Well, how convenient. A fantastic picture for teaching from the cover of one of our favorite magazines.

For this post, lets start with the gal on the left in the pink shirt. 1st of all, she is running in flip flops. Since these require so much long flexor activity to keep them on, not the best footwear choice, in our opinion. Check out that exaggerated left sided arm swing. This goes to propel herself forward. Why the extra effort? Check out her right (stance phase leg). What do you see? The knee points outward while the foot is planted. We are looking at either external tibial torsion or a femoral retrotorsion. Did you pick up the compensatory head tilt to the left? The vestibular system has become involved, and the trapezius and levator scapula seem to be it’s target (thus the shoulder hike and ipsilateral rotation), as well as the ipsilateral lateral benders and rotators of the cervical spine, namely the splenius cervicis and capitis (the multifidus/rotatores are contralateral rotators).

How about the subtle pelvic shift to the right? and the mild crossover gait (note the adduction of the left knee across midline).

It would be great to see a shot of her barefoot to see what changes, as increased long flexor activity has both local (impaired ankle rocker, excessive forefoot inversion, reciprocal inhibition of the anterior compartment muscles of the lower leg) as well as long distance (namely increased flexor drive to the brainstem and cerebellum) implications. We would want to see this (as well as examine her) before making any recommendations other than LOSE THE FLIP FLOPS GIRLFRIEND.

Wow, all that and we have only scratched the surface.

We remain the geeks of gait: Ivo and Shawn

Activation, Cortical Remapping and what you are doing wrong to your people.

We are getting ready to step back into the studio to record podcast 58. We have been touching upon this topic off and on in the last 2 podcasts and we are going back in for more on pod #58 because this stuff is just too important not to beat it to a further pulp.  

The gist of this article is that cortical remapping occurs with injuries that are not 100% resolved. Lots of coaches and trainers out there are trying their hands at muscle “activation” and other new trendy tricks and they are missing the boat and making people worse if they are not doing a good sound clinical history and examination. You can activate any muscles and get what appears to be a miracle response, we can teach a 8 year old how to do activation and get a miracle response, but is it the right response or have you created a temporary compensation for your client (right before you send them into training or competition) ?  Activation is a 2 way street, there is the input into the brain and a corresponding motor output. If you are just rubbing out some muscles and get a stronger muscle test afterwards, and that is as far as your thoughts go before you turn your athlete loose, then you are a liability in the system. Are you part of the problem or part of the solution ?

Here are 2 paragraphs from this brilliant article. This is worth your time. As a client adapts to their unresolved, partially resolved (yes, even 95% is unresolved) injury(s) a secondary cascade of neurological changes ensue that often force new cortical remapping.  A remapping that is not as fundamentally safe or as sound as the pre-injury mapping yet one that is necessary for protecting further or other injuries. Yet, because it is not the original pristine pattern, it is also one that can begin undercurrents to corrupt other patterns of stability, mobility and movement in cortical and subcortical mappings. Understanding cortical excitability is important, and it can work for you and your client or against you both. It can be used for good or evil.  

If after you read these 2 paragraphs taken from the Alan Needle article in LER (link) you think you might be part of the problem or realize that you are not the magician you think you are, then good, you are on the track to self enlightenment and actually helping people.  Go read Alan’s article and breathe deep, ready to absorb and start yourself into understanding that you are really fixing the brain and not always the muscle, and that means you are gonna have to learn about the brain and how it works and more so how it can deceive you and your client and your training, treatments or therapy.

Come join us on The Gait Guys podcast 58 later this week as we delve into this topic deeper and more broadly.

Shawn and Ivo

PS: nice article Dr. Needle. Thank you !

http://lowerextremityreview.com/article/the-brain-a-new-frontier-in-ankle-instability-research

“Recently Wikstrom and Brown proposed a hypothetical cascade of events that would affect an individual’s ability to “cope” following an ankle sprain and provide a rationale for the varying contributors to instability. For an individual starting from a point of normal function, a lateral ankle sprain will trigger a consistent pattern of changes to the joint from the inflammatory process. Swelling will increase pressure on the joint’s mechanoreceptors, and pain will contribute to inhibition of the reflexes to the joint (arthrogenic inhibition). Together, this means patients will have difficulty sensing the joint and subsequently stabilizing it while excessive mechanical laxity will increase this loss of stability.19

Inflammatory changes may be similar across all patients; however, as symptoms remain and the patient adapts after his or her injury, a secondary cascade of neurological changes may occur that may include cortical remapping. In some patients, these adaptations may be beneficial and serve to protect the joint from further injury. Other patients may maladapt, as sensorimotor reorganization changes the nervous system’s perception of the joint. Variable amounts of laxity, proprioception, and cortical excitability exist throughout populations of healthy, previously injured, and functionally unstable joints. Where these populations diverge may be related to how each is scaled relative to the others. For instance, a joint with greater amounts of laxity may have higher proprioception and excitability to aid in stabilizing the joint, but following injury, these factors may become decoupled, leading to errors in movement and coordination.19”  -Alan Needle, PhD

 

Activation, Cortical Remapping and what you are doing wrong to your people.

We are getting ready to step back into the studio to record podcast 58. We have been touching upon this topic off and on in the last 2 podcasts and we are going back in for more on pod #58 because this stuff is just too important not to beat it to a further pulp.  

The gist of this article is that cortical remapping occurs with injuries that are not 100% resolved. Lots of coaches and trainers out there are trying their hands at muscle “activation” and other new trendy tricks and they are missing the boat and making people worse if they are not doing a good sound clinical history and examination. You can activate any muscles and get what appears to be a miracle response, we can teach a 8 year old how to do activation and get a miracle response, but is it the right response or have you created a temporary compensation for your client (right before you send them into training or competition) ?  Activation is a 2 way street, there is the input into the brain and a corresponding motor output. If you are just rubbing out some muscles and get a stronger muscle test afterwards, and that is as far as your thoughts go before you turn your athlete loose, then you are a liability in the system. Are you part of the problem or part of the solution ?

Here are 2 paragraphs from this brilliant article. This is worth your time. As a client adapts to their unresolved, partially resolved (yes, even 95% is unresolved) injury(s) a secondary cascade of neurological changes ensue that often force new cortical remapping.  A remapping that is not as fundamentally safe or as sound as the pre-injury mapping yet one that is necessary for protecting further or other injuries. Yet, because it is not the original pristine pattern, it is also one that can begin undercurrents to corrupt other patterns of stability, mobility and movement in cortical and subcortical mappings. Understanding cortical excitability is important, and it can work for you and your client or against you both. It can be used for good or evil.  

If after you read these 2 paragraphs taken from the Alan Needle article in LER (link) you think you might be part of the problem or realize that you are not the magician you think you are, then good, you are on the track to self enlightenment and actually helping people.  Go read Alan’s article and breathe deep, ready to absorb and start yourself into understanding that you are really fixing the brain and not always the muscle, and that means you are gonna have to learn about the brain and how it works and more so how it can deceive you and your client and your training, treatments or therapy.

Come join us on The Gait Guys podcast 58 later this week as we delve into this topic deeper and more broadly.

Shawn and Ivo

PS: nice article Dr. Needle. Thank you !

http://lowerextremityreview.com/article/the-brain-a-new-frontier-in-ankle-instability-research

“Recently Wikstrom and Brown proposed a hypothetical cascade of events that would affect an individual’s ability to “cope” following an ankle sprain and provide a rationale for the varying contributors to instability. For an individual starting from a point of normal function, a lateral ankle sprain will trigger a consistent pattern of changes to the joint from the inflammatory process. Swelling will increase pressure on the joint’s mechanoreceptors, and pain will contribute to inhibition of the reflexes to the joint (arthrogenic inhibition). Together, this means patients will have difficulty sensing the joint and subsequently stabilizing it while excessive mechanical laxity will increase this loss of stability.19

Inflammatory changes may be similar across all patients; however, as symptoms remain and the patient adapts after his or her injury, a secondary cascade of neurological changes may occur that may include cortical remapping. In some patients, these adaptations may be beneficial and serve to protect the joint from further injury. Other patients may maladapt, as sensorimotor reorganization changes the nervous system’s perception of the joint. Variable amounts of laxity, proprioception, and cortical excitability exist throughout populations of healthy, previously injured, and functionally unstable joints. Where these populations diverge may be related to how each is scaled relative to the others. For instance, a joint with greater amounts of laxity may have higher proprioception and excitability to aid in stabilizing the joint, but following injury, these factors may become decoupled, leading to errors in movement and coordination.19”  -Alan Needle, PhD

 

More on EVA foam, impact loading behaviors, and adding shoe inserts.

A few weeks ago we wrote about some thoughts on the maximalist shoe foam trend and how it is possible that more foam could mean alterations in impact loading behaviors that could lead to problems (note we used the word could, and not will).  If there are pre-existing proprioceptive deficits in a limb these issues most likely will rise to the surface. 

The EVA foam in shoes is primarily used to absorb forces via air flow through interconnected air cells in the EVA during shoe deformation under body-weight. When the shoe has seen a finite number of compressive cycles the air cells collapse and the EVA can compact on itself leaving the shoe with an negatively impacting area of compression to fall into.  Shock absorption may be impacted and possibly lead to injury.

The Robbins study we discussed a few weeks ago (link) suggested that the reduction of impact moderating behaviour is 

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.This is presumably an attempt to achieve equilibrium by obtaining a stable, rigid support base through compression of sole materials. Humans reduce impact-moderating behavior, thereby amplifying impact, when they are convinced that they are well protected by the footwear they are wearing. 

These were important points but we wanted to bring to your awareness of the component of the shoe you may have not thought of to this point, the foam foot bed that comes with the shoe, or ones you might add to the shoe  yourself post-purchase. With what we have just taught you in our last blog post and this blog post, we will let you make the connection we are suggesting you be aware of when it come to more foam, changes in foam as the shoes and inserts degrade and impaired impact loading behaviors.

There are just 3 brief study summaries here, take the time to read them and read between the lines now that we have educated you a little better in how to think about them.

Shawn and Ivo

J Appl Biomech. 2007 May;23(2):119-27.

Effects of insoles and additional shock absorption foam on the cushioning properties of sport shoes.

The purpose of this study was to investigate the effects of insoles and additional shock absorption foam on the cushioning properties of various sport shoes with an impact testing method. 

The results of this study seemed to show that the insole or additional shock absorption foam could perform its shock absorption effect well for the shoes with limited midsole cushioning. 

Further, our findings showed that insoles absorbed more, even up to 24-32% of impact energy under low impact energy. 

It seemed to indicate that insoles play a more important role in cushioning properties of sport shoes under a low impact energy condition.

_______

Biomed Mater Eng. 2006;16(5):289-99.

Role of EVA viscoelastic properties in the protective performance of a sport shoe: computational studies.

 Using lumped system and finite element models, we studied heel pad stresses and strains during heel-strike in running, considering the viscoelastic constitutive behavior of both the heel pad and EVA midsole. In particular, we simulated wear cases of the EVA, manifested in the modeling by reduced foam thickness, increased elastic stiffness, and shorter stress relaxation with respect to new shoe conditions. Simulations showed that heel pad stresses and strains were sensitive to viscous damping of the EVAWear of the EVA consistently increased heel pad stresses, and reduced EVA thickness was the most influential factor, e.g., for a 50% reduction in thickness, peak heel pad stress increased by 19%. We conclude that modeling of the heel-shoe interaction should consider the viscoelastic properties of the tissue and shoe components, and the age of the studied shoe.

________________

J Biomech. 2004 Sep;37(9):1379-86.

Heel-shoe interactions and the durability of EVA foam running-shoe midsoles.

A finite element analysis (FEA) was made of the stress distribution in the heelpad and a running shoe midsole, using heelpad properties deduced from published force-deflection data, and measured foam properties. The heelpad has a lower initial shear modulus than the foam (100 vs. 1050 kPa), but a higher bulk modulus. The heelpad is more non-linear, with a higher Ogden strain energy function exponent than the foam (30 vs. 4). Measurements of plantar pressure distribution in running shoes confirmed the FEA. The peak plantar pressure increased on average by 100% after 500 km run. Scanning electron microscopy shows that structural damage (wrinkling of faces and some holes) occurred in the foam after 750 km run. Fatigue of the foamreduces heelstrike cushioning, and is a possible cause of running injuries.

 

More on EVA foam, impact loading behaviors, and adding shoe inserts.

A few weeks ago we wrote about some thoughts on the maximalist shoe foam trend and how it is possible that more foam could mean alterations in impact loading behaviors that could lead to problems (note we used the word could, and not will).  If there are pre-existing proprioceptive deficits in a limb these issues most likely will rise to the surface. 

The EVA foam in shoes is primarily used to absorb forces via air flow through interconnected air cells in the EVA during shoe deformation under body-weight. When the shoe has seen a finite number of compressive cycles the air cells collapse and the EVA can compact on itself leaving the shoe with an negatively impacting area of compression to fall into.  Shock absorption may be impacted and possibly lead to injury.

The Robbins study we discussed a few weeks ago (link) suggested that the reduction of impact moderating behaviour is 

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.This is presumably an attempt to achieve equilibrium by obtaining a stable, rigid support base through compression of sole materials. Humans reduce impact-moderating behavior, thereby amplifying impact, when they are convinced that they are well protected by the footwear they are wearing. 

These were important points but we wanted to bring to your awareness of the component of the shoe you may have not thought of to this point, the foam foot bed that comes with the shoe, or ones you might add to the shoe  yourself post-purchase. With what we have just taught you in our last blog post and this blog post, we will let you make the connection we are suggesting you be aware of when it come to more foam, changes in foam as the shoes and inserts degrade and impaired impact loading behaviors.

There are just 3 brief study summaries here, take the time to read them and read between the lines now that we have educated you a little better in how to think about them.

Shawn and Ivo

J Appl Biomech. 2007 May;23(2):119-27.

Effects of insoles and additional shock absorption foam on the cushioning properties of sport shoes.

The purpose of this study was to investigate the effects of insoles and additional shock absorption foam on the cushioning properties of various sport shoes with an impact testing method. 

The results of this study seemed to show that the insole or additional shock absorption foam could perform its shock absorption effect well for the shoes with limited midsole cushioning. 

Further, our findings showed that insoles absorbed more, even up to 24-32% of impact energy under low impact energy. 

It seemed to indicate that insoles play a more important role in cushioning properties of sport shoes under a low impact energy condition.

_______

Biomed Mater Eng. 2006;16(5):289-99.

Role of EVA viscoelastic properties in the protective performance of a sport shoe: computational studies.

 Using lumped system and finite element models, we studied heel pad stresses and strains during heel-strike in running, considering the viscoelastic constitutive behavior of both the heel pad and EVA midsole. In particular, we simulated wear cases of the EVA, manifested in the modeling by reduced foam thickness, increased elastic stiffness, and shorter stress relaxation with respect to new shoe conditions. Simulations showed that heel pad stresses and strains were sensitive to viscous damping of the EVAWear of the EVA consistently increased heel pad stresses, and reduced EVA thickness was the most influential factor, e.g., for a 50% reduction in thickness, peak heel pad stress increased by 19%. We conclude that modeling of the heel-shoe interaction should consider the viscoelastic properties of the tissue and shoe components, and the age of the studied shoe.

________________

J Biomech. 2004 Sep;37(9):1379-86.

Heel-shoe interactions and the durability of EVA foam running-shoe midsoles.

A finite element analysis (FEA) was made of the stress distribution in the heelpad and a running shoe midsole, using heelpad properties deduced from published force-deflection data, and measured foam properties. The heelpad has a lower initial shear modulus than the foam (100 vs. 1050 kPa), but a higher bulk modulus. The heelpad is more non-linear, with a higher Ogden strain energy function exponent than the foam (30 vs. 4). Measurements of plantar pressure distribution in running shoes confirmed the FEA. The peak plantar pressure increased on average by 100% after 500 km run. Scanning electron microscopy shows that structural damage (wrinkling of faces and some holes) occurred in the foam after 750 km run. Fatigue of the foamreduces heelstrike cushioning, and is a possible cause of running injuries.

 

Remember this kiddo?

We have been following the natural development of this little guy for some time now. For a review, please see here (1 year ago) and here (2 years ago) for our previous posts on him.

In the top 2 shots, the legs are neutral. The 3rd and 4th shots are full internal rotation of the left and right hips respectively. The last 2 shots are full external rotation of the hips.

Well, what do you think now?

We remember that this child has external tibial torsion and pes planus. As seen in the supine photo, when the knees face forward, the feet have an increased progression angle (they turn out). We are born with some degree / or little to none, tibial torsion and the in-toeing of infants is due to the angle of the talar neck (30 degrees) and femoral anteversion (the angle of the neck of the femur and the distal end is 35 degrees).  The lower limbs rotate outward at a rate of approximately 1.5 degrees per year to reach a final angle of 22 degrees….. that is of course if the normal de rotation that a child’s lower limbs go through occurs timely and completely.

He still has a pronounced valgus angle at the the knees (need a review on Q angles? click here). We remember that the Q angle is negative at birth (ie genu varum) progresses to a maximal angulation of 10-15 degrees at about 3.5 years, then settles down to 5-7 degrees by the time they have stopped growing. He is almost 4 and it ihas lessend since the last check to 15 degrees.

His internal rotation of the hips should be about 40 degrees, which it appears to be. External rotation should match; his is a little more limited than internal rotation, L > R. Remember that the femoral neck angle will be reducing at the rate of about 1.5 degrees per year from 35 degrees to about 12 in the adult (ie, they are becoming less anteverted).

At the same time, the tibia is externally rotating (normal tibial version) from 0 to about 22 degrees. He has fairly normal external tibial version on the right and still has some persistent internal tibial version on the left. Picture the hips rotating in and the lower leg rotating out. In this little fellow, his tibia is outpacing the hips. Nothing to worry about, but we do need to keep and eye on it.

What do we tell his folks?

  • He is developing normally and has improved significantly since his original presentation to the office
  • Having the child walk barefoot has been a good thing and has provided some intrinsic strength to the feet
  • He needs to continue to walk barefoot and when not, wear shoes with little torsional rigidity, to encourage additional intrinsic strength to the feet
  • He should limit “W” sitting, as this will tend to increase the genu valgus present
  • We gave him 1 leg balancing “games” and encouraged agility activities, like balance beam, hopping, skipping and jumping on each leg individually

We are the Gait Guys, promoting gait and foot literacy, each and every post.

Podcast 57: The Brain, Ankle Instability, Heel Striking

A. Link to our server:

Direct Download: 

http://traffic.libsyn.com/thegaitguys/pod_5777final.mp3

Permalink: 

http://thegaitguys.libsyn.com/podcast-57-the-brain-ankle-instability-heel-striking

B. iTunes link:

https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138

C. Gait Guys online /download store (National Shoe Fit Certification and more !) :

http://store.payloadz.com/results/results.aspx?m=80204

D. other web based Gait Guys lectures:

www.onlinece.com   type in Dr. Waerlop or Dr. Allen,  ”Biomechanics”

________________________________________

* Today’s show notes:

Neuroscience

Focus on BDNF: Brain Derived Neurotrophic Factor and Gait

http://www.ncbi.nlm.nih.gov/pubmed/10868966

Diabetes. 2000 Mar;49(3):436-44.
Brain-derived neurotrophic factor regulates glucose metabolism by modulating energy balance in diabetic mice.

http://ep.physoc.org/content/94/12/1153.full

Experimental Physiology –
Hot Topic Review
Role of exercise-induced brain-derived neurotrophic factor production in the regulation of energy homeostasis in mammals

The Brain: A new frontier in ankle instability Research
http://lowerextremityreview.com/article/the-brain-a-new-frontier-in-ankle-instability-research

Young Girls and Future injury risk.
http://lowerextremityreview.com/news/in-the-moment-sports-medicine/neuromuscular-training-in-young-girls-boosts-skills-may-reduce-future-risks

PRP review:

http://lowerextremityreview.com/news/in-the-moment-sports-medicine/platelet-rich-progress-data-support-prp-use-for-heel-pain

case: gait guys,

so i got orthotics which hurt like crazy (only on my bad foot). these were not the answer for me. i have an appointment with a hip specialist to see if my  … .
phil

DISCLAIMER

elliptical questions: 
Tried searching your blog but did not find anything on ellipticals.

What correct position is needed to use the machine?
I assume one that would take you out of the anterior pelvic tilt?
By doing this, would that enable  … . 
Q  🙂

Alternative office furniture to avoid sitting at a desk all day
http://www.latimes.com/health/la-he-healthy-workplace-desks-20140222,0,5603953.story

Heel Landing Beats Midfoot In Half-Marathon Study
http://www.runnersworld.com/running-tips/heel-landing-beats-midfoot-in-half-marathon-study