A young lady with knee recurvatum. Even at the airport you are not safe from The Gait Guys !

Standing waiting for my parents luggage I had to do a double take when i saw this excessive genu recurvatum of the knees. Of course it was much worse in person because of the added dimension that a photo cannot give.  This poor gal probably doesn’t even know she needs us. 

What do we see here and what assumptions can we extrapolate (assumptions from mere standing of course)  ?:

We are going to keep it to things from pelvis down or we will be here all day.

1. Anterior pelvis tilt. She appears to be sitting back into her pelvis so to speak, doing so we can see an increased lumbar lordosis pressing the pelvis anterior.  Combine this with suspect weak lower abdominals and the pelvis drops in the front. This position is often met with isometric contraction of the gluteals helping to maintain the forward/anterior shifted pelvis.
2. The above, will create an abnormal (possibly increased) tensile load on the hamstrings since the ischeal tuberosities are being drawn cephalad (up). This can create a net posterior shift of the knee joint since she is in relative hip extennsion.
3. The knees are likely locked into hyperextension. This will create meniscal tensions and certainly cause increased patellofemoral pressures.  This can also create the rarely diagnosed, but often present, anteriormeniscofemoral impingement syndrome. In this type of presentation the anterior compressive forces are so great compared to what should be balanced forces around the entire joint that the superior leading edge of the anterior mensicus (can affect medial or lateral menisci) begins to become impinged and irritated as the femur rolls and translates too far anterior. You have to know it exists to make the diagnosis.
4. She will be in relative ankle plantarflexion instead of balancing the tibia neutrally over the talus.  Relative constant plantarflexion means shorter posterior compartment (gastroc-soleus) and usually weak anterior compartment (tibialis anterior and long extensors of toes).  If she is a runner we bet shin splints were on her holiday list of things to resolve. This gal will likely have problems controlling pronation we suspect because of such assumed imbalances.

These are just the sagittal plane flaws we can assume. There are more but this is plenty to think about right now. I was going to walk behind to take a pic so we could make some assumptions about the frontal plane, but people all around were already getting suspicious of me snap photos of so many of them. 

Remember, these are just assumptions from a single static photo. Like in video analysis, anything you pic up on film is just a compensation. It does not tell you what you have wrong until you can test them for neuromuscular integrity and motor pattern assessments.  Do not hang your hat on photos or video analysis. Do the extra work that is required.  After all, you know where ASSUMPTIONS get us.

Oh, and we must not forget to once again thank Mr. UGG boot for helping add another dimension of challenge to this lovely lady ! Although this assumption would be better made off of a frontal plane photo.

Beware of geeks in the airport and shopping malls snapping photos and video. It is likely us, The Gait Guys.

Shawn and Ivo

At this time of year, we are thankful for people like you and appreciate the trust you put in us.

 

In the words of Helen Keller:

The best and most beautiful things in the world cannot be seen or even touched. They must be felt with the heart.

Wishing you Happiness, Health and Prosperity (and excellent gait mechanics).

 

Ivo and Shawn

A case of plantar foot pain during gait.

This client came to see us after a surgical proceedure to remove a dead (osteonecrosis) medial sesamoid under the 1st metatarsal head and a later surgery to fix a progressing hammer toe of the 2nd digit. What we really want you to see is the huge divot/depression under the 2-3 metatarsal heads. Also note the accumulation and relocation of the normal MET head fat pad now located distal to the MET heads.  It is as if the fat pad is trying to hitch a ride on the toes now ! This is a case of Metatarsalgia secondary to fat pad displacement (displaced from the divot area to the flexor crease) secondary to surgical sequelae. 

What is additionally cool in this case is the fact that this client has an almost complete webbing of the 2-3 toes so many of the normal independent muscular functions are no longer independent. After the surgeries this person presents with tremendous loss of flexor and extensor function of the 2-3 toes.  Lumbrical testing was most obviously impaired, completely absent in fact, in these 2-3 toes. On the ground the patient was also unable to achieve any flexion-press of the toes into the ground, he was able to flexion/hammer curl which will obviously put them at risk for hammer toes in the future.  But what is important here is that without the ability to PRESS the toes into the ground particularly while in stance phase the lumbricals will not help to hold the fat pad in its normal location under the MET heads. Nor will they be able to to perform their other major functions, namely: thinking from a distal to proximal orientation (a closed chain mode of thinking), they actually plantarflex the metatarsal on the fixed phalynx, assist in dorsiflexion of the ankle, and help to keep the toes from clawing from over recruitment of the flexor digitorum longus.

This client’s MET head pain is obviously caused by lack of cushioning of the head since the fat pad is displaced. There are plenty of other biomechanical abberancies now, the Windlass mechanism will never be the same becuase it is without one of the sesamoids, the hallux short flexor (FHB) is impaired on the medial head without the sesamoid so hallux flexion will become a problem.  Do we really want to see such compromise of the medial tripod ? Heck no, we need sesamoid implants ! There is a novel idea ! When a sesamoid is taken out we need to replace it ! Think about it !

There is so much more to this case, but we will stop here. It’s Christmas after all ! This poor lady was told to wish from Santa for a medial sesamoid implant under the tree and a sudden spontaneous activation of the lumbricals to retract the fat pad back under the MET head so as to reduce her pain.  Hey, wishing can’t hurt !

Merry Christmas and Happy Holidays to you all gang, whatever your faith we wish you well,

from Shawn and Ivo…… The Gait Guys

(PS: we included below more from the body of the article we wrote long ago called “The Lost Lumbricals”.  So for those of you who wish to geek out more on Christmas, read on …

______________

EXCERPTS FROM “THE LOST LUMBRICALS”

The lumbricals of the foot attach proximally to the sides of adjacent  tendons of the flexor digitorum longus (with the exception of the 1st, which only attaches to the medial side) and attach distally to the medial aspect of the head of the proximal phalynx and continue on to the extensor hoods in toes 2 through 5. Their typical function is described as flexion of the proximal phalynx and extension of the proximal and distal interphalangeal joints. They have the unique ability to compress the metatarsal-phalangeal and interphalangeal joints. These are “open chain” functions as described, unless you are in the habit of waving to people with your toes, they often are used quite differently in the gait cycle with the foot affixed to the ground.

The lumbricals are most active from midstance to preswing. That means they act predominantly in the closed chain. The lumbricals, along with the other intrinsic muscles of the foot, play a role in maintaining the medial longitudinal arch of the foot.  Along with the interossei, they play a role in stabilization of the forefoot during stance phase and rearfoot during preswing. One author has proposed that overpronation is due to a lack of neuromuscular control of the intrinsic foot muscles to stabilize the tarsal and metatarsal bones and therefore modulate the speed of pronation.

Thinking from a distal to proximal orientation (a closed chain mode of thinking), they actually plantarflex the metatarsal on the fixed phalynx, assist in dorsiflexion of the ankle, and help to keep the toes from clawing from over recruitment of the flexor digitorum longus.

Clawing toes during gait, which are considered abnormal, are defined as extension of the metatarsophalangeal articulation, and flexion of the proximal and distal interphalangeal joints result from a foot attempting to stabilize itself during the terminal stance and preswing phases of gait.  This is an attempt to help propel the body forward, often accompanied by overactivity of the flexor digitorum longus, tibialis posterior, flexor pollicus longus, and gastroc soleus groups. Overactivity of these groups causes reciprocal inhibition of the long toe extensors and ankle dorsiflexors (tibialis anterior for example), causing the toes to buckle further and a loss of ankle dorsiflexion; in short, diminished ankle rocker.

Now think about the changes in the gait cycle in the above scenario. There will be a resultant shortened step length, diminished ankle rocker, increased forefoot rocker and premature heel rise. This will necessitate an increased extension at the metatarsophalangeal joints, shifting the tendon of the lumbricals upward and behind the transverse metatarsal joint axis, causing even more extension now at this joint. Chronically over time, this causes displacement of the fat pads anteriorly from under the metatarsal heads and is one of the main reasons metatarsal head pain (metatarsalgia). In the past have you made the apparent simple diagnoses of metatarsalgia, shin splints, stress fractures or Morton’s neuroma without knowing a more plausible cause ?  Do you now feel you have better answers to these clinical phenomena ?

Now think about changes up the kinetic chain and the potential musculoskeletal implications of muscle inhibition, overfacilitation and joint dysfunction, often with neurological sequelae. With lumbrical dysfunction (weakness) and the resultant lack of ankle dorsiflexion, you have less hip extension.  So, you borrow some from the lumbar spine, with increased compressive forces there and an increase in the lordosis, which causes an increase in the thoracic kyphosis and cervical lordosis. We still need to get this leg up and forward to continue our progression ahead, so now we fire our hip flexors instead of the abdominal obliques. And because there needs to be cooperation of the abdominals and hamstrings to maintain pelvis neutrality, this further fuels inhibition of the gluteals thus further compounding the loss of hip extension. Now how about a little increased shoulder flexion on the contralateral side to assist getting that leg forward? Don’t forget that we have altered the thoracic kyphosis and thus changed scapulo humeral mechanics. Now neck/shoulder pain all from bad feet?  Maybe. These muscles developed and exist for a good reason, do your best not to dismiss them and their function the next time you see a tortured foot.

When patients have continued dysfunction, consider the base and where it all begins. Consider function in the context of where it occurs. Proper evaluation of the feet and gait can provide valuable clues as to the etiology or manifestation of continued problems. Important? You decide.

Are aging runners less economical ?→

As the year comes to an end many will begin to think about their future health. Many will start running. Starting is often the hard part, trying to get the old machine working again can take a little time. And as we age, it is not uncommon to get demoralized by the decline of our abilities and performance. This study in the Journal of Strength & Conditioning Research gives hope to us all as we age and for those that are just starting out. Bottom line, it is just going to take a little work.

The study shown below concluded that the runners over 60 were just as economical as even the youngest ones in the study. Oxygen utilization was just a efficient. The obvious problem is that as we age the other parts are not quite as youthful. Muscular strength, muscle mass, tissue elasticity, cartilage pliability etc all reduce and so power output and other parameters reduce.  The good thing is that with sensible training, all areas can be improved which when combined with a system that is still economical into our aging years, we can all still see some pretty bright days ahead of us.  Sure the parts are going to be more apt to breakdown and tolerate less, but even into the golden years, our discussions about training smarter, not harder still hold true.

We have attached the info for the article if you want to find it for your clientele or for your office or gym.                                                                                                                                       

 

J Strength Cond Res. 2011 Nov;25(11):2971-9.

Aging and factors related to running economy.

Quinn TJ, Manley MJ, Aziz J, Padham JL, MacKenzie AM.

Abstract

The purpose of this study was to investigate the relationship that age has on factors affecting running economy (RE) in competitive distance runners. Fifty-one male and female subelite distance runners (Young [Y]: 18-39 years [n = 18]; Master [M]: 40-59 years [n = 22]; and Older [O]: 60-older [n = 11]) were measured for RE, step rate, lactate threshold (LT), VO2max, muscle strength and endurance, flexibility, power, and body composition. An RE test was conducted at 4 different velocities (161, 188, 215, and 241 m·min(-1)), with subjects running for 5 minutes at each velocity. , , , 

Bottom line from the study: The results from this cross-sectional analysis suggest that age-related declines in running performance are associated with declines in maximal and submaximal cardiorespiratory variables and declines in strength and power, not because of declines in running economy.                                                                             

 

Gretchen Reynolds wrote a great article for the NYTimes last week on this topic.  The link to her article is above. “For Older Runners, Good News and Bad.”

Just a fun foot commercial to brighten your Friday

Have a good one.

Ivo and Shawn

This video pretty much sums up our entire philosophy. Skill, Endurance, Strength; in that order. Why? Skill requires the largest diameter afferent (sensory) nerves to accomplish (Ia and Ib afferents from muscle and joint mechanoreceptors); they are the fastest pathways; Endurance comes from larger sized Type I (and sometimes Type IIa) endurance muscle, which are oxygen dependent (aerobic) and are rich in myoglobin, glycogen, mitochondria and capillaries; Strength last, because it comes from smaller, Type IIb fibers, and is largely glycolytic (depends on anaerobic respiration) and is dependent on the other 2 (skill and endurance).

When you take amazing skill and body awareness and combine it with strength and flexibility and control you can do these kinds of wild things.

Exploring the links between human movement, biomechanics and gait.

The Gait Guys

The documentary investigates Kenyan runners and how against all odds a the small town of ITEN produces the best world class runners seen worldwide. This is a teaser trailer

Gait, Running or Biomechanical problems ? Today we talk of Torsions and Versions….

(excerpted from the forthcoming second edition of our book)

We’ve all heard of, and probably have used, the terms torsion or version especially in the vernacular of antetorsion or anteversion and retrotorsion and retroversion. We (including authors and researchers) often like to use these terms interchangeably. Technically speaking, we have all been wrong.

Believe it or not, there was actually a group of folks in 1979 called the Subcommittee on Torsional Deformity and Pediatric Orthopedic Society whose mission was to set people straight on the differences between torsion and version. Version is actually the normal difference in angulation of the proximal and distal portions of a long bone. Torsion is said to be present when this measurement falls outside 2 standard deviations of the normal version.

Versions are present in utero and are considered part of the developmental process. For example, the femur has approximately 30 degrees of anteversion at birth (ie the femoral condyles are rotated 30 degrees medial to the plane of the femur head). During the normal developmental process, the femur “untwists” at a rate as slow as 1-3 degrees per year to approximately a 20 degree by age 6, leading to a “normal” angle of 8-12 degrees of anteversion. Of course this can occur slower or faster or to a greater or lesser degree as well resulting in a torsion, which may or may not have symptomatic sequela later in life. Regardless, these torsions are very important transverse plane deformities from a gait biomechanists point of view in regards to resultant compensations which occur in the lower kinetic chain and more proximally.

These versions and torsions can affect any long bone, but most important to us, the femur and tibia. Of interesting note, there is a 2:1 preponderance of left sided deformities believed to be due to most babies being carried on their backs on the left side of the mother in utero, causing the left leg to overlie the right in an externally rotated and abducted position.

Now maybe you will think twice about the position of the feet of a newborn when placing them on their stomach, as this posturing will effect their development over time and potentially contribute to adult torsional deformity! How’s the sleeping position of your child? Do they consistently sleep on one side? Is their thigh drawn up and internally rotated with a compensatory external rotation of the foot relative to the tibia? Wow, and you thought as long as you fed them well and didn’t let them watch too much TV that all would be OK!

Torsions and Versions…. They are not just for breakfast anymore…

Yes, we ARE a little twisted……Ivo and Shawn

We are giving up one of our deep secrets today.  We figure you guys are worth it.

There is a reason we have followed Allen Lim from his days of Team Radioshack and even before that with Team Garmin.  His work on temperature regulation in athletes was fascinating and his knowledge in nutrition is pretty solid too. Everything Allen does, we recommend to our athletes.  We keep our high school and college athletes in air conditioned vans and hotel rooms until moments before big meets (while other teams have their athletes sitting in the heat and sun), we recommend super hydration days before long races, super cold water before races to promote gastric dumping and reduced core temperature, and we teach them about the hydration and glycogen time frame windows. Mere fractions of a temperature spike reduce performance.  It is all good science. If you are one of our patients and athlete, you get the talk over and over again. If Allen is doing it, we look at it pretty closely.

Watch this video and find the company name in the interview.

don’t say we don’t give away the farm from time to time !

The Secret double agent Gait geeks ……. always looking for the edge for our peeps.

Shawn and Ivo

Gait, Running and Muscle fiber types & Why you want to train to mimic your sport.

This weeks neuromechanics explores muscle fiber types, the characteristics of each, and what that means for training. How does that relate to gait?

Our lower extremity muscles are a mix of strength and endurance muscles and each must be trained (or retrained) appropriately. If you lack endurance capacity in your gluteus medius (commonly seen with fatigue and manifesting as a pelvic dip), strength training will not help the problem… in fact, it will make it worse! Larger cross sectional area with less mitochondria, fewer capillaries and less myoglobin only fuels more anaerobic glycolysis (read LACTIC ACID PRODUCTION); if you cannot recycle this appropriately, your endurance goes down. Remember, exercise is specific as to the type of contraction (isometric, isotonic, isokinetic) as well as the speed of contraction.

Have your attention? Watch the video!

We Are and will remain The Gait Guys: piecing it together so you don’t have to.

Functional screens will not always give you the answer, the screen might only show you another level of compensation. Only the keen at that game will get it right. What do we mean by this ? Well, lets take muscle testing and motor pattern assessments for example.

When we started with muscle testing we used to look for the weakness of the muscle or pattern we were isolating. But now, with more experience and wisdom, our keen eyes are now focused on the clients attempts to “cheat” around the assessment rather than basing our assessment entirely on the isolated tests. Many athletes will quickly figure out how and where to get more strength in a given muscle test, often because they are used to compensating for a weak muscle…..studies even show that clenching your teeth, or squeezing another muscle (often called a Jendrassik Maneuver) can affect the outcome of a muscle test.  So, you have to watch for your client’s attempts to “cheat” through your assessments.  Just one more thing to think about! 

In the screen above, would you know if the person had internal or external tibial torsion?  How about femoral retro or ante torsion ? In doing a screen, only the astute assessor will know what the screen is telling them.  For example, is the foot turned out because the person has external tibial torsion, or is the knee going inwards because they neutralized the foot progression angle before the test and now the knee is drifting inwards ….. it is still external tibial torsion in both cases.  What about internal tibial torsion, where is the foot, where is the knee? (More on Torsions and Versions in Thursday’s post)

The squat can give you information but you might want to think about this.  Really how useful is a squat in relation to the most fundamental pattern we use the most, gait ? Well, it is not. 62% of normal gait is stance phase and of that, 51% of that is on one foot (38% of a total gait cycle). We still vividly remember when Professor Janda visited our residency program back in the 90’s for a week.   He spoke of many things but one that stuck with us was a discussion about the need for stable single leg stance function, that it was a key motor skill easily cheated.  That is not to say that the squat test is not a valuable assessment, there are just better ones in our humble opinion.

You see, a functional screen does give information, but it is only the person who understands the parameters of normal and abnormal function and anatomy who can glean what the screen is telling you. Guys like Gray Cook  who are big into this stuff are going to be awesome at this because they have the background to know what the test is telling them and know the anatomical parameters that can skew the test.  What we are saying, is that it is not the test that is the gem, it is the knowledge to understand the results of the test that is the key.

Oy vey, why can’t anything be simple,  huh ?!

It’s Tuesday, we are The Gait Guys…….. and so much more.

Shawn and Ivo

The Solitary Turned out Right foot in a Barefoot Runner: Part 2

Here is a perfect example why we sometimes cringe when someone comes into our office with pain or problems and wearing minimalist shoes or worse yet, claims to be a barefoot runner.  This is a perfect example of a client, whether they are in your shoe store or in a medical office, that needs to be convinced to remain in their more stable trainers until the problem is unwound. 

In this video it is plain for anyone to see that the right foot/lower limb is clearly externally rotated and pronating excessively when compared to the left side.  This could be from weakness of the gluteus medius, loss of internal rotation or one of several other biomechanical flaws (be sure to review Dec 15th blog post on these topics ). However, it could also be anatomic.  This could be from external tibial torsion or a torsion at the femur.  Regardless, it is likely creating a functional short leg on the right because when we pronate heavily like this, the height of the talus and arch drops further than normal, and in this case further than the other side.  However, one could argue the opposite, meaning that this person is pronating heavily on the right to shorten that leg to be equal to an already shorter left leg. In order to know, and not guess, you have to assess your client.  As indicated above, the internal limb spinning pronation could be a compensation to gain more entire limb internal rotation from a loss of hip rotation. Yes, there could be many causes. In this latter case, prescribing an orthotic to dampen this pronatory excess would be a mistake for the hip even though it would be a logical intervention at the foot level.  Our direction would be to find the cause of the right limb turn out and hyperpronation.  Video gait analysis and guessing will not get you there.  You have to assess your clients neuromuscular ability and deficits.  If one were to bet on impaired internal hip rotation, a fairly high probability bet, then how many internal rotators of the lower limb can you name immediately without looking them up ? You will need this info at the tips of your fingers in an exam if you are going to prove or disprove the internal hip rotation theory.  Here are a few to get you started:

• vastus lateralis
• TFL-ITB
• anterior head of gluteus medius
• reflected head of rectus femoris
• adductor brevis
• coccygeal division of gluteus maximus
• how many others can you name and accurately test so that you are not guessing when it comes time to assess your client ?

Welcome to the complex game we play every day with our athletes and “every day Joe’s”. It is a brain knocking game, and  you have to juggle many factors while sorting it out. ! Tomorrow we will talk a little about possible problems of Functional Screens and how they can be used to help assess, but also how they can fool you.

Have a good Monday gang….. and watch for the rampant spreading plague of the turned out foot.  It is nationwide already !

Shawn and Ivo, The Gait Guys

Arm Swing Part 3: Running Downhill on Uneven Terrain.

Today we have a pretty cool video for you. It is perfect stuff for a Sunday blog post. It is called “The Chase”. This team has done something pretty neat and this probably took alot of time to complete. Notice it is the same guy in two different outfits (red chasing black), giving the impression of him chasing himself. It is about pushing yourself to be the best you can.  But there are some clips at 2:17 we want you to pay attention to. Watch his arm swing when he is scrambling down the hill. The arm swing is tight, controlled and helps his core and balance. But there are other costs to doing this, and it gives perfect support to our blog posts from a few weeks ago on arm swing.

If you have not read our posts from December 7-8 (link) it might behoove you to read them now otherwise today’s topic will have limited meaning to you. We are building on this topic of limb swing, and how some of it is passive and some is active from a neurologic control standpoint. 

So, we are back to looking at limb swing again. Particularly arm swing today.  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 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). In our opinion, in threatening motor challenges (such as running downhill at 2:17 in the video above) the body will create a reduction in spine rotation and motion due to the increased activation of the core to maintain balance and stability.  IF this anti-phase is reduced then arm swing will be reduced (as is seen when he is scrambling downhill). 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 but also more body control. 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, taking this data, one could extrapolate that energy consumption is increased running downhill on uneven terrain. This may be nullified by moving with gravity and the downhill slope.  But on such uneven terrain, if you are smart and not reckless you will be expending energy to slow the downhill chaos so you can remain in control of the descent.  This goes for flat uneven or slippery terrain as well, keep this in mind when you hit some icy patches this season. Thing of The Gait Guys, and note how your body adapts to the surface. The surface has huge impact on how you use your body.

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.

For you 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. And when running downhill you had better be firing your extensors !

Shawn and Ivo …  combining almost 40 years of orthopedics, neurology, biomechanics and gait studies to get to the bottom of things….. to help you become better athletes, better coaches, and better doctors.

Gait Video Case of the day: The Frontal Plane Hinging Knee.

This is both a simple case, and difficult one. Simple because the diagnosis is easy. Difficult because there is not much you can do for it. But you still have to recognize it.

This person came to see us with a chief complaint of left hip and knee pain and right medial foot pain. It should be simple to see that the left knee is degenerative particularly in the medial compartment of the knee. You can see with the person walking that when the left leg is loaded there is a frontal (sideways) shift of the knee to the outside. This gives the appearance of a bowed (genu varum) knee. What you need to see and understand is that when they load the limb the knee moves laterally to the outside and this is going to challenge the left hip, particularly the gluteus medius, but it it is also going to press the lateral trochanter bony prominence of the hip into the bursae and soft tissue structures like the IT band.  Both of these soft tissue structures can become quite inflamed and painful. Fatigue failure of the left gluteus medius in this kind of case will lead to pelvic obliquity and abdominal asymmetry and difficulties with symmetrical core stabilization of the spine. Low back pain is not uncommon in these types of cases.

So why the RIGHT foot-ankle pain ? Well, when the left knee moves laterally the hip and pelvis move laterally very suddenly rendering a kind of functional short leg on the left but it will also, as you can see in this case, an abrupt lurch onto the right limb. This sudden lurch onto the right is because the brain knows that the left limb is unstable and challenging an improper plane for the knee (it is only supposed to hinge forward and backward) and so the weight bearing phase on the left is abbreviated. And so, when you abbreviate the stance on the left the right side is loaded sooner, longer and faster.  In this person’ case, the loading as such has been going on for so long that the pronation phase has become excessive enough to pound down the right arch and challenge the right tibialis posterior muscle. Remember that  the tib. posterior is designed to invert the rear foot (look carefully in the video, the client has lost this ability and the rearfoot is constantly everted) and it also helps to stabilize the longitudinal arch of the medial foot. In this case, the client has undergone such excessive loads into pronation that she is now hyperpronating. The tibaialis posterior has developed longitudinal intersubstance tears which now need surgery quite possibly. 

This is a left knee that needs replacing asap to not only reduce the left knee issues, but to dampen the challenges into the left hip (so surgery there is avoided) and so that the timely stance phases on each foot can be restored and ease the burden on the right tibialis posterior and arch stabilizers.

Intervention ? perhaps temporarily, reduce the lateral shift and functional drop on the left with a full sole length lift. We start with 2mm of rubber infused cork and see them again in two weeks to see if more is needed. This will reduce all of the gait aberrations noted above, but it does not fix the problem. You are managing the issues for the client, buying them time.  Adding an orthotic on the right foot can be done, to slow the pronation, but if the height of the orthotic is too much they will pronate into it and cause plantar pain from meeting the orthotic with force.

This is a pretty classic degenerative knee gait. We see this one in our offices several times monthly. Look for it ! We get some wild and worn body parts coming into our offices. Everyone walks so everyone gets a gait evaluation and an examination to prove or disprove the deviant gait appearance as part of the present clinical picture.  Once you get good at the stuff and train your eye after many years, like us you might not need a treadmill or slo-mo camera.

Shawn and Ivo, the gait guys.

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 1^st 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 1^st 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:

1. the left foot (swing limb) can drop to the ground prematurely rendering a short step length
2. 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.
3. 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).
4. 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.
5. 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).
6. 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