Do you know how you run?

If the answer is yes, then the second question is ”How would your running technique change if you were bare foot?” 

The reason these questions are important is straightforward.  We think your body was designed to do its job best without shoes.

Stepping backwards in time a little, in the caveman days things were different.  The foot was unshod (without shoes) from the moment of the first step until one’s dying day, and thus the foot developed and looked different.  The sole of the foot was thicker and callused due to the constant contact with rough and offending surfaces thus preventing skin penetration. The foot proper was more muscular and it was often wider in the forefoot and the toes were likely slightly separated due to the demands of gripping, which would necessitate increased muscular strength and bulk to the foot intrinsic muscles. 

It was the constant input of uneven and offending surfaces such as rocks, twigs, mud, foliage and debris that stimulated the bottom of the foot, and thus the intrinsic muscles, sensing joint positions and relaying those variations to the brain for corresponding descending motor changes and adaptations to maintain protection and balance.  The foot simply worked different, it worked better, and it worked more like the engineering marvel that it truly is. 

Most animals on this planet run on their toes or forefoot. This allows for a more active control of the impact that will be placed on the lower leg, which in turn will decrease the rate of  injury. If you have a large heel cushion and you land on your heel you are asking the cushion to take the place of your brain. The last time we checked, air filled foam couldn’t think all that well.  In the last few years  there has been a return to bare foot running. But it is not necessary to go barefoot to gain the benefits. You can just change your running style. 

When running either shod or unshod, to minimize injury, try and remember the following points:

Where does your foot strike the ground? Your point of contact or strike should be somewhere between the mid foot and the ball of the foot.

Where is your center of gravity relative to your point of contact with the ground? Your center of gravity, which is located in about 2 inches below your belly button and in the center of your abdomen, should be directly over or slightly forward of your point of contact.  This is accomplished by leaning forward at the ankle.

Make sure you activate your core muscles, including your abdominals and glutes. Your abdominals should be active when your foot is in the air and your gluteals when your foot is on the ground.

This is how you would run if you were bare foot and it is how you should run in shoes. If you do nothing but apply these to changes to your running you will be well on your way to becoming a more effective runner. 

The Gait Guys give special thanks to Dr John Asthalter, who contributed to this article

Beautiful Glutes: Part 3

Here is the part you have been waiting for…

Functional Perspectives

It would logically follow that the gluteus medius is important for generating both forward progression and support, especially during single-limb stance suggesting that walking dynamics are influenced by non-sagittal muscles, such as the gluteus medius, even though walking is primarily a sagittal-plane task. After midstance, but before contralateral preswing, support is generated primarily by gluteus maximus, vasti, and posterior gluteus medius/minimus; these muscles are responsible for the first peak seen in the vertical ground-reaction force. The majority of support in midstance was provided by gluteus medius/minimus, with gravity assisting significantly as well.

Seemingly, the gluteals appear important for extension of the thigh during gait. One of the most common scenarios appears to be a loss of ankle rocker and resultant weakness of the gluteals (personal observations). Lets look at an example.

Have you ever sat at the airport and watched people walk? We all travel a great deal and often find ourselves passing the time by observing others gait. It provides clues to a plethora of biomechanical faults in the lower kinetic chain, like a loss of ankle rocker with people who wear flip flops or any other open backed shoes.

What is ankle rocker, anyway? According to Jaqueline Perry (THE Matriarch of Gait Analysis) during normal gait, the stance phase (weight bearing) foot depends on 3 functional rockers (pivots or fulcrums) for forward progression.

· heel rocker: at heel strike, the calacaneus acts as the fulcrum as the foot rolls about the heel into plantar flexion of about 10 degrees . The pretibial muscles must contract eccentrically to slowly lower the foot and help, along with forward momentum, pull the tibia forward

· ankle rocker: next, the ankle acts as at fulcrum and the tibia rolls forward due to forward momentum, with a maximum excursion of approximately 15 degrees. The gastroc and soleus should eccentrically contract to decelerate the forward progression of the lower leg.

· forefoot rocker: the metatarso-phalangeal joints act at the final fulcrum in the stance phase of gait. Note that the 1st metatrso-phalangeal joint must dorsiflex 65 degrees for normal forward progression, otherwise the individual will usually roll off he inside of the great toe. Tibial progression continues forward and the gastroc/soleus groups concentrically contract to decelerate the rate of forward limb movement. This, along with passive tension in the posterior compartment muscles, forward momentum , and the windlass effect of the plantar fascia result in heel lift.

Now watch someone walking in flip flops or open back shoes. There is no pivot past 90 degrees at the ankle (i.e. the tibia never goes beyond 90 degrees vertical). At this point the heel comes up (premature heel rise) and the motion must occur at the metatarso-phalalgeal joint. The only problem is that this joint usually has a maximum of 65 degrees extension. Since more is now needed, the body borrows from an adjacent joints, namely the knee (which increases flexion) and the interphalangeal joints (which should be remaining flat and now must claw to “create” more available extension at the middle joint, as the proximal is nearly fully extended, through overactivity of the flexor digitorum longus. The tibialis posterior, flexor hallicus longus, and gastroc soleus groups also contract in an attempt to help stabilize the foot . 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 function.

So there you have it. Glutes. They are a beautiful thing! Isn’t it great to be a gait nerd?

We remain..Gait Nerds and ….The Gait Guys….

Beautiful Glutes: Part 2

We are going to get a little techie here. Hang in there!

EMG data

There are a paucity of studies on gluteal function during gait, but here is what is out there.

The upper and lower portions of the glute max shows activity at initial contact and near the end of swing phase, the middle portion additionally just before and after pre-swing.  The glute max does not appear to be a postural control muscle, nor is it utilized in static one leg standing, except when a large load is imposed  When the center of gravity of the whole body is grossly shifted, the gluteus maximus becomes engaged. The glute max, along with the vasti also assist in deceleration of the body during the first half of stance.

The gluteus medius and minimus appear to play a much more substantial role in propulsion and stabilization during normal gait, contracting from terminal swing to preswing, maximally during early midstance, to prevent contralateral drop of the pelvis. The anterior fibers of both appear important for gait, as they assist the external obliques in forward progression of the pelvis on the side oppposite the stance phase leg, in addition to supplying coronal plane stabilization. A brief burst of activity in midswing assists in medial rotation of the thigh. Gluteus maximus fuction can be affected by  altered biomechanics and the g luteus medius commonly affected by postural faults.

Wow, betcha didn’t know that! Stay tuned for part 3!

We remain…The Gait Guys.

Beautiful Glutes!     Part 1

Place your hands on your buttocks and stand up from a seated position. Did you feel them fire? Now walk with your hands in your back pockets. Do you feel them active at the end of your stride? No? Maybe you should be in rehab. You should!

The glutes have been the fascination of many, including Michaelangelo (Ever seen the sculpture of David?). Perhaps if you have a patient with recalcitrant back or hip problems, you should consider looking closer at their gluteal group.

anatomical perspectives

The gluteus maximus, the most superficial of the 3 gluteii, is the largest, coarsest fibered muscle in the body. It attaches proximally on the ilia, sacrum, coccyx and sacrotuberous ligament and slopes 45 degrees inferolaterally to attach distally, predominantly to the iliotibial tract with a smaller contribution attaching to the gluteal tuberosity of the femur. In open chain, it is an extender and lateral rotator of the thigh, as well as the upper fibers acting as abductors and lower fibers adductors of the hip.

The superior fibers of the gluteus maximus are part of the lateral line of musculature (as described by Myers in “Anatomy Trains”) as it diverges at the hip, along with the gluteus medius and tenor fascia lata. This lateral line helps provide stabilization in the saggital plane, beginning at the peroneus longus and traveling ultimately to the splenius and sternocleidomastoid. From this perspective, we can view gluteal function during gait (ie closed chain) as rotators and abductors/adductors of the pelvis and an extensor of the torso

The gluteus medius and minimus attach proximally between the anterior and posterior gluteal lines and distally at the lateral surface of the greater trochanter for the former and anteriorly for the latter . They act as abductors and medial rotators of the thigh in open chain, and abductors and external rotators of the pelvis in closed chain,  the anterior fibers of the minimus and medius probably assisting in forward motion of he contralateral pelvis. Sahrmann states “the posterior portions of the medius act as abductors, external rotator and extenders of the thigh, with the anterior portion also assisting in hip flexion”.

The Glutes; they’re more than just another pretty muscle….

We are…The Gait Guys

There are 2 photos here (move your cursor over to the little triangle on the right to highlight the bar to toggle between photos)

Can you believe that an experienced runner would let a pair of shoes get this far on both sides.  This person does a few marathons a year and has been a patient of our for years…..he tends to milk out every last step in a pair of shoes but we had to hog-tie him and flog him repeatedly for going overboard this time. I bet there had to be 2000 miles on these puppies !  And get this…..he had no foot or knee pain ! (his response was, i saw the wear but i was not having any issues).

Can you imagine how far out side the contact line the knees had to be ? This has the old Nike Cesium beat by a long shot (they were rear foot posted varus by about 3degrees). Heck, this could be 20-25degrees varus !  There is no question that he is avoiding and rear or mid foot pronation……the dude is fixed in supination. 

OF clinical note, he has a fixed right hallux limtus (turf toe) so this likely helps him to avoid medial toe off and forcing dorsiflexion through the big toe joint……however, there are better strategies than this to avoid a hearty toe off !

It is amazing what the body can endure !  Take this as a lesson of what NOT TO DO !  keep the miles between 400-500 miles gang……there are only so many compression cycles in EVA foam before deformation occurs.  In this case there was both deformation and just pure and simple friction wear !

PS: this was an easy pick up clinically……he sat in the waiting room with the 55 gallon barrel set beside him ….the one that he had been carrying around between his knees to force this much rear foot varus !

Good Form video from Newton→

Great little video from Danny at Newton…….it doesnt matter what shoe you have if your technique is crummy. Here he demonstrates very well what good contact form is……..we like to say…..“land so subtle on the forefoot that it is a hair distance to kiss your heel to the ground before you push off…..if you remain high on your forefoot at contact you lose your shock absorption because the foot mechanics are more close to supination.”

Short discussion on the toe extensor muscles

We received a great question from a doctor active on our Facebook page (Thegaitguys PAGE, not our user portfolio, make sure you are on the “PAGE”)
Here was the comment:I do like the crouch gaits to help with proximal muscle activation. However I am still not sold on the long toe extensor activation. It would seem to me that the function of this muscle in close chain (ie gait) would be more to aid in pulli…ng the body over the talus (while keeping the toes fully anchored and wide) as opposed to extending the distal phalanx in an open chain fashion. While open chain exercises may ‘strengthen’ this muscle the neurological processing would seem to be different than closed chain and therefore the transfer to more dynamic exercises would be difficult.? I would think that it would not necessarily change the gait but instead allow for better compensatory strength and durability. Although I still have yet to develop a great exercise for this closed chain control. Any ideas?See More

10 hours ago · LikeUnlike

The Gait Guys when you activate the toe extensors the arch is increased from the windlass mechanism across the metatarsophalangeal joints. Raising the arch will help bring it to neutral since the crouched gait is a pronation challenge. give it a try…..…….try the crouch shuffles with toes down and toes up…..you will feel the increased demand on the anterior leg compartment, the greater awareness of the foot tripod esp the first metatarsal head anchor point and the improved ability to control the internal tibial spin (and pronation challenge( that occurs with shuffling with toes down. Remember, closed chain is not any more important that open chain activities……arm swing it gait is open chain but it is necessary…..leg swing is open chain but it is necessary for normal progression and pelvic/core use. also remember……we are a flexor dominant society…..look at how many of your clients toes have either a gentle flexion to them or significant…..the balance of the function across the metatarsophalangeal joint is necessary on balance of extensors and flexors……the shuffle gait with toes up is a huge challenge to the toe extensors……that feeling of the strain on the top of the foot and into the shin is confirmatory. OF course, you are right in what you said……but to get the toes optimally anchored you have to have enough long toe extensor strength to override the long flexor dominance…..otherwise you being hammering the toes and enter into the spiraling vortex of flexor dominance, lumbrical inhibition, short extensor overactivation, proximal fat pad drag etc.

Shoe Anatomy 101:

If you are truly to be a shoe geek, then you must be familiar with some “shoe anatomy.” Simply put, there is the sole ( the part that contacts the ground), the midsole (the part right between the sole and the last), the shank (the stiff rear part of the midsole), the last (the part on top of the midsole and where the insert or orthotic will sit), the insole (the removable insert), the upper (the part above the last that has the sides, laces, etc)the heel counter (the part that holds the heel in place), and the toe box.

Lets discuss each in turn

The Sole (also called the outsole)

This is the part of the shoe that comes in contact with the ground. It is usually made of rubber and provides for some degree of shock absorption and traction. For running shoes, it is usually cemented to the midsole.

Remember that the heel strikes the ground at approximately a 16° angle lateral from the center of the heel  (in a heel strike gait, no we aren’t condoning this, this is how shoes are designed).  The force is then transmitted from the sole of the shoe, up the lateral column of the foot and across to the first metatarsal for propulsion.  This can be assisted by a “rocker” which is a “drop” put into the front portion of some stiffer trail shoes, to ease walking and assist in toe off.  (This is good for people with Morton’s toes or hallux rigidus).

A flare to the sole of the shoe, particularly lateral can be important for stability on uneven surfaces.  A lateral flare provides extra stability upon heel strike, but it speeds up the rate of pronation.  This may be a bad thing, depending on your feet. This flare must extend the length of the sole, otherwise injury can occur at the mid tarsal joint as the foot comes through mid stance. A medial flare can help to prevent overpronation, as the foot comes through mid stance. Again, it must run the length of the shoe.

Look at the lugs on the sole. Are they beveled or straight? A straight lug or cleat will hold on to mud, whereas a beveled one will shed it. This is an important consideration if running off road. How about the cleat pattern (front vs. back and side to side)? Are they symmetrical or opposing? Opposing patterns will enable you to ascend and descend easier at the expense of a slight amount of speed.

The Midsole (sandwiched between the sole and upper)

Midsole material is very important, as it will accommodate to the load imposed on it from the person and their body weight. It serves as the intermediary for load transfer between the ground and the person.  Softer density material in the heel of the shoe softens the forces acting at heel strike and is good for impact and shock absorption. The stiffer the material, the more motion control.  Air is an excellent shock absorber, however it does not deform, it displaces. This creates and unstable surface for the foot, promoting ankle injuries. Foam and gel are much better as they transduce the force and dissipate it. Often midsoles are made with something called “dual density”.  This means that the midsole is softer on its lateral aspect, to absorb force and decrease the velocity of pronation during heel strike and midstance, with a firmer material medially that protects against overpronation as you come through mid stance and go through toe off.

The Shank (this can be within the midsole)

The shank is the stiff area of the shoe between the heel to the transverse tarsal joint. It corresponds to the medial longitudinal arch of the foot, provides torsional rigidity to this shoe and helps to limit the amount of pronation and motion at the subtalar and mid tarsal joints.

The Last (the part between the midsole and insole)

The last (look inside the shoe on top of the shank) is the surface that the insole of the shoe lays on, where the sole and upper are attached).    Shoes are board lasted, slip lasted or combination lasted. A board lasted shoe is very stiff and has a piece of cardboard or fiber overlying the shank and sole (sometimes the shank is incorporated into the midsole or last) .  It is very effective for motion control (pronation) but can be uncomfortable for somebody who does not have this problem.  A slip lasted shoe is made like a slipper and is sewn up the middle.  It allows great amounts of flexibility, which is better for people with more rigid feet.  A combination lasted shoe has a board lasted heel and slip lasted front portion, giving you the best of both worlds.

When evaluating a shoe, you want to look at the shape of the last (or sole).   Bisecting the heel and drawing an imaginary line along the sole of the shoe determines the last shape.  This line should pass between the second and third metatarsal.  Drawing this imaginary line, you are looking for equal amounts of shoe to be on either side of this line. Shoes have either a straight or curved last.  The original idea of a curved last (banana shaped shoe) was to help with pronation.  A curved last puts more motion into the foot and may force the foot through mechanics that is not accustomed to. Most people should have a straight last shoe. 

The Upper (the sides and top of the shoe)

This is the part above the midsole that holds your foot on the sole. It is usually made of nylon, Gore-Tex or some other man made material. Pick something light and breathable.

The Heel Counter (the back of the upper)

This is part of the upper. A strong, deep heel counter with medial and lateral support is also important for motion control; lateral support especially for people who invert a great deal or when you’re going to place an orthotic in the shoe which inverts the foot a great deal.  The lateral counter provides the foot something to give resistance against.  This needs to extend at least to the base of the fifth metatarsal, otherwise it can affect the foot during propulsion. A deep heel pocket helps to limit the motion of the calcaneus and will also allow space for an orthotic. The heel counter should grip right above the calcaneus, hugging the Achilles tendon.

The Toe Box

The toe box should be generous enough to prevent crowding and pressure on the metatarsal heads.  The widest portion of the shoe should parallel a line bisecting the metatarsal heads.  Excessive pressure can result in bunions and/or hammertoes.  The shoe may soften and break down laterally, but it will not increase in length.

When measuring feet and determining shoe sizes, do it both sitting and standing, because the laxity of ligaments can become very evident, especially when the foot is weight bearing or you have the weight of a pack on your back.  If the person has greater than one size of splaying in both length and width when going from one position to the other, go for the bigger size.  Always use ball length rather than sole length. People usually buy smaller shoes because when you pronate, there is less volume in the mid foot and a smaller size shoe will feel better.

The Insole (the removable inner footbed)

This is the part of the shoe that most people remove to put in an orthotic. They have come a long way in construction and make a big difference in shoe fit. They are usually made of some type of foam or EVA material. Some of the newer ones are even dual density foam.

Well, if you made it through this, you are officially as nerdy as us. We’ll see you in the shoe isle…..

 We remain, The Gait guys….

horse: walk, trot, canter, gallop
man: walk, jog, run, sprint….very similar
….amble…..well that is another story……horse “ambling” gaits, a collection of several other smooth footfall patterns that may appear naturally in some individuals but which usually occur only in certain breeds, and often require special training…….as for humans? hummm. time for some homework

" target="_blank">Why I run......amazing video→

thanks Kyle and Jason and Newton…….this one is what it is really all about……. “in life we dont have it all figure out, there are key moments that change your life forever”.

So…..to close out the week…..we put aside anatomy, biomechanics, physics, neurology, orthopedics, research etc……we put it all aside……..and give you the big picture…..

“why i run”………don’t miss this one……it just might pull a tear from your eye……Thanks Kyle and Jason…….

Today’s post is a very nice follow up to the one earlier in the week entitled “Materials: do soft soles improve running shoes?”……which also commented on client perceptions of the footwear.  We hope the shoe and R&D companies are paying close attention to the work were are making available here. 

__________________________________________________________

Today…..

Perceiving is believing

What you think matters! Perception of shoe cushioning seems congruent with what you believe.  If you THINK the cushioned shoe will be softer, you will probably perceive it as so, even though there may be little to no change in ground reaction forces. Most studies show cushioned shoes actually INCREASE impact forces.

McCAW, STEVEN T.; HEIL, MARK E.; HAMILL, JOSEPH: The effect of comments about shoe construction on impact forces during walking

Medicine & Science in Sports & Exercise: July 2000 - Volume 32 - Issue 7 - pp 1258-1264

journal link:

http://journals.lww.com/acsm-msse/Abstract/2000/07000/The_effect_of_comments_about_shoe_construction_on.12.aspx

conclusions as quoted in their article:

“Footwear designers incorporate a variety of midsole materials and mechanical systems to cushion shock while controlling rearfoot motion. To market shoes, advertising copy and the claims of salespeople often extol the benefits of the materials and design incorporated in a shoe. This marketing strategy is common, as evident from a perusal of a fitness magazine, in spite of a paucity of unbiased biomechanical testing of the validity of many of these claims, and a lack of understanding of how such claims may influence the gait behavior of a purchaser of a pair of shoes.”

It is vital to understand their next research finding from this study,

“The results indicated the impact ground reaction force varied as a function of the advertising message. When subjects were informed that a particular surface provided additional cushioning, impact ground reaction force data were higher (121% of body weight) than when subjects were provided with a warning message (110% of body weight). The results were interpreted as suggestive of subjects moderating impact in accordance with the expected cushioning of the material. That is, subjects were less inclined to use a landing strategy that would reduce impact force if they had been told that cushioning would be provided by the surface material. The study raises the question of how subjects would respond if the cushioning characteristics of a shoe, rather than a landing surface, were altered, because a shoe represents a more personalized aspect of the foot/ground interface.”

From their study they referenced Robbins and Waked:

“Robbins and Waked (15) demonstrated that subjects may be deceived into accepting higher forces during landing if provided with misleading information regarding the energy absorbing characteristics of the landing. Because of research suggesting a possible cause of lower impact peaks in harder shoes to be an intrinsic avoidance mechanism (1), it may be theorized based on expectancy theory that influencing someone to believe that one shoe can absorb more energy than another may result in different ground reaction force values. Contrary and sometimes confusing findings in the literature emphasize the need for further study in the area of perception and energy absorption. The purpose of this study was, therefore, to determine the effect of investigator comments regarding shoe construction on the ground reaction force measured during walking.”

This is an excellent article that seems to suggest that there is far more to it than the engeneering that goes into the shoe. That marketing and consumer assumptions are a part of how a shoe is used and works. 

Very interesting !  We hightly recommend you purchase this article here…..

http://journals.lww.com/acsm-msse/Abstract/2000/07000/The_effect_of_comments_about_shoe_construction_on.12.aspx

Shuffle Gait DVD

Varations of this crouch style gait (we call them shuffles) are a major staple in our gait and core and lower limb rehab and exercise progressions……after dozens of emails already in just an hour of this posting……we can see that we need to do a DVD on our gait progressions and Shuffle Gait variants…..as there are multiple variants to correct various problems…..we will do our best to get it out soon……it is now in the hopper.

Muscle contributions to support and progression during single-limb stance in crouch gait.

Steele KM, Seth A, Hicks JL, Schwartz MS, Delp SL. J Biomech. 2010 Aug 10;43(11):2099-105. Epub 2010 May 20.

What the Gait Guys have to say about this article:

We have long advocated the use of the “shuffle gait” exercise for increased gluteal activation (see Youtube clip entitled “the shuffle gait exercise”) and this paper provides further support for our recommendation.

Try this simple experiment. Stand on 1 leg. Now close your eyes and try and stay that way for 30 seconds, trying not to lose your balance, touch the ground with your other foot or steady yourself with your hands. Once you have regained your composure, with your eyes closed, extend our head (ie. Look up). Tough to balance, eh? So what just transpired?

3 integrated sensory systems enable us to remain upright in the gravitational plane: vision, the vestibular system and the proprioceptive system (joint/muscle mechanoreceptors). When you 1^st stood on one leg, you were utlilizing all 3 systems. When you closed your eyes you were eliminating vision from the equation. When you tilted your head back, you were taking out the lateral semicircular canals from the vestibular system, relying predominantly on the joint and muscle proprioceptors. Let’s guess that you probably need some work on your proprioceptors!

Placing someone in a crouched gait generally means you are at least partially flexed at the waist and need to extend your head somewhat to keep your eyes parallel with the horizon (the brain is wired to keep the visual axes upright and parallel). Extending your neck activates the local joint mechanoreceptors and more importantly, the muscle mechanoreceptors in the suboccipital muscles, which have the highest density of mechanoreceptors of any muscles in the body. These muscle mechanoreceptors feed information into the cerebellum and vestibular nuclei, which fire the antigravity extensor muscles that keep us upright in the gravitational plane. This includes muscles like the glutes, quads and lumbar erectors, just like in the study.

It was interesting that in crouched gait, the muscles which provided upward momentum (gastroc, soleus, quads) remained active throughout single leg stance. These are also stabilizers of the foot and placing the ankle in dorsiflexion (as in a crouch) increases the amount of pronation occurring (remember pronation is dorsiflexion, eversion and abduction); this requires additional stabilization (medial gastroc is an inverter, gluteus Maximus and posterior fibers of glute med control the speed of internal rotation of the lower extremity, along with vastus medialis).

Look to crouched positions as training tools when rehabbing gait, and don’t neglect the shuffle!

TED: how to tie your shoes ! →

not too technical to say the least…….but we are trying to make sure that we accumulate a library of just about everything gait, running, shoes, feet, movement, biomechanics related.

enjoy…….its a fun    3 minutes

Following the Flintstones….

In this next clip, Barneys barefoot technique has only improved marginally. He initiates with a much better forward lean. His ankle rocker is improved, but not enough for him to gain traction. His arm swing is better, but he has a tendency to hunch his shoulders. His leap into the car is a tribute to his gastroc soleus group…

Hey

Check out Barney joing the barefoot craze! We slowed him down a bit to observe his technique a little closer

Not the best barefoot technique we have witnessed. Though he has a some forward lean, he still heel strikes with an extended knee in front of his body (ouch!) and has little to no ankle rocker with premature heel rise. This results in a “bouncing” gait with most likely sore calves!

We hope Betty was a massage therapist…

graphic above by Edward Muybridge

Leg length discrepancies and heel lifts. To lift or not to lift…

The Gait Guys

Leg length discrepancies (LLD’s) are encountered on a daily basis. They are the root of many ankle, knee, hip and spinal problems. The questions the clinician must ask are “How much is significant?”, “How much do I add?” What are some of the signs and symptoms?” “What is the etiology?” and “How do I detect it?” A literature search (2003) provided the following information and answers.

How much is significant?

Most authorities claim that deficiencies of greater than ¼ inch (6mm) are clinically significant (1, 2) though some sources state that differences as little as 4 mm are significant (5). Subotnick (3) states that because of the threefold increase in ground reactive forces with running, lifts should be used with inequalities of greater than 1/8” inch (3mm).

How much do I add?

One of the easiest ways to determine the amount of lift needed is to examine the person in a weight bearing posture and add lifts under the short leg until the pelvis is even or until the lumbar spine is straight. If using off weight bearing measurements, you need to add 1/3 more height than measured because the talus is positioned 1/3 of the way between the calcaneus and metatarsal heads (4, 13). So, a heel lift placed under the calcaneus will only raise the talus 2/3 of that height. Lifts placed under the calcaneus can shorten the tricep surae muscles (4, 6) and apply increased pressure to the metatarsal heads (12); full length sole lifts are more physiological, though not always practical. Due to the supinatory moment of the short leg on heel strike, a lift may cause overcompensation and increased supination, with a tendency to overweight the lateral column and possibly injure the lateral ankle. Careful observation of gait post addition of a lift is in order and a valgus post running at least the length of the 5^th metatarsal along with the lift should be considered (8, 9). Heel lifts also cause EMG changes of leg muscles, with decreased recruitment of gastrocnemius and tibialis anterior directly proportional to the height of the heel lift (18, 19). A lift or LLD changes the ground reactive forces associated with gait, increasing vertical force on the longer leg, along with increased joint stresses along the kinetic chain (14, 20).

Generally speaking, lifts greater than 3/8” (9mm) require extrinsic modifications to footwear (4, 6, 8). Find a competent individual to perform this work for you. Large discrepancies should be treated gradually, at a rate of ¼ inch every 4 weeks, less if symptoms do not permit.

What are signs and symptoms associated with LLD’s?

Compensation comes in many forms, depending whether it is acute (recent injury caused an LLD or compensation resulting in one, or long term. The deficiency can cause injury on the short or long legged side (or both).

The long leg moves through a greater arc during all portions of swing phase (7). The person may flex the knee to compensate and shorten the arc. The individual may also maximally pronate and evert the calcaneus an additional 3 degrees or greater on that side in an attempt to lower the navicular to the ground and shorten that leg. This causes an increased amount of internal rotation of the tibia and thigh causing muscular dysfunction (tightness of the hip flexors, strain of the intrinsic external rotators from eccentric deceleration of the thigh), along with medial knee strain (especially with concomitant genu valgus) (4, 6, 8, 9, 10, 11, 21, 22).

The short leg side will often supinate in an attempt to lengthen and cushion some of the shock of heel strike, since it has a greater vertical distance to travel (14); this often occurs with hyperextension of that knee. This lessens the dampening ability of the knee (since it flexes almost 20 degrees between heel strike and full forefoot load), and speeds the rate of subtalar pronation (since the rear foot is inverted and still must pronate the same amount (4). Many individuals will try and attenuate impact by contracting the contralateral hip abductor muscles and eccentrically lower the shorter extremity (4, 14). This can produce excessive strain of that musculature (trochanteric bursitis) as well as pathomechanical abnormalities of the L4 and L5 motion segments (due to increased body rotation toward the short side and attachments of the iliolumbar ligaments; this can cause degenerative changes if present long term (11, 12)).

What’s the etiology?

LLD’s can be structural (anatomical) or functional (pathomechanics, compensation). LLD’s can be due to foot problems (overpronation/supination, fractures), leg or thigh problems (congenital shortening, deformity, fracture), or pelvic compensation (rotation of ilia, fractures).

So, what is the etiology? A lot can be gleaned from the history. Past trauma is the most obvious so pay close attention. This could result in flattening of the calcaneus or overpronation due to ligamentous laxity; tibial fractures can cause shortening as well as increased or decreased tibial torsion; similar findings can occur in the femur, along with anteversion or retroversion; pelvic trauma can be more subtle and x-ray can often provide the most information (1, 2, 4, 6).

How do you determine a leg length inequality?

There are a number of methods, each with their own merit. X –ray is most accurate, but exposes the patient to ionizing radiation. Weight bearing seems most appropriate, since symptomatology usually presents itself then. Supine measurements are said to be influenced by asymmetrical muscle tension, table pressure on the innominates and hip flexor length (15).

With the patient weight bearing and both feet placed below the trochanters, observe the level of the medial malleoli. Next, compare the heights of the tibial plateaus. Femoral length can be judged by the heights of the greater trochanters, and pelvic alignment judged by the heights of the iliac crests (4, 17).

Alternately, lay the person supine and observe the heels and medial malleoli. If there is noticeable discrepancy, they may have a short leg; if there isn’t, they still may have a discrepancy that they are compensating for. Check the range of motion of the foot and ankle in 6 general directions: plantar flexion (40-45 degrees), dorsiflexion (20-25 degrees, depending on whether the knee is flexed or extended), inversion of the forefoot (3-60 degrees, on average), and eversion of the forefoot (20-45 degrees on average), calcaneal inversion (4-20 degrees) and calcaneal eversion (4-10 degrees). Excessive calcaneal eversion usually means over pronation due to a longer leg on that side; excessive inversion can mean a long leg due to a cavus foot type (2, 4, 6, 8, 9, 12). Lack of flexibility in the posterior compartment of the calf usually causes a greater degree of pronation (16).

Now, perform Allis’s test. Bend both knees to 90 degrees and observe the height of the tibial plateaus. The lower one is usually the side of the discrepancy (which can be in tibial length or due to excessive pronation). Now walk superior to the knees and observe the femurs from more cephalad (4). Is there a discrepancy? If so, the problem may be in the femur length, femoral head angle or pelvis. Extend the knees so that the legs are lying flat on the exam table. Palpate the greater trochanters on both sides. Is one lower than the other? If so, they probably have coxa vara on the short side or coxa valga on the long side. If they are even, you need to look at the pelvis. Does one ASIS palpate more anterior or posterior than the other? This could represent compensation. A posterior or “flexed” ilia, usually causes a short leg on that side; an anterior or extended ilia usually causes a long leg on that side. Now stand the patient up and perform a Gillet Test. Have them stand erect and hold onto something for balance. Palpate the PSIS on one side along with the 2^nd sacral tubercle. Have them raise their thigh to 90 degrees on the side you are palpating. The PSIS should nutate backward (flex) and drop .5-1.5 cm on the side of the raised leg. Now have them raise the opposite leg. The sacrum should nutate backward and down. If either of these movements does not occur, consider pelvic pathomechanics and treat accordingly. Recheck for motion as well as leg length when done.

Standing observation often (but not always) reveals overpronation on the long leg side and relative supination on the short leg side. The shoulder is often higher on the short side and the waistline dips to the long side because of posterior rotation of the innominate. The shoulder will dip to the side of the short leg on heel strike during dynamic evaluation (4, 6, 8, 9, 10, 11). Gait observation usually reveals adduction of the pelvis toward the stance phase leg with a lateral sway in excess of 1” during stance phase. The person will seem like they are “stepping into a hole” on the short side.

Conclusion

Leg length inequalities occur due to a variety of anatomical and physiological conditions. Careful analysis and examination can often reveal its etiology. To lift or not to lift is a clinical decision that is left to the clinician and patient, with a careful balance between what is perceived as improved biomechanics and tolerance levels of the patient with regards to their presenting symptomatology.

References available by request

Materials: Do soft soles improve running shoes ?

BioMechanics
April 1998
Materials: 
Do soft soles improve running shoes?
Most athletic shoes advertise injury protectiong through “cushioning,” but real world studies have not shown impact moderation.
By Steven Robbins, MD, Edward Waked, PhD, and Gad Saad, PhD

here are their conclusions word for word:

Please honor the authors and purchase the article for your own use.

Conclusion
“Shoes with cushioning fail to absorb impact when humans run and jump, and amplify force under certain conditions, because soft materials used as interfaces between the foot and support surface elicit a predictable reduction in impact-moderating behavior.5-10,13-17 This behavior is not a response to sensations directly caused by impact because, whereas barefoot humans estimate impact precisely, humans judge it inaccurately when shod.14-17 This situation has recently been made clearer. Reduction of impact-moderating behavior is a response to loss of stability induced by soft-soled cushioned shoes: Humans reduce impact-moderating behavior in direct relation to increased instability.27 This is presumably an attempt to achieve equilibrium by obtaining a stable, rigid support base through compression of sole materials.27
After considering footwear advertising, additional factors appear to influence impact-moderating behavior. Recent reports also indicate that humans reduce impact-moderating behavior, thereby amplifying impact, when they are convinced that they are well protected by the footwear they are wearing. Advertising that suggests good protection results in higher impact, whereas advertising that suggests injury risk attenuates impact.19 Deceptive advertising, suggesting that expensive cushioned footwear offers advanced technology that protects against impact, accounts for the 123% greater frequency of injuries with the most expensive shoes found by Marti.18
Public health could be advanced through truth in advertising of footwear products with cushioned soles. Furthermore, footwear must be required to provide good balance. Current athletic footwear undoubtedly causes falls, since footwear with thick yielding soles destabilizes humans by as much as 300% compared with hard-soled shoes.
Now that the destabilizing nature of cushioned footwear is well established, continued manufacture of these hazardous items without explicit warning labels represents risk for liability claims from users who are injured from falls and ankle sprains while wearing them. In the context of this report, footwear that provides superior balance will probably be effective at attenuating vertical impact. Clearly, highly resilient materials must be removed from shoe soles for many reasons. This move will portend better health through improved stability and fewer injuries from excessive repetitive impact in sports. ”

Run, Carey, Run?

Lets look at this Hitchcock classic “North by Northwest” and check out Cary’s form.

1^st of all, what an arm swing! Think of all that energy it is sapping from the rest of his muscular system. He must be hiding something, but what? We can only see him from the waist up, so we may never actually know. Did you notice how he initially only turns to the right? Did you pick up on the flexion at the waist? How about that torso bob from side to side? Not much to his hip abductors now are there?

The only thing he has going for him is he is wearing leather soled shoes, which have been shown to have one of the lowest impact loading on the body (yes, you read that right; increased cushioning INCREASES impact forces, but that’s not what we are here to talk about). Oh yea, he actually impacts the ground at the end of the sequence. I guess if his technique was better, he would have hit even HARDER.

Next sequence, we are off to a good start, look at that forward lean to start! This is essential to good technique. He loses that form pretty quickly; we can still see that forward flexion at the waist; certainly costing him energy by not using his core.

Finally, we get a posterior view at the end, but the uneven surface makes it difficult to make an analysis.

We think Cary would certainly give Lola a run for her money. Cary, next time, engage your core and watch your step…

We Remain….The Gait Guys

Chicago Lecture , "World Class Shoe Fit"

Yesterdays IRRA event (Independant Running Retailers Assoc) lecture in Chicago went 2.5 hours yesterday ! Great group, great feedback. We talked at length about shoe anatomy and the various anatomic foot types and how to evaluate a client or patient for a good shoe match and fit depending on their foot type.  Everyone, please welcome aboard another 60 foot/shoe/gait nerds ! The more the merrier !