Shoes really do make the man….
Have a great Friday!
Ivo and Shawn
Some thoughts on gait and foot pronation…
It is our perception that alot lot of folks seem to be on a mission to eliminate pronation, calling it the scourge of humanity and source of human ailment. While we agree that overpronation causes biomechanical faults in the lower kinetic chain, so does under pronation, and some pronation is necessary and required for normal locomotion. Today we would like to deepen your understanding and appreciation of pronation and it’s potential impact on the foot and lower limb. Today’s post will seem pretty technical for some readers. But it is merely a language issue, one that if worked at will in time become second nature. This is language that we are putting into our Shoe Fit DVD 3 part program, and language that we used at our program launch in Austin TX last week. So if you are thinking this stuff is too difficult, you will be shocked that in a few months many shoe stores around the country will have staff that will be familiar with these terms and biomechanics. Shoe stores that will be able to communicate with doctors and therapists on a common level, because that is what is necessary to improve shoe fit and client outcomes.
When most people think of pronation, they think of midfoot pronation, or pronation about the subtalar or transverse tarsal joints. In lay terms this means collapse through the arch of the foot. Pronation can actually occur about any articulation or bone, but with respect to the foot, we like to think of rearfoot (ie. talo-calcaneal), midfoot (talo-navicular) and forefoot (transverse tarsal) pronation.
Pronation, with respect to the foot, is globally defined as a combination of eversion, abduction and dorsiflexion which results in flattening of the main arch (aka. plantar vault) encompassing the medial and lateral longitudinal arches. In a normal gait cycle, this begins at initial contact (heel strike) and terminates at midstance, lasting no more than 25% of the gait cycle.
In a perfect biomechanical world, shortly following initial contact with the ground, the calcaneus should evert 4-8 degrees because the body of the calcaneus is lateral to the longitudinal axis of the tibia. This results in plantar flexion, adduction and eversion of the talus on the calcaneus, as it slides anteriorly. At this point, there should be dorsiflexion of the transverse tarsal (calcaneo-cuboid and talo-navicular joints). Due to the tight fit of the ankle mortise and its unique shape, the tibia rotates internally (medially). This translates up the kinetic chain and causes internal rotation of the femur, which causes subsequent nutation (anterior tilt) of the pelvis (see picture above) and extension of the lumbar spine. This should all occur in the lower kinetic chain through the 1st half of stance phase. The sequence should reverse after the midpoint of midstance, causing supination and creating a rigid lever for forward propulsion. So in summary, what we have said here is that when the foot hits the ground there is a process of unlocking of the foot structures to allow the foot to splay and flatten to a degree for shock absorption and adaptation to variable surfaces. And when this splay and flattening (pronation) occurs, the leg spins inwards to allow other normal biomechanical events to occur higher up in the kinetic chain.
Pronation, along with knee and hip flexion, allow for shock absorption throughout the 1st half of stance phase. Pronation allows for the calcaneo-cuboid and talo-navicular joint axes to be parallel making the foot into a mobile adaptor so it can contour to irregular surfaces. Problems seem to arise when the foot either under pronates (7 degrees rearfoot valgus results in internal tibial rotation), or over pronates (> 8 degrees or remains in pronation for greater than 50% of stance phase) resulting in poor shock absorption.
The consequence of under or over pronation ultimately means other articulations, including the spine, will have to attenuate more shock. Over time, this may lead to articular cartilage degeneration or ligamentous laxity due to repetitive stresses.
What about asymmetrical pronation? It is rare that people over or under pronate the same amount on each side. Excess midfoot pronation on the right causes more internal rotation at the right knee, and an increased valgus stress at that joint . This puts the quadriceps at a mechanical disadvantage and stretches the hip adductor group, often making them stretch weak, and shortens the hip abductors, especially the gluteus medius, which often becomes short weak. Frequently the IT Band will shorten in this scenario. The right foot, since it is now a poor lever, will often be externally rotated and toes will claw, because the center of gravity has moved medially and they are trying to make that limb stable to bear weight on so they can progress forward. They will often toe off from the inside of the great toe (as is often evidenced by a pinch callus medially ) and this medial foot tripod challenge can lead to factors causing bunion formation. The medial rotation of the lower leg (relative, because of the externally rotated foot) causes internal rotation of the thigh and anterior nutation (tipping) of the pelvis on that side, both which now put the gluteus maximus at a mechanical disadvantage thus limiting hip extension on that side. Now the extension has to occur to somewhere, so it often occurs in the lumbar spine, along with rotation and lateral bending to that side, increasing compression on the right spinal facet joints. From a neurological perspective, the vestibular system now kicks in to level the head, the result being contraction of the left paraspinal muscles. Arm swing usually increases on the contralateral side to assist in propulsion forward. What effect do you think THAT has on spinal mechanics over 10 thousand steps a day? What effect are we having on the nervous system and what neuroplastic changes are occurring?
Having both feet planted on solid ground, or rather having both feet planted solidly on the ground should concern you. As you can see, knowing about pronation and its effects on the entire kinetic chain is paramount. The effects reach far beyond the foot and can often be the root of recurrent biomechanical faults in the human frame. Think about this next time you buy a shoe, add an insert into a shoe or get fitted for orthotics. There are many things you are impacting if the recipe or prescription is not perfect.
Yup, we are the Gait Guys (two aging bald guys promoting gait literacy) and yes, we have the references to back us up. No fluff, just the facts…..
Gait Problem: The solitary externally rotated foot, or “why is my one foot turned out ?”
In a previous post (and on the Cross Over video and hip biomechanics video) we talked about the externally rotated limb/foot as a compensation for a same sided weak gluteus medius. You should recall that in the scenario of a weak gluteus medius, a wonderful frontal plane stabilizer, the foot can turn out to help better engage and protect that frontal plane cheat or compensation by drawing the quadriceps availability into play in that frontal plane. By turning out the foot the knee hinge range goes with the foot and so the quadriceps can now actually help to engage and protect motion into this frontal plane. We call the foot turn out in this scenario, “the kickstand effect”, like a kickstand on your bike, it flips out to add stability in another plane. This is a nice compensation, one seen often, but it has its own set of sequelae such as patellar tracking syndrome, IT band syndrome, trochanteric bursitis and foot pronation challenges to name just a few.
However, there are other reasons for the externally rotated solitary foot. Lets look at another cause.
* Limited internal hip rotation range will be the topic today.
In order to pass through the midstance phase of gait, in walking or running, the hip must internally rotate at least 4-6 degrees. Actually, to be perfectly accurate, since the hip is the fixed part (foot is fixed on the ground) the acetabulum socket of the pelvis which sits upon the hip’s femoral head, must be able to externally rotate those 4-6 degrees on the femoral head in order to get the subsequent full, timely and optimal hip extension and gluteus maximus contraction. So, what we are saying is that the pelvis which is sitting upon the hip’s femoral head must be able to oscillate to accommodate the swing phase of the opposite leg. For example, if the right foot is on the ground the pelvis is going to rotate clockwise upon that right femoral head which has been brought on by the left leg forward swing phase of gait.
Now, if that right hip joint does not have adequate internal rotation, the clockwise spin of the pelvis on the femur head will hit an early limitation end range. We will talk about the consequences in a moment but first we need to remind you of things we have talked about in previous blog posts: when we limit internal hip rotation the degree of hip extension will also be limited. You need sufficient internal rotation at the hip to get the subsequent hip extension and resultant gluteus maximus optimization.
Now, back to the possibilities when the pelvis cannot rotate clockwise enough on the right femoral head (ie. internal hip rotation). A few things can happen as the limitation is reached:
- the left foot (swing limb) can drop to the ground prematurely rendering a short step length
- the pelvis rotation on the hip will hit capsular close packing and compression and come to a halt but the forward momentum of the body-pelvis swing will cause an external rotation pivot of the foot and this extra spin from the foot will achieve the last needed pelvic motion (we call this “cigarette foot”, like putting out a cigarette under the ball of your shoe). Interesting note for those of you who run on crushed gravel or other forgiving surfaces, pay attention to this subtle spin on these surfaces, this could be the spin that you feel at toe off. This is sort of like the Abductory twist of the foot phenomenon, however that is a typically reserved term more for an excessively pronated foot.
- the individual will simply limit their stride length to avoid the above problem range however they will also be limiting hip extension, weakening the gluteus maximus. Premature heel rise will go with this issue (seen beautifully in this video above).
- Since internal rotation is a precursory range before hip extension, if you limit internal rotation you will limit hip extension. When hip extension is limited quite often you will ask for more saggital extension from the joint complex above or below the hip, so looking above the hip we can see increased lumbar extension or below we can see knee hyperextension, both compensation can make up for the loss of hip extension.
- As the internal limitation is met, pelvic obliquity can be adopted to normalize linear saggital gait progression. Eventually the core will become asymmetrical and create a pelvic obliquity distortion pattern which can be seen on static standing, typically a clockwise pattern (if we are talking about the right hip limitation) to enable more of the internal rotation at the hip (re-read #1 to understand this).
- And finally, the easiest of the patterns, the brain sometimes will sense this aberrant pattern and simply turn the right leg-foot outwards into external rotation. Why ? Because, when you move through midstance and hit the internal hip rotation limitation a compensation must be met as described above. If from the start of the gait cycle you merely set the foot progression angle into external rotation (as in the video above), the pattern (albeit dysfunctional) gets to groove the aberrant pattern more smoothly. At the severe cost of weakening the internal limb rotator muscles and gluteus maximus (sacral and coccygeal divisions to be specific) and perhaps even more detrimental losing the advantages of proper toe off of a rigid foot (again, look at the arch collapse, toe hammering and premature heel rise in the video above, there is a price to pay for compensating). In this scenario, you are literally creating the hip range of motion (by externally rotating the limb) that you didn’t have.
Of course the best solution is just to figure out why the internal hip rotation is limited (address both tightness in soft tissues and the weaknesses that drove that protective tightness, yes stretching rarely solves the world’s problems). Then regain symmetry, and the optimal and efficient motor patterns.
And of course, there are neurological sequelae occur as a result of this strategy, but that is the subject of another post on another day.
The externally rotated foot is an adaptive strategy. It is biomechanically brilliant, but fraught with compensations and prostitution of far reaching motor patterns (yes, this pattern will often effect normal arm swing in the contralateral limb, see our arm swing blog posts from last week). Simply telling someone to turn the foot back to forward facing neutral (5-15degrees progression angle) is not the solution. Gosh, if it was that easy doctors like us would also have long tails and be seen swinging from trees eating bananas.
The externally rotated foot. There is more to it than meets the eye. Dig deeper and you will find the answer, if you do not mind some heavy thinking.
Shawn & Ivo, The Gait Guys ……. Rubix’s cube kind of guys.
How long does it take for training improvements to occur ? In today’s neuromechanics weekly video, Dr Waerlop talks about how long it takes for training effects to show effect, and how much of the early strength gains are due to neurological efficiency, rather than muscular hypertrophy. This is why we can all make such dramatic changes in gait in such short periods of time!
Power Leaks: Asafa Powell
We all know Asafa: the Jamacian sprinter who specializes in the 100 meter. World record holder in ‘05 and '08 with times under 10 seconds. Lets take a closer look at some French slow motion footage we found. Remember, these are not criticisms; they are observations. What we see may also not be what is wrong, rather a compensation strategy. We are just looking for some potential power leaks.
We begin at :16
Nice supinated Right hand posture and pronated Left hand, neither of which cross the mid-line of the body, which is an important fact.
(This goes back to our blog posts from last week on arm and leg swing and how they are tandem paired, and when this normal pairing is lost there is likely a problem in one of the limbs. It is a pretty consistent finding, the difficulty is having the detailed muscle assessment skills to accurately find the problem).
The fingers are extended as well (the more extensors the better; remember the function of the cerebellum?) But what about the Left shoulder drop at :19? Remember he is bearing weight on his left leg at this point (at footstance). Did you catch the slight body lean to the right? What could be causing this left shoulder drop ? A possible Forefoot deformity? Short leg? Weak left gluteus medius ? We see this again at :22, but this time on the right side. Could there be something in his foot strike ? We will never know because we cannot examine him.
Look at his nice shoulder extension in the 0:16+ opening seconds. First you have to have sufficient length in the biceps and chest wall musculature to get this kind of extension, and his is awesome. Secondly, you have to have sufficient thoracic spine extension to achieve this, once again Asafa’s is likely pristine. But our point in bringing this up was that generous shoulder extension brought on by posterior deltoids, scapular retractors, latissimus dorsi and triceps and a few others is critical in order to get to optimal hip extension and full gluteus maximus contraction. Limitations in the upper limb will play into limitations in the lower limbs. To hit our point home, look at 1:16, look at the freakishly generous right shoulder extension, from what we talked about here do you think the load into the left gluteus maximus has any power leak ? Not likely ! Amazing !
Now look at his right foot position in the blocks at :59, it is abducted and everted (meaning the foot is pronated and non-rigid); it is even more pronounced from 1:00-1:04. We see extreme valgus at the rear foot, that is a lot of load on the achilles mechanism. This is not what you want to see exploding out of the blocks, even if he is loading posteriorly into that foot to explode off of it. It would be more efficient if it remained supinated or neutral and force the posterior load into flexing at the ankle, knee and hips via plyometric type preload.
At 1:08 notice 2 things; the subtle left lateral bend of the torso and prominence of the left lumbar erectors. Nice linear sagittal load !
At 1:13 he laterally bends to the left as he explodes off his left foot. Could his extensors be overpowering the Gluteus medius? Or is he just keeping his body mass over the power foot ? Did you catch that right knee adducting as it came off the blocks? If you have watched enough sprinters you will recognize this as a likely product of the extreme lateral side-to-side foot positioning of sprinters in the early 10-20 meters to help drive harder and gain speed. It is the same motor pattern used in skaters, it can be a product of increased use of external hip rotation to get to more gluteus maximus and spinal extensors, to gain more power.
Look at the torso flexion at 1:25 and how far forward his head is flexed. It is going to be tough to fire those spinal extensors that way but he is likely just leaning to drive that forward momentum, kind of playing the game of “lets make my legs catch up with the risk of falling over forward”. This seems to prove true at 1:25, 1:29, 1:33 and 1:37. But our point here is that flexion inhibits extension and that is where the power is, so a happy medium must be met to reduce wasted time and power. Additionally, did you see that his thigh doesn’t really extend past zero (hint: look at the torso and angle the thigh makes; you can see this at 1:41 and 1:46. Nice forefoot landing here as well. No lateral to medial load, no cross-over gait in Asafa.
He seems to hit his stride at 2:36. At this point there is a nice, circular gait pattern and he extends his neck more at 2:50, which just keeps getting better.
At 1:17 if you had a keen eye, you will notice something that we have been watching in Asafa for years, there is a kind of skip after exploding off of that left foot in the blocks. Most runners will put the right foot down first but not Asafa, he literally explodes out of the blocks and drags the left toe while he begins to load the right gluteus. We have been thinking about this for a long time. Coach Chris Korfist (whom we work with alot on our elite sprinters) and The Gait Guys have studied this strange left foot phenomenon for a many hours watching Asafa’s starts. We believe it may be serving to to stop any drop of the left side of the body, kind of posting up that left side while the right glute takes its turn to power up.
Finally, lets go back to arms swing observations once more. Compare his “casting open” of the elbow angle. Meaning, the angle at the elbows is never held at a fixed angle such as 90 degrees, the angle is always increased as he enters into the posterior arm swing phase. Sprinters use the weight of the forearm as a weighted pendulum to maximize the triceps and posterior arm drive, which in turn gives more contralateral glute contraction (try it at home, get out of your chair right now and cast the arm swing backwards with more force through the triceps, you will feel the power in the glute push off on the opposite side). In distance runners, this high octane maneuver is a bolus of power that is not in the MO of the athlete. Energy conservation is however, so the elbow is held tight in its angle and the pendulum swings far less.
Potential power leaks? You decide. He is an incredibly gifted athlete either way. Just helping you to increase your powers of observation. Remember, we did not give any strong suggestions as to what is possibly wrong here, mainly because without examination it is all speculation. What is seen on video is rarely ever what is wrong, you are seeing the compensations they are using to get around what is not working correctly. If we could see what was wrong on video this would be an easier game and no one would ever need folks like us to fix things, they would all be fixed by changing what is seen on the video gait analysis. We will go into this theory once again this week when we look at another dimension of the “turned out foot” in someones gait. It is too bad it wasn’t as simple as, “hey dude, your right foot is turning out. Stop doing that !”
We remain…The Gait Guys
Analyzing gait, looking for clues and ways to make people move better ….
Power of Splay: New and improved
This time with some anatomy pix.
Think about triangles. Hey Pythaogoras did! They are powerful distributors of force. Here we will talk about 3 of them.
There are 4 layers of muscles in the foot. The 1st triangle occurs in the 1st layer. Think of the abductor hallucis and the abductor digiti minimi. Proximally they both attach to the calcaneus and distally to the 1st and 5th proximal phalanges. Now think about the transverse metatarsal ligament that runs between the disal metatarsal heads. Wow, a triangle! this one is superficial.
Now think about the adductor hallicus. It has a transverse and oblique head. think about that transverse metatarsal ligament again. Wow, another triangle!
What about the flexor hallicus brevis and flexor digiti minimi? The former originates from the cuboid, lateral cunieform andd portion of the tib posterior tendon; the latter from the proximal 5th metatarsal. They both go forward and insert into the respective proximal phalynx (with the sesamoids intervening in the case of the FHB). and what connects these? The deep transverse metatarsal ligament of course! And this triangle surrounds the adductor triangle, with both occurring the 3rd layer of the 4 layers of foot muscles.
Triangles… and you thought geometry was boring!
Remaining triangular when we need to (because of our pointy heads)…Ivo and Shawn
Keep Digging
We are often asked “What is wrong with this gait?” or “Why do I have pain?”. Sometimes, we are able to provide an explanation which seems too simple, but is often correct. It often corrects the immediate problem, only to have another crop up a few weeks later.
Why?
To paraphrase from the words of SHREK; peoples compensations are like onions; they have layers. Uncovering and remedying one problem often leads us to the next weakest link in the chain.
We still have fond memories of Dr Ted Carrick grilling us in the post graduate neurology program “What is the longitudinal level of the lesion? Most pathologies occur at one locus; if you diagnose more than one, it is usually due to metastasis, multiple vascular occlusions, or clinical incompetence. Is the lesion at the receptor, the effector, the peripheral nerve, the spinal cord, the brainstem, the thalamus, the cerebellum or cerebrum”.
The information to glean here is that often we need to establish and limit our focus to ONE area where the problem could be. This necessitates us thinking through the problem and coming up with ONE problem which could cause all the problems you are seeing. This applies to gait and motion assessment as well.
Think of the patient with r sided knee pain caused by patellar tracking issues. Is the retro patellar inflammation the cause? Not usually (unless there has been direct trauma), it is often the symptom (or compensation). Maybe the cause is a forefoot varus deformity because they cannot descend the 1st ray adequately. Maybe this is due to insufficient extensor hallicus brevis function, or is it the peroneus longus? Maybe it is due to a congenital deformity of the foot. Maybe it is due to a functional (or anatomical)leg length discrepancy. Or maybe it is a problem with the left shoulder…you get the idea.
Keep looking and digging until you have found the 1 THING that can explain what is going on. Maybe it’s the individual; maybe it’s their footwear. maybe something else. If you can’t explain it by a single problem or fault, maybe it is time to run some blood work, send them for a vascular flow analysis, or more often than not; expand our knowledge base.
We are the Gait Guys. Two guys digging deeper and looking for the cause.
Gait Guys/IRRA Running Event Recap
Well, it was a fast a furious 2 days for us. We arrived Tuesday evening and put the finishing touches on the presentation for Wednesday morning. We were up and lecturing, 8AM Texas time and were very well received with many interesting questions. This was one one smart group of retailers!
We then had a photo session and whisked off to the Austin School of Film (Thank You Anna, KIrk and Brian!) to finish filming the rest of the Shoe Fit Certification Program (Excerpts to be posted soon!). A few hours later we were back at the event and met up with Dr Mark Cucuzella (a good friend and colleague of ours; you have seen his videos here on the blog) and David Jonson from Sole Running. We were then off to a mixer and out to dinner with Dick Beardsley (yes, THE Dick Beardsley from the 1982 Boston Marathon with Salazar), his wife, Curt Munson and Daren DeCavitte from Playmakers, and Dr Mark. Thursday morning was filled with meetings, including a Magazine interview with Max Lockwood of the Georgetown Running Company. Then we were off to the airport by 2PM and away we went. We have full days at the clinic today and are looking forward to some much needed rest (and a lot of film editing!) this weekend!
Thanks again for all your support.
Ivo and Shawn
The Krebs cycle rap→
/It is Friday Follies !
here is one for all of you who were tortured in high school and college with the Krebs cycle. Yup, nothing clearly dealing with gait, perhaps gait energy production however.
It geek stuff and so we appreciate it. !
“Arm Swing Part 2. “When Phase is Lost”.
* Important: (this is a continuation of yesterday’s post, December 7th. You must read Part 1 from yesterday to have any chance to make sense to today’s post.)
So, we are back to looking at limb swing again. It is important for you to realize, as put forth in
Huang et al in the Eur Spine Journal, 2011 Mar 20(3) “Gait Adaptations in low back pain patients with lumbar disc herniation: trunk coordination and arm swing.”
that as spine pain presents, the shoulder and pelvic girdle anti-phase (as in drawing above) begins to move into a more “in-phase” favor. Meaning that, the differential between the upper torso twist and pelvic twist is reduced (in the drawing above the lines will laterally converge). IF this anti-phase is reduced then arm swing should be reduced (half truth, this is a topic for anther time). The central processing mechanisms do this to reduce spinal twisting, because reduced twist means reduced spinal motor unit compression and this hopefully leads to less pain. This also means reduced thoracic mobility unfortunately (think about this the next time a shoulder assessment test directs you to the thoracic spine and rib cage mobility). The consequence to this reduced spinal rotation is reduced limb swing. Think about this next time you see someone, a runner patient or athlete, with reduced arm swing especially on one side. Furthermore, according to
Collins et al Proc Biol Sci, 2009, Oct 22
“Dynamic arm swinging in human walking.”
normal arm swinging requires minimal shoulder torque, while volitionally holding the arms motionless requires 12 % more metabolic energy, proving that there are both active and passive components to arm swing. Collins also discovered that among measures of gait mechanics, vertical ground reactive moments are most affected by arm swinging and increased by 63% without it. Wow, 63% !
So, it is all about efficiency and protection. Efficiency comes with fluid unrestricted movements and energy conservation but protection has the cost of wasting energy and reduced mobility through a limb(s) and spine.
Now, digest all of this and we will talk about primitive and modern day man next time…….. think about it…. carrying spears and briefcases, or runners carrying a water bottle for that matter. There is more to this arm swing thing than we are letting on here, but you have to digest this first. Please, take the time to re-read this and yesterday’s post and really “get it” because this is going to likely get a bit complicated. But if you take the time to digest this you will never look at an athlete or patient the same again. Your patient assessments will grow deeper and have more clarity.
There is a reason that in our practices we often assess and treat contralateral upper and lower limbs. If you are paying attention, these in combination with the unilateral loss of spinal rotation or lateral flexion are the things that need attention. And for those out there that do not think that the foot is important (we can think of at least one industry guru who thinks it is a “non-factor”), think about this: When there is insufficient hip rotation unilaterally you can regain some of the loss through increased foot pronation unilaterally. The problem with this is that you compromise the swing phase on the contralateral side when you do that and quire often create an abductory foot twist on the hyperpronated side (due to firing of the medial head of the gastroc to invert the foot and assist in supination). However, if you are trying to walk in a straight line from A to B, you also have yet another option, a subconscious option of putting a axial spin through the whole body, some call this pelvic distortion patterning or pelvic obliquity.
OK, that should keep your heads swimming for awhile until the next post on arm swing. It is not as simple as telling your athlete to swing one arm more, or to stop pulling it across their body; they need to do those things, it is called a “compensation”. Merely addressing that locally is such a crime. If you are seeing an arm swing change, you would be foolish not to look at the opposite lower limb and foot at the very least, and of course assess spinal rotation, thoracic extension and lateral bend, …..all spinal functions for that matter. For your neuro nerds, remember the receptors from the central spine and core fire into the midline vermis of the cerebellum (one of the oldest parts of our brain, called the paleo cerebellum); and these pathways, along with other cerebellar efferents, fire our axial extensor muscles that keep us upright in the gravitational plane and provide balance or homeostasis which the ancient Chinese called Yin and Yang.
Simple log-rolling type patterns on the floor or the spine assessment pattern of your preference will likely show a difficulty or asymmetry unilaterally. Think of the neurological implications of long term unilateral asymmetry, altering neuronal plasticity, and altering our movement patterns (and thus our compensations). Make sure to couple this with specific muscle testing to be as clear as you can. Too many folks rely solely on movement assessments but that can catch you in a lie quite often because you could be seeing a compensation.
Yup, we are The Gait Guys….. we have been paying attention to this stuff long before the functional movement assessment programs became popular. If you just know gait well enough, one of the single most primitive patterns other than crawling and breathing and the like, you will understand why you see altered squats, hip hinges, shoulder ROM screens etc. You must have a deep rooted fundamental knowledge of the gait central processing and gait parameters. If you do not, every other screen that you put your athlete or patient through might have limited or false leading meaning.
Shawn and Ivo … combining almost 40 years of orthopedics, neurology, biomechanics and gait studies to get to the bottom of things.
The Perfect Running Shoe.
/On November 17th we provided this description for Kara Thom in an article she wrote. If you want to see her complete article, head to our archives and find that post for November 17th or click here. for her full article.
Here was our small contribution to her nice piece.
The perfect shoe is one that blends seamlessly with your unique biomechanics without creating a conflict between the foot and shoe. It should complement your strengths yet be as comfortable as a bedroom slipper. The shoe should not attempt to alter the natural playing field, meaning, that the heel and forefoot shoe be relatively on the same plane. The closer the forefoot and heel are to the same plane of function, the fewer the compensations from your foot’s natural biomechanics. The perfect shoe should have some cushion, but not too much. Studies show excessive EVA foam in a shoe can increase impact forces due to biomechanical changes. The perfect shoe should not attempt to control the foot, for that will weaken the foot’s intrinsic strength. Thus, part of finding “the perfect shoe” entails realizing your foot’s deficits and limitations. Shoe fit is a science and an art. Because no two feet are the same, there is no perfect shoe for all foot types. There are multiple foot types all based off of 4 primary parameters: rear foot varus, rear foot valgus, forefoot varus and forefoot valgus. Throw in some anomalies, old injuries, variations in length and height of the arches, some variations in joint flexibility and functional control as well as some weaknesses and you can see why the algorithm for the perfect shoe spreads pretty wide pretty fast.
Shawn and Ivo, The Gait Guys.
Arm swing in gait and running: Part 1.
There is so much more to it than you could ever have believed !
Here are some of the facts in NORMAL gait:
- ipsilateral arm and leg swing are in anti-phase (out of phase) meaning that in the picture above the left leg is in flexion and external rotation while the left arm is in internal rotation and extension. (You cannot tell that the left leg is in external rotation but we know that normal gait parameters dictate a lateral heel strike and external rotation.)
- contralaterally the left leg and right arm are in-phase.
- the shoulder girdle and pelvic girdle are in anti-phase as well. See the arrows overlaying the drawing. This means that, as in the picture above, as the left pelvic girdle (left hemi-pelvis) is anterior (since it moves anterior with the same side leg flexion) the left shoulder girdle is posterior. These anti-phasic motions should be equal and symmetrical bilaterally, if gait is normal.
- * so if you are paying very close attention you will note that:
- the left leg is in flexion and external rotation just like the right arm (flexion and external rotation/supination).
- thus, the right leg is in hip extension and internal rotation just like the left arm.
- This drives the oblique posterior muscular sling from right gluteus to left latissimus/lower-middle trapezius via the multi compartmentalized thoracolumbar fascia. Long ago this was coined the Back Force Transmission System. It was discussed in detail in the Second Interdisciplinary World Congress on Low Back Pain, 1995 (link) which all gait geeks have likely read a few times.
Now, many of you who are in the fields of manual and movement therapies are going to say, “guys, tell us something new and fresh, please ! This is old info going all the way back to Serge Gracovetsky’s "Spinal Engine” 1989 book.“
Yes, we know this stuff is old hat. Gracovetsky’s book was a great read, we just wish it had been longer in pages. But, did you know what these works were asking you to extrapolate from them ?
Perhaps they were reminding us of things like: Internal hip rotation is a precursor to hip extension. In other words, the hip must pass through the internal rotation phase before it starts into hip extension. This means that the opposite shoulder must do the same thing. Go ahead, get up and walk and you will note it yourself. But what you must realize is that if shoulder internal rotation range is lost or limited then the posterior sling will be insufficient and hip extension cannot be achieved as effectively. It works both ways gang ! Remember, it is not only a mechanical phenomenon, it is a centrally mediated neurological phenomenon as well. So, if you are thinking outside of the box you might realize that a frozen shoulder (adhesive capulitis) perhaps cannot be treated effectively or completely if contralateral hip extension or internal rotation are limited. They feed forward and feed backwards between each other as well; functional hip pathology can drive shoulder functional pathology. And so if you try to treat a frozen shoulder without paying attention to the gait neurologic central processing patterns then you can sometimes get the slow progress that is seen by many. Think about this the next time you look at a functional shoulder assessment pattern ! We look at the contralateral hip and gait patterns first and correlate ! Treat the person, not the symptom. And gait is part of how they move and integrate the parts.
Tomorrow we well talk more about arm swing, in "Arm Swing Part 2. "When Phase is Lost”.
Shawn and Ivo … combining almost 40 years of orthopedics, neurology, biomechanics and gait experience to get to the bottom of things … and put it into a digestible form for you. (and sharing some of this in Austin Texas today as speakers at The Running Event…. the nations largest running event.)
"Using Kinect for Xbox 360 and Computer Vision to Analyze Human Gait,"→
/Really !? Now we (and you) have an excuse to get an XBOX 360 and Kinect !
According to Young-Hui Chang, associate professor of applied physiology at the Georgia Institute of Technology, “In the rapidly developing field of gait analysis in prosthetics and orthotics, their project opens avenues to bring personalized rehabilitation to the home. This could potentially reduce medical costs, allowing clinicians to monitor a patient’s progress from a remote site.”
see the link above !
The Gait Guys: Toe Box Sizing Talk, and case study.
Here Dr. Shawn Allen of The Gait Guys talks about some of the basic components of the shoe toe box. He discusses some of the problems in the Western world with improper shoe fabrication and toe box fit and shape. Then he shows a case of a hallux valgus where the distal toe length is shifted laterally into abduction (generally speaking) and with the combination of a widening of the forefoot the subsequent foot length is reduced. Comparing this to the opposite foot shoes that quite often with unilateral pathology foot wear sizing needs some deeper thought, awareness and wisdom. Look for The Gait Guys advanced Shoe Fit DVD program on their website starting in 2012.
Intelligent design.
/“I have a bone to pick with God. If He designed the human body, why did he route the male urethra directly through the middle of the prostate gland, thus causing incredible problems for men as they advance in years.” Anon
“Unintelligent or incompetent design.” That is how Cornell evolutionary biologist Paul Sherman refers to the architecture of the human body. If an “intelligent designer” engineered the human body, he points out, air and food would not travel through the same pipes, making us vulnerable to choking.
After teaching seminars on Darwinian medicine (Neurobiology and Behavior 420 this semester) for more than a decade, Sherman, professor of neurobiology and behavior and a Weiss Presidential Fellow, has developed such insights into the workings of the human body and why things are the way they are. They are quite counter, he says, to the idea of intelligent design – the controversial idea that some things in nature are too complex to be explained by natural selection and, therefore, must be the work of a deity – an intelligent designer.
“As soon as you begin to look at our bodies from an evolutionary perspective you see more and more we are not intelligently designed,” said Sherman. For example, he pointed out that no engineer would design our throats with a windpipe that crosses the tube where food passes. “If you were going to design this to eliminate choking you’d probably put your mouth in your forehead or your nasal opening in your throat. It [the human body] is as one would expect from random mutations of previously existing structures and selection over eons.”
This new approach questions which symptoms the body has acquired because they are useful adaptations and which truly are pathologies………… The Darwinian medicine approach “takes every symptom and asks whether it is pathological or the body’s adaptive response,” said Sherman. The approach questions, for example, if a common cough is serving to rid the body of infection or if it is instead a mechanism by which the disease spreads itself.
Our bodies break down a lot. If we were designed more intelligently, presumably we wouldn’t have osteoporosis or broken hips when we get old. Some evolutionists suppose that the process through which people evolved from four-legged creatures to two, has had negative orthopedic consequences.
We are flawed cardiovascularly. Horses carry much more oxygen in their blood, and have a storage system for red blood cells in their spleens, a natural system of blood doping. Humans don’t. Also, while a lot of aerobics can make our hearts bigger, our lungs are unique. They don’t adapt to training. They’re fixed. We’re stuck with them, and can only envy the antelopes.
All of our pelvises slope forward for convenient knuckle-dragging, like all the other great apes. And the only reason you stand erect is because of this incredible sharp bend at the base of your spine, which is either evolution’s way of modifying something or else it’s just a design that would flunk a first-year engineering student.
Look at the teeth in your mouth. Basically, most of us have too many teeth for the size of our mouth. Well, is this evolution flattening a mammalian muzzle and jamming it into a face or is it a design that couldn’t count accurately above 20?
Look at the bones in your face. They’re the same as the other mammals’ but they’re just squashed and contorted by jamming the jaw into a face with your brain expanding over it, so the potential drainage system in there is so convoluted that no plumber would admit to having done it!
Well, for one thing I would put fewer teeth in our mouths. I would put fewer bones in our face, so that it could drain properly. I would straighten up the pelvis so we wouldn’t have to have that bend. I would certainly take out the appendix so we don’t have that problem and the tonsils, too.
And I did have one other. Some guy from Texas listed a number of things with this and he said, “Actually I would write more, but I have to go pee in Morse code, because some idiot designed my aging prostate." …..talk about the wonderful design of the eye—which somehow has all your receptor cells behind a membrane curtain!
I mean, evolutionarily all of these things make sense but in terms of a reasonable, intelligent design? They’re idiocy.”
This is not the work of The Gait Guys……we cannot even find the source where we obtained this…… it is something we found floating in our archives. “Thinking outside the box” kinda stuff…… stuff we really appreciate. We will be looking for the original work so we can give credit and read more of their stuff. Go ahead and see if you can find more stuff on their work. It reminds us of a few books we read a few years or so ago…… “The Scars of Evolution” by Elaine Morgan and “The Naked Ape” by Desmond Morris. They bring to mind similar thoughts as to how, why, and if man had the right to move from quadripedal to bipedal. (if you believe in evolution that is … and if you do not, then you are either a fan of God creation events … and if you believe in that theory then we will ask you to consider watching our favorite History Channel show “Ancient Aliens”. That will surely shake up things a little for ya ! Just having fun with ya’ll. As we respectfully say, ‘To Each His Own.’.
Shawn and Ivo
Speaking of Lactate…. Here’s the bottom line from Professor Brooks: “The world’s best athletes stay competitive by interval training. The intense exercise generates big lactate loads, and the body adapts by building up mitochondria to clear lactic acid quickly. If you use it up (as an energy source), it doesn’t accumulate.” The job of the athlete is to train in a way that causes the mitochondria to process lactic acid faster and more efficiently. Lactic acid is a fuel. To improve your capacity to use it as a fuel, you must increase the lactic acid load very high during training. (For more details, see my earlier article:http://www.cbass.com/Lacticacid.htm ) Dr. McGuff is on top of this new thinking. He says that high-intensity intervals and high-intensity strength training both perform the same function: they improve aerobic function by forcing the mitochondria to burn lactic acid more efficiently. “It is during ‘recovery’ from high intensity exercise that you’re actually getting an increased stimulation of the aerobic system equal to or greater than what you would get from conventional steady-state ‘aerobic’ exercise,” McGuff writes. “If you have been subjected to proper physical training, you can actually make good use of the lactic acid that is produced. If you are intent on improving your aerobic capacity, it’s important to understand that your aerobic system performs at its highest level when recovering from lactic acidosis,” McGuff adds. “It is also important to understand that since muscle is the basic mechanical system being served by the aerobic system, as muscle strength improves, the necessary support systems (which include the aerobic system) must follow suit.” To improve the ability of your aerobic system to use lactic acid as a fuel, McGuff says: Lift weights. And then, let your mitochondria take over from there. Get your aerobic benefit on the “drive home from the gym or off to lunch or back to work.” For McGuff, productive exercise begins and ends with strength training. THE key stimulus for strength—and aerobic fitness—is high-intensity muscular effort. To see and hear Dr. McGuff explain, in 5:50 minutes, just about everything we’ve talked about so far—and why he believes ‘cardio’ really doesn’t exist—visit You Tube: http://www.youtube.com/watch?v=RiHhc7eLpQY
Evidently, we are not the only people who find feet sexy.
http://ngm.nationalgeographic.com/ngm/0609/feature2/online_extra05.html
Here is an interesting National Geo Article contrasting and comparing the shoe and the foot: which is sexier? You decide for yourself.
Two guys, usually liking feet more than shoes….The Gait guys
