case of an orthotic as you eluded to, however in the hands of a skilled practictioner the orthotic can help positively restore compromised function, if they understand and assess whole limb kinetic function) the knee joint can often find itself in the middle of altered biomechanical force streams. This all to often can lead to anterior knee pain, compromised function of the patellofemoral joint.  This, as in your suspected case, can lead to abnormal cartilage wear at the interface of the two bones.

In one article it was proposed that physical activity may modify the association between joint incongruity and cartilage loss, and can be further affected by subject characteristics such as gender. It must be part of the thought process that rather than it being the activity, is more likely to suspect altered biomechanics during said activity as being the culprit.  Understanding these complex interactions will help optimize strategies to maintain patellofemoral joint health. However, this study found that for every one-degree increase in the proximal trochlear groove angle at baseline, there was an associated 1.12 mm  increase in the annual rate of patella cartilage volume loss. This brings a person’s given anatomy, perhaps suboptimal anatomy, into play and thus adds one’s risk factors. There was a trend for this effect to occur for males, as well as people participating in vigorous physical activity. Males who exercised vigorously were more adversely affected.

In conclusion, this study showed that in vivo engineered cartilage was remodeled when implanted; however, its extent to maturity varied with cultivation period. The results showed that the more matured the engineered cartilage was, the better repaired the osteochondral defect was, highlighting the importance of the in vitro cultivation period.

There are many surgical interventions out there for anterior knee pain, such as tuberosity transfers, retinacular releases, injections, and God forbid patellectomies among others (yes, we have clients who decades ago had this done, imagine that! Thankfully this radical move is no longer done !). Most people simply need a well versed biomechanist who understands the whole kinetic chain, understands the force streams, can assess for the limitations and reduce them to restore the previous normal mechanics.  Sadly, sometimes interventions are not optimal or precise and folks end up like you coach. And then surgery is your only option.  Thanks for sharing your story and reaching out to us. Sharing your anonymous story may help others avoid your painful journey. We would be happy to see you, we are getting more and more letters like yours both here in the home land and internationally. Hopefully, our mission will help reduce these problems, if at least just a little. (PS: yes, our 3 part Shoe Fit / Biomechanics & Functional Anatomy DVD and online program should launch in February. Information about the launch will be right about the time phase 2 of the website will lauch www.thegaitguys.com).

Best to you.

Shawn and Ivo, The Gait Guys

Genu valgum in kids: What you need to know

We have all seen this. The kid with the awful “knock knees”.  It is a Latin word “which means “bent” or “knock kneed”. It appears to have 1^st been used in 1884.

This condition, where the Q angle angle exceeds 15 degrees, usually presents maximally at age 3 and should resolve by age 9. It is usually physiologic in development due to obliquity of the femur, when the medial condyle is lower than the lateral. Normal development and weight bearing lead to an overgrowth of the medial condyle of the femur. This, combined with varying development of the medial and lateral epiphysies of the tibial plateau leads to the valgus development. Gradually, with increased weight bearing, the lateral femoral condyle (and thus the tibial epiphysis) bear more weight and this appears to slow, and eventually reverse the valgum.

Normal knee angulation usually progresses from 10-15 degrees varus at birth to a maximal valgus angle of 10-15 degrees  at 3-3.5 years (see picture).  The valgus usually decreases to an adult angle of 5-7 degrees.  Remember that in women, the Q angle should be less than 22 degrees with the knee in extension and in men, less than 18 degrees. It is measured by measuring the angle between the line drawn from the ASIS to the center of the patella and one from the center of the patella through the tibial tuberosty, while the leg is extended.

Further evaluation of a child is probably indicated if:

• The angle is greater than 2 standard devaitions for their age (see chart) 
• If their height is > 25^th percentile 
• If it is increasing in severity 
• If it is developing asymmetrically

Management is by serial measurement of the intermalleolar distance (the distance between ankles when the child’s knee are placed together) to document gradual spontaneous resolution (hopefully). If physiologic genu valgum persists beyond 7-8 years of age, an orthopaedic referral would be indicated but certainly intervention with attempts at corrective exercises and gait therapy should be employed. Persistence in the adult can cause a myriad of gait, foot, patello femoral and hip disorders, and that is the topic on another post.

Promotion of good foot biomechanics through the use of minimally supportive shoes, encouraging walking on sand (time to take that trip to the beach!), walking on uneven surfaces (like rocks, dirt and gravel), gentle massage (to promote muscle facilitation for those muscles which test weak (origin/insertion work) and circulation), gait therapeutic exercises and acupuncture when indicated, can all be helpful.

Ivo and Shawn…  The Gait Guys…Promoting foot and gait literacy for everyone.

We are not generally fans of Nike, but they do have some cool commercials. Here is one of our favs of cyborg parkour.

Have a great Friday

Ivo & Shawn

Gait ischemia? Blood flow affecting performance.→

Research evidence that gait is altered in ischemia (inadequate blood supply) environments.

Know someone with diabetes, peripheral artery disease or spinal stenosis (especially the vascular variety) ?

This study’s findings indicate increased “noise” and irregularity of gait variability patterns post-ischemia. In young healthy individuals who do not have neuromuscular impairments, significant gait alterations are present during walking after a period of interruption of blood flow. This could be from something as simple as muscular compression, or something more serious.     

We just wanted to wet  your appetite for some stuff like this coming your way, from us, The Gait Guys.  If this does not make you think about compressive socks and stockings, you need a second cup of coffee this morning !

Shawn and Ivo

                                                                                                                                                                                             

Gait variability patterns are altered in healthy young individuals during the acute reperfusion phase of ischemia-reperfusion.

J Surg Res. 2010 Nov;164(1):6-12. Epub 2010 May 18. Myers SA, Stergiou N, Pipinos II, Johanning JM.

Source

Nebraska Biomechanics Core Facility, University of Nebraska at Omaha, Omaha, Nebraska 68198-3280, USA.

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Gait: Does Minimizing center of mass vertical movement change your metabolic cost ?→

Research article: Minimizing center of mass vertical movement increases metabolic cost in walking.

Ortega JD, Farley CT. Locomotion Laboratory, Dept. of Integrative Physiology, University of Colorado, Boulder, CO 80309-0354, USA. ortegajd@colorado.edu

J Appl Physiol. 2005 Dec;99(6):2099-107. Epub 2005 Jul 28.

So what is this article’s bottom line ? The premise of the research article was to look at the relationship between vertical movement in gait and its metabolic cost by having human subjects walk normally and with minimal center of mass vertical movement (“flat-trajectory walking”). What the article found was that it costs more to move with a flat trajectory. In other words, dampening the normal vertical oscillations is not a good thing.  But we have some concerns.

Not that we have a major problem with this study, but we do have two concerns we think should have been brought up problem.

1- Were these folks in the study assessed for biomechanical compensations ? You have read our discussions on impaired ankle rocker. And one of the major flaws of impaired ankle rocker is the premature heel rise gait, where the person can adopt a rather boucey vertical gait, almost appearing to walk on the ball of their foot. These folks have a very vertical gait.

2- Since the study concluded that the less vertical trajectory gait was seen to be far less metabolically efficient it is a well founded question to ask more about the strategy they employed. In the study they merely added more joint flexion to dampen the vertical trajectory.  But, had they been coached to use the core to minimize vertical trajectory and utilize the energy moving forward while still obtaining some of the normal biomechanical components, some of which take advantage of limb extension, would the study have found the same thing ?  Once again we find a good study but one that bodes more questions than it answers, such as, did the researchers really know enough about gait biomechanics to give good cues?  Furthermore, how much vertical is too much ? How much dampening is too much ?

  We still appreciate the study and its findings, but you cannot trust everything you read, at least not without reading the fine print.  Here is the full abstract below. Read it yourself and if you are curious enough, get the full study for yourself.

Shawn and Ivo…….keeping you on the edge of the research.

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Journal Abstract

A human walker vaults up and over each stance limb like an inverted pendulum. This similarity suggests that the vertical motion of a walker’s center of mass reduces metabolic cost by providing a mechanism for pendulum-like mechanical energy exchange. Alternatively, some researchers have hypothesized that minimizing vertical movements of the center of mass during walking minimizes the metabolic cost, and this view remains prevalent in clinical gait analysis. We examined the relationship between vertical movement and metabolic cost by having human subjects walk normally and with minimal center of mass vertical movement (“flat-trajectory walking”). In flat-trajectory walking, subjects reduced center of mass vertical displacement by an average of 69% (P = 0.0001) but consumed approximately twice as much metabolic energy over a range of speeds (0.7-1.8 m/s) (P = 0.0001). In flat-trajectory walking, passive pendulum-like mechanical energy exchange provided only a small portion of the energy required to accelerate the center of mass because gravitational potential energy fluctuated minimally. Thus, despite the smaller vertical movements in flat-trajectory walking, the net external mechanical work needed to move the center of mass was similar in both types of walking (P = 0.73). Subjects walked with more flexed stance limbs in flat-trajectory walking (P < 0.001), and the resultant increase in stance limb force generation likely helped cause the doubling in metabolic cost compared with normal walking. Regardless of the cause, these findings clearly demonstrate that human walkers consume substantially more metabolic energy when they minimize vertical motion.

You have heard us talk about weakness (short weak and tight weak) muscles all the time on Youtube: The Gait Guys; now here is the neurology behind it. Think about this concept the next time you see a gait compensation and think of the muscles (agonists/antagonists) involved.

On and on goes the barefoot debate. 

There is no single right answer, so use your head.

article link, click here

We have been saying what this article talks about all along, even years before the Vibram 5’s hit the market, back when Vibram came to us to ask us for our thoughts on the early versions.  You will see our soapbox rant on this topic over and over again in our blog posts and it is the modus operandi behind our new 2012 Shoe Fit program that will likely launch February 1st in several forms for several professions to meet everyone’s needs.

That modus operandi being that not everyone has a foot type, anatomy or biomechanics to get into minimalist shoes, without a possible cost that is.

In this nicely written article by Cynthia Billhartz Gregorian “Barefoot running: Sales grow, but so does debate about benefits, safety” at the link above she lightly covers some of the aspects of the debate.  We have read just about every piece that has come out on the barefoot-minimalist trend. Sadly, some of the blogs are mere opinion and it is rare that the honest truth comes out.  That truth being our mention above that some folks just do not have the skill, endurance, strength or anatomy to delve into footwear that does not support or protect their physical limitations.  Lets be honest, at 5'9’’ I have to come to the realization that no matter how much i practice to be in the NBA I am not going to make it. I just do not have the physical anatomy to be an NBA star.  And some people, no matter how much they want to run barefoot or minimalist, just do not have the anatomy to allow it. Someone with a history of foot pain who has a rigid forefoot varus really is not going to do well in minimalist shoes. There are articles written out there that just tell people to bite the bullet and go 100% into their new minimalist shoes, into the natural way they were supposed to run from the very start and force the body to adapt, that the new form they adopt will take care of any problems. Well, in our experienced and educated opinion, that is just not smart. Someone who has a shortened posterior compartment (calf-achilles) after being in heel shoes for years is going to have several flaws biomechanically going to minimalist shoes right off the bat. One example, just one for now, is that the person is going to have premature heel rise and thus premature forefoot loading response around a compromised ankle rocker mechanism. And there are many others of course.

Here is the bottom line as we see it. No shoe company is going to run a commercial or add on their product with the warnings on the cover or in the fine print. We are not talking about cigarettes here.  Admitting that some people should not be in their product would be admitting that the product has limitations and risks.  What kind of advertising add would that be ? Besides, admitting to limitations or mentioning warnings is a mere step away from liability cases.  We are pretty sure of this, after all, look what happened to the Shape Up Shoe in the courts.

Here is what we say to the naysayers, look at the research and use logic.  If you are new to the game, leave the extremist blog sites for those that are looking for radical opinions. Because we do not have any openings in our clinics for the next several weeks if you throw caution to the wind.

Good running to you all in 2012, use your head, for the sake of your feet.

Shawn and Ivo

Ataxic gait?

We hope you have begun the new year in a NON ATAXIC manner. Lets look at the origin of the word:

Ataxia: Greek, from a or without + tassein to put in order or “without order”. Ataxia is truly gait without order, and we will see why momentarily. The term was coined in 1670. Every September 25th is International Ataxia Awareness Day. Mark THAT ONE on your calendars!

Ataxia an inability to coordinate voluntary muscular movements that is symptomatic of some nervous system disorders and injuries and not due to muscle weakness.

It is a lack of afferent information either GETTING TO the CNS, BEING PROCESSED BY the CNS, or OUTPUT FROM the CNS. We can still hear Dr Carrick saying “where is the longitudinal level of the lesion? Is it at the receptor, the effector, the peripheral nerve, the spinal cord, the brain stem, the thalamus, the cerebellum or cerebrum?” This mantra, still rings true many years later, as it gives us the afferent pathway to the brain and higher centers of the CNS.

Ataxic gait, not to be considered synonymous with Fredreich’s Ataxia (the genetic disorder described in the 1860’s, related to spinal cord and cerebellar degeneration), can be due to any number of causes which affect processing of afferent information. One too many Tequila’s (100% agave of course), barbituates, joint pathomechanics, diseases affecting receptors (like syphilis or leprosy), diabetes and other forms of peripheral neuropathy, spinal cord injury or disease are only a few of the causes. Virtually anything that can affect the afferent processing or efferent arc of the processing of proprioceptive information.

The large amplitude corrective movements are clues to the CNS that something is awry and are a necessary component of the compensation. Here , you truly are seeing the result of the compensation.

The video offers a simplified explanation and nice clinical example of an ataxic gait. If you don’t believe it, try some field research (or perhaps you already have) with the ethanol of your choice and see for yourself. Of course, some of THAT ataxia comes from changes in specific gravity of the endolymph in your inner year, but that is the subject of another post.

Ivo and Shawn. The Gait Guys…New and Improved for 2012