And now, some light reading for a Saturday….

Review of knee proprioception and the relation to extremity function after an anterior cruciate ligament rupture.

J Orthop Sports Phys Ther. 2001 Oct;31(10):567-7

http://www.ncbi.nlm.nih.gov/pubmed/11665744

What the Gait Guys say about this article:

Aren’t you glad you have mechanoreceptors?

As we have discussed in other posts, proprioception is subserved by cutaneous receptors in the skin (pacinian corpuscles, Ruffini endings, etc.), joint mechanoreceptors (types I,II,III and IV) and muscle spindles (nuclear bag and nuclear chain fibers) . It is both conscious and unconscious and travels in two  main pathways in the nervous system.

Conscious proprioception (awareness of where a joint or body part is in space or action) arises from the peripheral mechanoreceptors in the skin and joints and travels in the dorsal column system (an ascending spinal cord information highway) to ultimately end in the thalamus of the brain, where the information is relayed to the cerebral cortex.

Unconscious proprioception arises from joint mechanoreceptors and muscle spindles and travels in the spino-cerebellar pathways to end in the midline vermis and flocculonodular lobes of the cerebellum.

Conscious proprioceptive information is relayed to other areas of the cortex and the cerebellum. Unconscious proprioceptive information is relayed from the cerebellum to the red nucleus to the thalamus and back to the cortex, to get integrated with the conscious proprioceptive information. This information is then sent down the spinal cord to effect a response in the periphery. As you can see, there is a constant feed back loop between the proprioceptors, the cerebellum and the cerebral cortex. This is what allow us to be balanced and coordinated in our movements and actions.

The ACL is blessed with type I, II and IV mechanoreceptors (Knee Surgery, Sports Traumatology, Arthroscopy Volume 9, Number 6)   We remember that type I mechanoreceptors exist in the periphery of a joint capsule (or in this case, the periphery of the ACL) and are largely tonic in function (ie: they fire all the time) and type II are located deeper in the joint (or deeper in the ACL) and are largely phasic (ie they fire with movement). Type IV mechanoreceptors are largely pain receptors and anyone who has injured his knee can tell you all about them.

The article does a great job reviewing the importance of proprioception and how it relates to knee function and concludes “A higher physiological sensitivity to detecting a passive joint motion closer to full extension has been found both experimentally and clinically, which may protect the joint due to the close proximity to the limit of joint motion. Proprioception has been found to have a relation to subjective knee function, and patients with symptomatic ACL deficiency seem to have larger deficits than asymptomatic individuals.”  Bottom line, never quit on the rehab and training of an ACL deficient knee until the absolute best outcome has unequivocally been achieved with certainty that no further improvement can be achieved…… absolute certainty.  Too many stop shy of certainty, and your brain will know it.  And it will show it in small gait, running and athletic skills.

Yup, this is some heavy stuff, but hey…you’re reading it, right?  If we didn’t explain it in detail you might not believe that WE are The Gait Guys ……. more than just foot and shoe guys. After all, there is a brain attached to the other end calling the shots.

Sorting it out so you don’t have to…We remain…The Gait Guys

Ah yes, the Ia and type II afferents.

One of our favorites! Acting as a sentinel from the muscle spindle, concentrated in the antigravity and extensor musculature, Ia and type II afferents live in the belly of the muscle and send information regarding length and rate of change of length to the CNS via the spino cerebellar and inferior olivary pathways. In more simpler terms, think of muscle spindles as small computer chips embedded in the muscle and using la and type II afferents the team act as volume controls helping to set the tone of the muscle and it responsiveness to stretch. If they are active, they make a muscle more sensitive to stretch.

So what does that mean? Muscle spindles turn up the volume or sensitivity of the muscles response to stretch. Remember when we stretch a muscle, it’s response is to contract. Think about when a doctor tests your reflexes. What makes them more or less reactive? You guessed it, the muscle spindle; which is a reflection of what is going on in the higher centers of the brain. The muscle spindles level of excitation is based on the sum total of all information acting on the gamma motor neuron (ie the neuron going to the muscle spindle) in the spinal cord. That includes all the afferent (ie. sensory) information coming in (things like pain can make it more or less active) as well as information descending from higher centers (like the brain, brainstem and cerebellum) which will again influence it at the spinal cord level.

So we found this cool study that looks at spindles and supports their actions:

_____________________________________________________________________

http://www.ncbi.nlm.nih.gov/pubmed/19451207

J Physiol. 2009 Jul 1;587(Pt 13):3375-82. Epub 2009 May 18.

Mechanical and neural stretch responses of the human soleus muscle at different walking speeds.

Cronin NJ, Ishikawa M, Grey MJ, af Klint R, Komi PV, Avela J, Sinkjaer T, Voigt M.

At increased speeds of walking, the muscles themselves (particularly the soleus in this study) become stiffer due to changes in spindle responsiveness. The decline in amplitude and velocity of stretch of the soleus muscle fasicles with increasing walking speeds was NOT accompanied by a change in muscle spindle amplitude, as was hypothesized.

Clinically, this means that the spindles were STILL RESPONSIVE to stretch, even though the characteristics of the muscle changed with greater speeds of action. This may be one of the reasons you may injure yourself when moving or running quickly; the muscle becomes stiffer and the spindle action remains constant (the volume is UP).

Thankfully, we have another system that can intervene (sometimes) when the system is overloaded, and take the stress of the muscle. This is due to the golgi tendon organ; but that is a post for another day…

Geeking out and exploring the subtleties of the neurology as it relates to the system, we remain…The Gait Guys

You have heard of minimalist shoes?

Be scared. Be very scared! Brought to you by our friends at Zero-drop.com:

Maximalist Shoes!

Yikes…what will they think of next?

Your favorite shoe geeks….Shawn and Ivo

Shod vs. Unshod : What the Lieberman-Harvard study really said.

Shod vs. Unshod : What the Lieberman-Harvard study really said.

Thanks to OwenAnderson of  Educatedrunner.com for this excellent article.

http://educatedrunner.com/Blog/tabid/633/articleType/ArticleView/articleId/797/BAREFOOT-RUNNING-WHAT-THE-HARVARD-STUDY-REALLY-SAID.aspx

If you are paying attention to everything that is going on, you want to read this well thought out article.  The Gait Guys are digesting this article and we will render our thoughts and opinions shortly.  But, differing points of view, when laid out logically and with sound reason, deserve consideration. This is how the truth is eventually discovered.

Give this article a productive and attentive read.  We will get back to you shortly.

Summary statement seems to be this….. (quoted word from word from the article).

_____________________________________________________

“Ironically, the popular press has been using the Harvard study as a launching pad for the idea that barefoot running is healthier than shod ambling, even though Lieberman’s paper provided no data at all to test the idea that barefoot running lowers the risk of running injuries!

  Here’s what Lieberman et al actually found:  

(A) Habitually shod runners (groups 1 and 5 from above) who grew up wearing shoes are usually rear-foot strikers (RFS), meaning that their heels make the first impacts with the ground during running, right at the beginning of the stance phase of gait. This is not new information. The strong link between running in shoes and heel-striking has been known for many years.  

(B) Runners who grew up running barefooted or who switched to running barefooted (groups 2, 3, and 4) are generally fore-foot strikers (FFS), meaning that they tend to land initially on the balls of their feet while running, after which their heels drop down to make contact with the ground. Again, this is nothing new – the tight connection between barefoot running and FFS (and also MFS, mid-foot striking) has been general knowledge for years.  

© Impact forces transmitted through the foot, ankle, and leg immediately after impact with the ground are about three times greater in shod runners using RFS, compared with barefoot runners with FFS. Some – but not all - previous studies have shown this same relationship, with RFS producing greater impact force during the first portion of stance, compared with MFS and FFS. The sudden rise in force with RFS, immediately after ground contact, is known as the “impact transient.” The disparity in impact transient between barefoot and shod running represents a “foundation” for the belief that barefoot running is “safer” and less injury producing. While this appears to be logical thinking, it is important to know that no study has ever shown that greater impact forces during the first portion of stance magnify the risk of running injury.  

(D) Rates of loading of impact force are actually quite similar between shod RFS runners and barefoot FFS athletes (Figure 2b from the Nature paper). The rate at which impact force is loaded into the leg has also been suggested to be a risk factor for injury, although convincing proof of this notion does not exist.  

(E) During the early stance phase of barefoot FFS running, there is greater knee flexion, greater dorsi-flexion at the ankle, and a 74-percent-greater drop in the center of mass, compared with shod RFS running. “Vertical compliance” is defined as the drop in the runner’s center of mass relative to the vertical force during the impact period of stance, and it is obviously greater in barefoot FFS running, compared with shod RFS. Vertical compliance varies as a function of running-surface hardness, and this is why force-loading rates are similar for barefoot FFS runners over a wide array of running surfaces (the runners adjust compliance according to surface). This is not novel information, however.  

(F) During barefoot FFS ambling, the ground reaction force torques the foot around the ankle (and therefore increases the amount of work carried out by the ankle, compared with shod RFS running). With shod RFS running, the ankle converts little impact energy into rotational energy. Potentially, this could spike the rate of ankle-area injuries (for example in the Achilles tendon and calf) for barefoot runners, although this hypothesis has not been tested.  

And that was pretty much it! The Nature investigation did disclose some interesting information about the effective mass of the foot and shank (which we won’t discuss here), but it offered no other information about the potential links between barefoot running and either injury or performance.   And that’s why it’s too early for you to consider changing from shod to barefoot running, unless such a shift would be a lot of fun for you. 

There’s just no proof that barefoot running will reduce your risk of injury or make you faster.   In fact, it’s important to remember that most injuries in running are caused by an imbalance between the strain and micro-damage experienced by a muscle or connective tissue during training and the tissue’s ability to recover from such stress. This imbalance can occur when training is conducted shod – or barefooted! A weak or overly tight hamstring muscle which has been undone by excessive mileage won’t care if its owner was running barefooted or wearing shoes – it will still feel the pain. ” -

Owen Andersson, http://educatedrunner.com/Blog/tabid/633/articleType/ArticleView/articleId/797/BAREFOOT-RUNNING-WHAT-THE-HARVARD-STUDY-REALLY-SAID.aspx

In this weeks Neuromechanics weekly, Dr Waerlop takes us from the cortex to the muscle spindle. The journey through the neuraxis continues….

So, the question you need to ask is why they cut the leg off and transplanted the foot/ankle 180 at the lower femur.

If you think about it, it is because he needed a joint to flex like his old knee.  If they put the foot on forward there would be no knee bend (ie. his knee would have only bent as much  as you can point your foot…….the motion of ankle plantarflexion.  This would have been extremely insufficient in range to move as well as this fella is moving. )

By doing a rotation transplasty and putting the foot on backwards he could take advantage of the large range of ankle dorsiflexion.  They talk about the toes alot in this video but this really has nothing to do with the success of this surgery, functionally anyways. The genius of this surgery was using the ankle as a knee hinge. 

Pretty amazing stuff.  Enjoy the brain-twister in understanding how he is using ankle dorsiflexion to replicate knee flexion.  !!!!

taking Gait to another dimension……… Shawn and Ivo

Here Dr. Allen of The Gait Guys introduces some of the initial information necessary to understand proper shoe fit. Topics include body anatomy, shoe anatomy, physiology, biomechanics and compensation patterns. This was part of a private industry lecture where The Gait Guys were asked to help improve the understanding of the concepts critical to better shoe industry choices.

Ivo and Shawn …. what we do while you are sleeping.

our version of crop circles !

watch for signs of our presence at your local beach or wheat field near you !

you are not alone…….

photo from . http://nakedonsharppointystuff.blogspot.com/

So. How did you do?

As you can see, this individual lists to the R upon weight bearing on that side (midstance); did you pick up the increased progression angle of the foot on that side? How about the mild genu valgus?

Why would someone walk like this? There are a few plausible explanations.

1. he has a weak gluteus medius on the R side.

2. he has a R short leg and needs to lean to that side to get the long leg side (L) to clear.

3. impaired left ankle rocker (causing premature heel rise and left side early departure) could also cause him to accelerate onto the right as well.

His options to compensate are to either lean to the weak side ® or to shift his pelvis to the weak side ®. He could also circumduct the leg or flex the thigh to get that side to clear the ground. He has a mild BL circumdcution, probably to clear the knee from the opposite one.

His increased arm swing on the L is to help propel him forward, most likely due to weakness of the external obliques to assist in initiation of flexion of the thigh, and weakness of the gluteus medius, which also helps to propel the leg forward. He also does not push off adequately with the R leg; This is probably due to loss of hip extension and inadequate ankle rocker on that side.

The increased progression angle on the R helps to stabilize his body weight because he is leaning the torso to the R and his center of gravity moves right as well (he makes a wider base for himself)

Yup, you’re a geek!   We remain The Geeks of Gait…Ivo and Shawn

oh look, it appears (but a little hard to tell) ……but it appears we have a casualty !

here is what her ankle is saying …..

“oh no, we do not have enough ankle dorsiflexion to be on this bad boy…….so, who wants to take it guys…….. how about you hyperpronate Mr. Arch, and to help we will drive Mr. Knee medially."  ?

better have enough ankle dorsiflexion if you are gonna play with this monster !

How are your eyes?

Test yourself on this video.

Why does this individual lean to the right during stance phase and have an increased arm swing on the L?

Details Manana!

Welcome to Friday.

Ummm… What can we say? Make sure you watch to the end for the “Grand Finale”. She gets and “A” for effort though we can’t say she passed the gait exam…

The Gait Guys

Part 3: The Problematic Cross-over gait motor pattern. The final piece.

Here Dr. Shawn Allen of The Gait Guys summarizes this gait problem in running form. The Cross-over gait is a product of gluteus medius and abdominal weakness and leaves the runner with much frontal plane hip movement, very little separation of the knees and a “cross over” of the feet, rendering a near “tight rope” running appearance where the feet seem to land on a straight line path. In Part 3, Dr. Allen will discuss a more detailed specific method to fix this. You will see this problem in well over 50% of runners. This problem leads to injury at the hip, knee and foot levels quite frequently. To date we have not met anyone who had a good grasp on this clinical issue or a remedy quite like ours. Help us make this video go viral so we can help more runners with this problem. Forward it to your coaches, your friends, everyone.
Thanks for watching our video

Here Dr. Shawn Allen of The Gait Guys further discusses this gait problem in running form. The Cross-over gait is a product of gluteus medius and abdominal weakness and leaves the runner with much frontal plane hip movement, very little separation of the knees and a “cross over” of the feet, rendering a near “tight rope” running appearance where the feet seem to land on a straight line path. In Part 2, Dr. Allen will discuss a more detailed specific method to fix this. You will see this problem in well over 50% of runners. This problem leads to injury at the hip, knee and foot levels quite frequently. To date we have not met anyone who had a good grasp on this clinical issue or a remedy quite like ours. Help us make this video go viral so we can help more runners with this problem. Forward it to your coaches, your friends, everyone.
Thanks for watching our video

-Shawn and Ivo……The Gait Guys

Funny Nancy Sinatra clip on Zero-drop.com→

Thanks to our friend, Bill Katovsy on  http://zero-drop.com for sharing a classic Nancy Sinatra clip from the The Ed Sullivan Show

Video presentation: The Problematic Cross-Over Gait pattern. Part 1

Here Dr. Shawn Allen of The Gait Guys works with elite athlete Jack Driggs to reduce a power leak in his running form. The Cross-over gait is a product of gluteus medius and abdominal weakness and leaves the runner with much frontal plane hip movement, very little separation of the knees and a “cross over” of the feet, rendering a near “tight rope” running appearance where the feet seem to land on a straight line path. In Part 2, Dr. Allen will discuss a more detailed specific method to fix this. You will see this problem in well over 50% of runners. This problem leads to injury at the hip, knee and foot levels quite frequently. To date we have not met anyone who had a good grasp on this clinical issue or a remedy quite like ours. Help us make this video go viral so we can help more runners with this problem. Forward it to your coaches, your friends, everyone.
Thanks for watching our video, thanks for your time.
-Dr. Shawn Allen, The Gait Guys

Welcome to Neuromechanics Weeekly. This week Dr Waerlop discusses the afferent sensory pathways and brings us from the receptor to the higher centers. Hold on tight!

The Truth About Treadmills: A Neurological Perspective

Gender differences in walking and running on level and inclined surfaces. 

Chumanov ES, Wall-Scheffler C, Heiderscheit BC. Clin Biomech (Bristol, Avon). 2008 Dec;23(10):1260-8. Epub 2008 Sep 6.

What the Gait Guys have to say about this article:

This article highlights some of the differences in gait between males and females on treadmills. Though treadmills don’t necessarily represent real life, they are an approximation. While reading this article, please keep the following in mind:

1. the treadmill pulls the hip into extension and places a pull on the anterior hip musculature, especially the hip flexors including the rectus femoris, iliopsoas and iliacus. This causes a slow stretch of the muscle, activating the muscle spindles (Ia afferents) and causing a mm contraction (ie the stretch reflex). This acts to inhibit the posterior compartment of hip extensors (especially the glute max) through reciprocal inhibition, making it difficult to fire them.

 2. Because the deck is moving, the knee is brought into extension, with stretch of the hamstrings, the quads become reciprocally inhibited (same mechanism above).

 3. The moving deck also has a tendency to put the ankle in dorsiflexion, initiating a stretch reflex in the tricep surae (gastroc/soleus) facilitating toe off through here and pushing you through the gait cycle, rather than pulling you through (with your hip extensors).

 4. the moving deck forces you to flex the thigh forward for the next footstrike (ie footstance), firing the RF, IP and Iliacus, and reciprocally inhibit the g max

If your core isn’t engaged, the pull of the rectus femoris and iliopsoas/iliacus pulls the ilia and pelvis into extension (ie increases the lordosis) and you reciprocally inhibit the erectors and increase reliance on the multifidus and rotatores, which have short lever arms and are supposed to be more proprioceptive in function. Can you say back pain?

In summary, treadmills are not the scourge of humanity, but do have some pitfalls for training, and equal amounts of “backwards” running should be employed (with great caution, mind you)

With that being said, lets look at the results: increased hip internal rotation and adduction, as well as more glute activity for the ladies. Not surprising considering women generally have a larger Q angle (17 +/- 3 degrees for females, 14 +/-3 degrees for males) and greater amounts of hip anteversion (average 14 degrees in females vs 8 in males). The larger Q angle places more stress at the medial knee (compression of the medial femoral condyle and usually increased pronation as the center of gravity over the foot is moved medially) and thus more control needed to slow pronation (from the glutes to control/augment internal rotation). Greater hip anteversion means the angle of the femoral head is greater than 12 degrees to the shaft of the femur. This moves the lower extremity into a more internally rotated position, approximating the origin and insertion of the adductors, making them easier to access. With an increased Q angle and easier access, greater demands are placed on adductors in single leg stance (which is considerably greater in running), This increased adductory moment places more demand on the gluteus medius (and contralateral QL) as well, to stabilize the pelvis and this correlates with speed and incline, also found in the study.

The take home message? Don’t throw away your treadmill! The treadmill can be an excellent diagnostic tool! Gluteal and adductor insufficiencies will be more visible (and probably more prevalent) in females, especially those running or walking on treadmills. The hip extension and ankle dorsiflexion moment created by a treadmill works against some of the stabilizing mechanisms (glute inhibition, ankle dorsiflexor inhibition) and help to highlight some of the subtle gait abnormailities you may miss otherwise.

Abstract from Article

BACKGROUND: Gender differences in kinematics during running have been speculated to be a contributing factor to the lower extremity injury rate disparity between men and women. Specifically, increased non-sagittal motion of the pelvis and hip has been implicated; however it is not known if this difference exists under a variety of locomotion conditions. The purpose of this study was to characterize gender differences in gait kinematics and muscle activities as a function of speed and surface incline and to determine if lower extremity anthropometrics contribute to these differences.

METHODS: Whole body kinematics of 34 healthy volunteers were recorded along with electromyography of muscles on the right lower limb while each subject walked at 1.2, 1.5, and 1.8m/s and ran at 1.8, 2.7, and 3.6m/s with surface inclinations of 0%, 10%, and 15% grade. Joint angles and muscle activities were compared between genders across each speed-incline condition. Pelvis and lower extremity segment lengths were also measured and compared.

FINDINGS: Females displayed greater peak hip internal rotation and adduction, as well as gluteus maximus activity for all conditions. Significant interactions (speed-gender, incline-gender) were present for the gluteus medius and vastus lateralis. Hip adduction during walking was moderately correlated to the ratio of bi-trochanteric width to leg length.

INTERPRETATION: Our findings indicate females display greater non-sagittal motion. Future studies are needed to better define the relationship of these differences to injury risk.

PMID: 18774631 [PubMed - indexed for MEDLINE]

Yup, we’re gait nerds….Don’t laugh….You are too if you are reading this…..

The Gait Guys: finding other uses for treadmills, other than for hanging the laundry…..

DVD's we have made, for sale.

Here is a list of what we currently have available on DVD:

Item Name:

The Performance Core

Item #:

Performance I

Price/ea:

$39.95

• The Neuro Core: Abdominal neurological connection and control

• Purpose of the DVD in Core Training

• The Problems with Crunches and Sit Ups

• Bracing and Hollowing:

• Breathing and the Core

• Exercise: Bicycles- Right and Wrong

• Problems with Leg Lifts

• Exercise: The Non-Tripod Core Exercise for Oblique Activation

• Core Progression Order: …. Pathologic motor pattern compensations

• Exercise: Tripod with a Ball

• Exercise: the Abdominal “Chairs”

• Exercise: “Chairs” progressions continued…….. getting harder !

• Exercise: The Glute and Core Combine

• Exercise: The Hip Extension Pattern- Assessment and Progression

• Exercise: Hip Extension progressions continued…….getting harder

• Exercise: Bridges and Planks. The Right and Wrong and progressions

•  Exercise: Motor Pattern Setting……The Sit to Stand Core

Item Name:

The Performance Squat

Item #:

Performance III

Price/ea:

$39.95

The Performance Squat – First phase development exercises and concepts

DVD Running time: 46 minutes

• The Reason for the Squat: Problems

• Where the Squat Begins: The Foot Tripod Concept

• The 3 Rockers of Movement in Gait and the Squat

• How the Foot Works: The Basics of what you need to know right now

• Another Look at the Foot: Foot types and Shoe Types

• The Foot and Pelvis Position: Its Impact on Movements and Squats

• Video Case Study of a Sprinter: Issues of Foot and Limb Positions

• A Brief (Very Brief) Discussion on Shoes and their issues with the Squat

• Exercise: The Texas Walk- A skill for early squat preparation and performance

• Exercise: The Potty Squat- The proper motor sequence

• Exercise: The Ball Squat- With Breathing concepts intertwined (critical neuro training)

• Exercise: The Hip Hike

• Exercise: Iso (Isometric) Drops Done Right (“Box Drops and Depth Drops”)

•  Video Case Study: Drop Assessment frame-by-frame stop motion analysis

Item Name:

The Performance Theories

Item #:

Performance II

Price/ea:

$39.95

  The Performance concepts: Dialogues on Training Concepts

DVD running time: 65 mintues

• What is the definition of the core and what does it entail ?

• Physiologic overflow of muscles with respect to joint motion

• Isotonic Exercise concepts

• Physiologic characteristics of muscle types

• Strength Training: Neural Adaptation

• Motor Pattern Muscle Compensation Concepts

• Exercise Prescription Concepts

• Hip Extension Motor Pattern: A discussion on compensations

• Neurologic Reciprocal Inhibition: Principles of joint movement and stability

• The Concept of Tight and Short Muscles: They are different

• Stretching: Good or Bad

Item Name:

Performance Series: Advanced Core

Item #:

Performance Series: Advanced Core

Price/ea:

$39.95

This DVD will take viewers into the next step of the Core. Doctor Allen and Doctor Waerlop will cover the always favorite exercise the sit-up. They will show the many ways athletes misuse the exercise and show a perfect sit-up. They will also demonstrate and explain other exercise to take athletes to the next level with their core development, including proper technique for lat pulls

Item Name:

Performance Series. Advanced Squat

Item #:

Advanced squat

Price/ea:

$39.95

This DVD will take viewers into the next step of the squat: the traditional squat. Doctor Allen and Doctor Waerlop will cover the perfect technique needed to develop the glutes instead of the quads in “the king of all exercises”. They will also cover fixing some errors as well as the lunge. Every body part from the foot to head placement will be covered.

Item Name:

Power block- Glute development

Item #:

Power block- Glute development

Price/ea:

$29.95

This DVD was filmed in Chris Korfist’s garage on a nice Sunday afternoon. Dr. Allen and Chris were developing a better way to do the glute power block and they decided to film their discussion. They discuss proper technique on many exercises which serve the purpose of developing explosive glutes and making sure the foot and glute are connected. Now your glute power can be more than “all show and no go.

Performance Core Trio: $99

Advanced Series Trio: $99

All 6 DVD’s: $179.95

We also have the following download available on Payloadz:

Foot Function and the Effects on the Core and Body Dynamics      http://store.payloadz.com/go/?id=914689

email us at ……   thegaitguys@gmail.com