Retail Focus: The Midsole

The Midsole is the area sandwiched between the out sole and the upper (or vamp, as we have learned).

The two jobs of the midsole are to provide some degree of shock absorption as well as torsional rigidity to a shoe.

Midsole material (usually EVA or similar 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 serves to soften the forces acting at heel strike (hopefully NOT when running) and “feels” good for impact and shock absorption. We know from studies we (and you) have read (and posts we have posted) that this is largely perception, as softer midsole materails generally INCREASE impact forces.

The stiffer or denser the midsole material, the more motion control it will provide. This is one of many “motion control features” put into shoes.  Some shoes have two different density foams (called dual density midsoles (see pictures above)), to provide a more graduated resistance. The midsole is softer on its lateral aspect, to absorb force and decrease the velocity of pronation during heel strike and midstance (ie. it keeps you supinated a bit longer), with a firmer material medially that protects against overpronation as you come through mid stance and go through toe off.

Air is an excellent shock absorber, however it does not deform, it displaces. This creates an unstable surface for the foot, promoting ankle injuries. It is great for tires, but we feel does not have a place in shoes. Can you think of any shoes that have Air in the midsole? We can, we have all heard that brilliant marketing campaign.  Foam and gel seem to be much better as they transduce the force and dissipate it.

What’s the bottom line? Materials determine the flex and to some degree, the shock absorbing characteristics of the shoe. More rigid midsoles provide more motion control, less rigid ones less. Not everyone can go into minimalist shoes, and not all need control. But we all need educated.

Want to know more? Take our soon to be released course “Proper Shoe Selection” or better yet, our entire shoe fit course, so you too can be a Shoe Jedi!

Shoe Jedi Masters….The Gait Guys

Make sure you visit our Youtube channel: The Gait Guys, or follow us on Facebook and Twitter

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Video Gait Case: It is Neuromechanics Wednesday.

* Remember: you can always click on the YOUTUBE logo in the bottom right corner of the video to be hyperlinked to a blown up version of the video on youtube.  Just remember to read what we have written here as well. 

Here we present a video case of a client with advancing spinal myelopathy with characteristics of Trendelenburg gait pathology. Be patient with the first few slides, we have to set up and teach about the important issues regarding the topic and case otherwise some folks will get lost.  There is much to this case. There is evidence of balance issues (dorsal column disease), limb circumduction, 5 point turning strategy (abnormal), pathologic arm swing changes and a few other issues to observe. If you are looking for a great gait case that covers several layers, this is a good one. Be sure to check our our blog, youtube channel and website for other great videos and teaching cases.

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Lean on me…

More on short legs…

We remember from last week, there are several common compensations for a short leg.

We recounted six common adaptations and spoke about pronation of the longer side, and supination of the shorter side last time. Here are the others, in case you need a reminder:

•  lean of torso to the short leg side
• circumduction of the longer leg around the shorter
•  hip hike on long leg side (seen as contraction of hip abductors, obliques and quadratus  lumborum on short leg side)
• excessive ankle plantar flexion on short side
•  excessive knee bend on the long leg side

Lets look at “The lean”. Leaning to the short side helps to create clearance for the longer leg. The lean in essence helps to lift the pelvis on the swing side by using a shift body mass to the stance leg, similar to in a Trendelenburg gait. It makes no difference if the leg is functionally or structurally short, the body still needs a strategy to move around the asymmetry. The lean can often be mistaken for a weak gluteus medius on the side they are leaning to (which would look very similar). Sometimes, the two can occur concurrently as well. 

Often with “the lean” there will be an increased arm swing on the opposite side to “help” pull the long leg through , while creating a counter balance effect.

Watch the above video several times to see what we are talking about. This person has a left short leg and leans to that side. We slowed it down so it is easier to see.

Again, the thing to remember here is that what you are seeing is the compensation, not necessarily the problem. When one leg is shorter, something must be done to get the longer leg through swing phase.

Short legs and compensations. There not just for breakfast anymore.

Ivo and Shawn. Two guys with two short legs… ; )

Education’s purpose is to replace an empty mind with an open one.

Malcolm S. Forbes

More on children's foot maturation.

source article: http://www.ncbi.nlm.nih.gov/pubmed/21244647

Watch what you put on your kids feet! encourage them to go barefoot early or use a minimal support type shoe (like Robeez or similar with a soft leather sole)
“Shoes affect the gait of children. With shoes, children walk faster by taking longer steps with greater ankle and knee motion and increased tibialis anterior activity. Shoes reduce foot motion and increase the support phases of the gait cycle. During running, shoes reduce swing phase leg speed, attenuate some shock and encourage a rearfoot strike pattern”.

Effect of childrens shoes on gait: a systematic review and meta analysis J Foot Ankle Res. 2011 Jan 18;4:3.

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A fun little video for all you foot fanatics out there!

Have a great Weekend.

Ivo and Shawn

OK, Friday Follies are upon us. Here’s a not so funny one. Funny Gait May Cause Back Pain. Gee, imagine that! : )

We don’t necessarily agree with the Journal of the American Podiatric Association that orthotics are the answer, but the we like the premise.

Have a great Friday!

Ivo and Shawn

photo from: http://www.fatfiction.co.uk/society/funny-walks-of-the-20th-century/

Is that dry skin on your feet ? Lotions not working ? It is a yeast infection !

How many times will you smash your forehead into a wall before you realize that the bleeding suggests it might not be a good idea to continue ?

Similarly, how many times are you going to put lotion on your feet, or pumice off the dry skin and callouses before you ask “maybe this isn’t dry skin after all !” ?

Do your feet have something similar as to what is seen in the photo above ? Do your heels look like this ? Do they have the deep fissured cracks ? Do you have similar powdery white appearing stuff on your feet ? Are lotions not taking care of all this “apparently dry” skin ?

Candida albicans is a yeast that lives in harmony in and on our body until something throws off the delicate balance, causing the fungus to proliferate wildly. When Candida is allowed to build up in the body, over time a wide variety of severe symptoms can occur. Without proper treatment, the yeast overgrowth can be extremely dangerous.

Candida buildup in any one place in or on the body indicates that a balancing act is off when it comes to normal body system regulation. Candida overgrowth can cause cognitive problems, genitourinary, gastrointestinal, allergic and even (as we see here) dermatological problems. The skin is the body’s largest organ and it is also susceptible to problems.

Sometimes referred to as Athletes foot, in this case a fungus, it spreads easily through contact. Exposure to the fungus does not guarantee its growth and conditions must be right for the fungus to spread. Athletes foot is a fungal infection of the skin of the feet, which can also involve reactions by the feet and skin to toxins produced by candida/fungus overgrowth.

• Red and/or pale skin.
• Mild to intense itchiness, mostly in between the toes.
• Burning and inflammation.
• Cracked or blistered skin.
• Skin patches and scaling of the skin.
• Skin fissures (small cracks).
• Toenails may become affected as athlete’s foot progresses causing thick yellowish nails that are malformed, thickened and crumbly, called onychomycosis.
• Fingernails can also become affected just like toenails.

Fungus on the feet can also develop into or enable other opportunistic issues such as calluses, corns, warts, and horny growths, or keratotic tissue (hardened horny growths or build-up). Active growth of the fungus is also supported by nutrients contained in such horny growths.

Now do not dismiss this apparently benign problem. We have had patients experience bleeding from these deep fissures and cracking and we even had one client have one of these bleeding fissures get infected with Staph Aureus and almost lose their entire leg from the “flesh eating bacteria”. So we do not take this apparently benign infection lightly and we suggest you not either.

Find a doctor that will properly diagnose the problem and then look deeper for signs and symptoms that indicate where in the body the imbalance is located. We have found it is usually a GI (gastrointestinal) tract problem, one of dysbiosis (normal flora imbalance) in the bowels.

Yeast and fungal infection, they are definitely not just for athletes alone.  If you have it, it is in all of your shoes, on your shower floor, and anywhere it can harbor growth. But do not freak out. Just take care of the problem and move on. It is a mere several weeks to months to remedy. Just get the right solution for the job.  When it comes to yeast we suggest 2% miconazole cream (yes, vaginal yeast cream) be trialed, but it isn’t a fix if that is not the problem.  See someone who knows. Sadly the yeast problem is missed by most in the field, we have no idea why but it is.

Shawn and Ivo…….not just your regular foot geeks. 

Read more: Signs & Symptoms of Candida Buildup in the Human Body | eHow.com http://www.ehow.com/list_5929515_signs-candida-buildup-human-body.html#ixzz1voZ6mLOw

If you can understand this type of complex footwork gait then running foot strike is going to be child’s play. 

“It (music) allows you to think in a way that you used to not think, and it also trains a lot of other cognitive facilities that have nothing to do with music.”-Limb

Gait and Biomechanics and Love Potion #9 !

The topic today is the brain and human movement and music. We would like you to enjoy this video we chose today of Slavik and Anna a little differently that you would normally watch a video. We ask that you cover up the top half of the video with your hand or a thick piece of paper so that you can ONLY see their legs and feet. Trust us, the hands, arms and their youthful attractiveness will distract you from the amazing stuff going on down in the legs and feet. Go ahead now and watch the video and see the amazing skill and precision of complicated foot work. There will be times that the feet are a blur, you will think the video has been sped up. It has not. If you can understand this type of complex footwork gait then running foot strike is going to be child’s play. It is why we study this stuff, because everything after this is easy. These are two of the very best dancers of all time and they show it here. This video is a classic example of complex motor tasks combined to music. Music makes everything better. Weddings, parties, even elevators (usually) are better when there is music. Today we will discuss how the brain can use music to help us learn. If you know this next song, you may find yourself immediately humming it in your head …

A B C

Easy as 1 2 3

Or simple as Do Re Mi

ABC, 123, Do Re Mi, baby you and me

There you have it. The chorus to The Jackson 5’s song “ABC”.

Kids have always learned well and fast (such as the alphabet) when music is integrated into a concept. Music provides timing. Music taps into fundamental systems in our brains that are sensitive to melody and beat. And when you are learning a task, timing can access part of the brain to either make it easier, easier to remember, or engrain the learned behavior deeper. When you add music to anything you are exercising other parts of your brain with that task. It is nothing new in the world of music and brain research when it comes to proving that music expands areas of learning and development in the brain. As Dr. Charles Limb, associate professor of otolaryngology and head and neck surgery at Johns Hopkins University states “It (music) allows you to think in a way that you used to not think, and it also trains a lot of other cognitive facilities that have nothing to do with music.”

Several weeks ago we asked you as an athlete, and this pertains to runners and even those walking, to add music to your training. If you are walking, vary the songs in your ipod to express variations in tempo. Use those tempo changes to change your cadence. If you are a runner, once in awhile add ipod training to your workouts and do the same. Your next fartlek (a system of training for distance runners in which the terrain and pace are varied to enhance conditioning) might be a new experience. Perhaps an enjoyable one. Trust us, we have done it. Here at The Gait Guys, with our backgrounds in neurology and biomechanics amongst other things, we are always looking for new ways to learn and to incorporate other areas of brain challenge to our clients. To build a better athlete you have to use training ideas that are often outside the box.

Today’s video of Slavik and Anna is a classic example of complex motor tasks combined to music. It is much about timing. Dancers call it musicality. Asking anyone to learn these movements without music would not be impossible, it would take some time, but without a focus on perfect technique or music timing to the movements someone might be able to learn them crudely in a day or two. BUT, add the timing and musicality and accentuations to that music, such as Slavik and Anna show here, and this becomes a task of many many years study and practice. A task they make appear simple, elegant and fun to do or watch. Can you imagine the foot skill and core abilities of these two ? It is mind boggling the number of complex motor tasks that occur here every second.

So, go grab your iPod and go for a run or a walk. Mix up your songs. Hear the beat, feel the rhythm and change your next workout into “feeling” the change of the music’s embedded metronome. Use those advanced areas of your brain to integrate music and timing into your rehab, your run, your walk, your workout. Don’t just “listen” to the music. Rather, feel it, move your body to it, so your brain can integrate it and embed it and make your task more engrained. Remember what Dr. Charles Limb said,

“It (music) allows you to think in a way that you used to not think, and it also trains a lot of other cognitive facilities that have nothing to do with music.”

Shawn and Ivo……helping you push the edges of human performance, through science, music and medicine.

(And here is a thank you “shout out” to my dance instructors (Godiva, Brittni, Max, Jake, Vance, Ellie, Caleb and Michael) for helping me to understand, struggle, and learn about these complex foot, limb, core motions and how music changes the brain’s learning curve. It has taken my understanding of human movement, functional anatomy and biomechanics to a level that I never knew existed. Thank you !)

Attached here is an article from CNN and Dr. Limb that inspired today’s blog post.

http://www.cnn.com/2012/05/26/health/mental-health/music-brain-science/index.html

There is more than one way around a long leg…..
or…There are many compensations for a short leg

The 1st in a series…

You have heard us speak on LLD’s (leg length deficiencies) in previous posts here, here and here; but how about the compensations? What will you see visually?

We count about six common adaptations:

•  pronation of longer side, supination of shorter side
•  lean of torso to the short leg side
• circumduction of the longer leg around the shorter
•  hip hike on long leg side (seen as contraction of hip abductors, obliques and quadratus  lumborum on short leg side)
• excessive ankle plantar flexion on short side
•  excessive knee bend on the long leg side

The thing to remember here is that what you are seeing is the compensation, not necessarily the problem. When one leg is shorter, something must be done to get the longer leg through swing phase.

Lets look at the pronation/ supination scenario:

We often (but not always) see increased pronation on the longer leg side, in the bodies attempt to shorten the extremity. This is often accompanied by posterior rotation of the ilia on that side, resulting in saggital plane imbalances. This, of course, puts the external and internal obliques, as well as quadratus lumborum on that side in a shortened position, decreasing their mechanical efficiency. This all contributes to a loss of hip extension and usually, a loss of ankle rocker.

How about transverse plane changes? The lower extremity spins internally which places the vastus lateralis in a position of mechanical advantage, and the gluteus maximus and middle and posterior fibers of the gluteus medius in lengthened position, decreasing their efficiency, while placing the anterior fibers of the medius and minimus in a position of increased mechanical advantage. These changes will often contribute to changes in the frontal plane, often causing a “shift” to one side during walking and running gait.

Frontal plane dysfunction will be determined by the degree of functional leg length discrepancy created, along with how the other compensations are playing out.

Wow! Really, six compensations for a short leg? There are many more, these are only the most common ones we see. You probably see others in your analysis we haven’t mentioned here.

Stay tuned for more on this subject in future posts!

We are THE Gait Guys. Not set on world domination, just foot and gait literacy…

Phidippides cardiomyopathy, a condition caused by chronic excessive endurance exercise.→

In 490 BC, Phidippides, a young Greek messenger, ran 26.2 miles from Marathon to Athens delivering the news of the Greek victory over the Persians, and then he collapsed and died. This is probably the first recorded incident of sudden death of an athlete.

ScienceDaily Article LINK (June 4, 2012) —

“ Micah True, legendary ultra-marathoner, died suddenly while on a routine 12-mile training run March 27, 2012. The mythic Caballo Blanco in the best-selling book, Born to Run, True would run as far as 100 miles in a day. On autopsy his heart was enlarged and scarred; he died of a lethal arrhythmia (irregularity of the heart rhythm). Although speculative, the pathologic changes in the heart of this 58 year-old veteran extreme endurance athlete may have been manifestations of "Phidippides cardiomyopathy,” a condition caused by chronic excessive endurance exercise.  “

See the rest of the article via the links provided.

More is not always better for some folks.

Get your heart checked yearly if you are an endurance athlete and watch for the signs you may have issues. Sadly the most consistent sign of Phidippides cardiomyopathy is sudden death.  So it is kinda hard to get ahead of the signs ! Be sure there is not a family history of Marfan’s type disorders that can affect the integrity of the artery walls amongst other things (clue: are you tall, skinny, long fingers and toes, abnormally formed sternum/protruding or sunken chest, loose jointed, loose skin, eye problems ?) If you have any of the following symptoms get checked out immediately:

• chest pain
• fainting
• dizziness
• chest palpitations
• fatigue
• shortness of breath (excessive or prolonged)

In closing we are going to paraphrase the Science Daily article one more time:

"Although it has been recognized that elite-level athletes commonly develop abnormal electrocardiograms and atrial and ventricular entropy, these adaptations traditionally have not been thought to predispose to serious arrhythmias or sudden cardiac death. However, it now appears that the cardiac remodeling induced by excessive exercise can lead to rhythm abnormalities. Endurance sports such as ultramarathon running or professional cycling have been associated with as much as a 5-fold increase in the prevalence of atrial fibrillation. Chronic excessive sustained exercise may also be associated with coronary artery calcification, diastolic dysfunction, and large-artery wall stiffening.”

It is important to remember, just because you are not having any symptoms or signs does not mean you are free of risk either.  Train wise, rest and recover and remember “everything in moderation”. When you know you are at an imbalance in your training, your risks may increase. And remember, this disorder takes years to develop so a clean slate exam now doesnt mean you are risk free forever.

RIP Micah. 

Shawn and Ivo……. not trying to scare anyone…….but an informed athlete is a smart runner and alive.

Gait and Ovulation…A sexier saunter…

Welcome to Monday morning folks. Here’s something to get you going for the week. Nope, not a post about orangutans, but even BETTER!

Remember, you probably saw it here 1st. You always wondered (at least we did) why women walk differently around the time of ovulation (yes, they REALLY do) , and now here’s the proof. A recent article in Gait and Posture confirms that women walk slower and with what is judged to be a “sexier” gait around ovulation (Go Zsa Zsa Gabor!), which is believed to reinforce their attractiveness and make them more likely to be noticed and attract a partner.

We knew there was a reason we liked gait so much…..

Ivo and Shawn. Bald. Middle aged…Good looking…The Gait Guys

If you know, recognize that you know,
If you don’t know, then realize that you don’t know:
That is knowledge.

Confucius 

True knowledge is when one knows the limitations of one’s knowledge.

Neuromechanics on Saturday?

We have long been talking about the importance of the cerebellum in gait and motor activity (see here).

Here is a study (Non-Invasive Brain Stimulation Shown to Impact Walking Patterns) that looks at a new technique for using electrical stimulation of the brain’s cerebellum (trans cranial direct current stimulation to be exact) to change gait on a split belt treadmill (a double treadmill where each leg moves a slightly different speed). The study found that during the electrical stimulation the anode (negative charge) seems to speed up the learning process (our theory: more electrons, possibly creating a temporary electrical gradient which depolarizes (excites) the cells to a greater degree). And the cathode seemed to slow things down (our theory, it hyperpolarizes the cell and makes it less excitable).

Take home message? There are new neurologic studies and experiments that may be proving helpful in retraining gait function.  Stimulating the brain’s cerebellum seems to speed up learning or slow it down, depending on your client’s needs. We are sure we will be seeing more of this kind of stuff at technology advances. 

Maybe Larry Niven wasn’t that far off. (We loved the story “The Long Arm of Gil Hamilton”).  This could be a great, non invasive tool for rehab (or maybe improving performance!)

The Gait Guys…taking you deeper down the rabbit hole…

A silent parody of something we see in our offices all the time….Cruel Shoes..

Have a great Friday!

Ivo and Shawn

Arm swing in gait and running. Why it is crucial, and why it must be symmetrical.

It becomes clear that once you get the amazing feats seen in this video out of your head, and begin to watch just the variable use of the arms that you will begin to appreciate the amazing need for arm swing and function in movement.

We have written many articles on arm swing and its vital importance in gait and running. Have you missed all these articles ?  If so, go to our blog main page, type in “arm swing” in the search box and you will have a solid morning of readings at your fingertips.  We are still not done writing about this most commonly forgotten and overlooked aspect of gait and running analysis, and we probably never will be done.  Why is no one else focusing on it ?  We think it is because they do not see or understand its critical importance.

Without the presence and use of the arms in motion things like acceleration, deceleration, directional change, balance and many other critical components of body motion are not possible.

What is perhaps equally 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.”

is 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. As spine pain presents, the free flowing pendulum motions of the upper and lower limbs becomes reduced to dampen the torsional “wringing” on the spine. When this anti-phase is reduced then arm swing should be reduced. The central neural processing mechanisms do this to reduce spinal twisting, because with reduced twist means reduced spinal motor unit compression and thus hopefully less pain. (Yes, for you uber biomechanics geeks out there, reduced spine compression means increased shear forces which are favorite topics of many of our prior University instructors, like Dr. Stuart McGill). The consequence to this reduced spinal rotation is reduced limb swing.  And 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 still requires 12 % more metabolic energy.  Among measures of gait mechanics, vertical ground reactive moments are most affected by arm swinging and increased by 63% without arm swing.”

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.

In past articles we have carried these thoughts into historical functional needs of man such as carrying spears and of modern day man in carrying briefcases.   Today we show a great high functioning video of another parkour practitioner.  Parkour is a physical discipline and non-competitive sport which focuses on efficient movement around obstacles.  Watch closely the use of the arms. The need for arm use in jumping, in balance, in acceleration etc. It becomes clear that once you get the amazing feats seen in this video out of your head, and begin to watch just the use of the arms that you will begin to appreciate the amazing need for arm swing and function in movement.

There is a reason that in our practices we treat contralateral upper and lower limbs so much.  Because if you are paying attention, these in combination with the unilateral loss of spinal rotation are the things that need attention. 

Yup, we are The Gait Guys….. we have been paying attention to this stuff long before the functional movement assessment programs became popular.  If you just know gait, one of the single most primitive patterns other than crawling and breathing and the like, you will understand why you see altered squats, hip hinges, shoulder ROM screens etc.  You have to have a deep rooted fundamental knowledge of the gait central processing and gait parameters. If you do not, every other screen that you put your athlete or patient through might have limited or false leading meaning. 

Shawn and Ivo …  combining 40 years of orthopedics, neurology, biomechanics and gait studies to get to the bottom of things.