Gait Cycle Basics: Part 5

Swing Phase

Our final chapter in this series….

Swing phase is less variable in its classification. It begins at toe off and ends at heel strike. It comprises 38% of the gait cycle.There must be adequate dorsiflexion of the ankle, and flexion of the knee and hip to allow forward progression.

The following classification is most commonly used:

Early swing: occurring immediately after toe off. There is contraction of the dorsiflexors of the ankle, and flexors of the knee and hip

Midswing: halfway through the swing cycle, when the swing phase leg is passing the midstance phase extremity. Acceleration of the extremity has occurred up to this point.

Late swing: deceleration of the extremity in preparation for heel strike. There is contraction of the extenders of the thigh and knee, as well as dorsiflexors of the ankle.

Perry defines the phases as:

Initial swing: the 1st third of swing phase, when the foot leaves the round until it is opposite the stance foot.

Mid swing: the time from when the swing foot is opposite the stance foot until the swinging limb is anterior to the stance phase tibia

Terminal swing: from the end of midswing, until heel strike

And there you have it. A nice review of the gait cycle. Probably more than you wanted to know, but we want to give you the facts.

Telling it like it is. We are…The Gait guys

Does calf stretching increase ankle dorsiflexion range of motion? A systematic review.→

Here is a big topic. Everyone seems to think that stretching makes a big difference, truth is it makes a difference, but it is not big. But is “some” enough ?

The topic comes up in a range we really feel is important, ankle dorsiflexion range.  You hear us talk about it all the time as “ankle rocker”.  The facts are that you need 100+ degrees of ankle dorsiflexion range to achieve normal biomechanics across the ankle ankle  in walking, and near 115 degrees for running (put another way, 10degrees past 90degrees vertical for walking and 25degrees past vertical for running, ref. T. Michaud). 

If you do not have these ranges then you must compromise normal biomechanics.  This is where functional pathology starts, ie. injuries.

This study found the following:

The meta-analyses showed that calf muscle stretching increases ankle dorsiflexion after stretching for

< or = 15 minutes (WMD 2.07 degrees; 95% confidence interval 0.86 to 3.27),

> 15-30 minutes (WMD 3.03 degrees; 95% confidence interval 0.31 to 5.75), and

> 30 minutes (WMD 2.49 degrees; 95% confidence interval 0.16 to 4.82).

So, what does this mean ?

Well, upon initial impressions it seems that none of them gained more than 3 degrees of dorsiflexion range, even after 30 minutes of stretching.  The study suggested that these numbers according to research stats, were “statistically significant”.

But in our mind, if you have 90 degrees range, a “statistically significant” loss in our opinion, then gaining another 3 degrees (ok, lets jump the moon and assume you stretched for 60 minutes and achieved 5degrees)…..well, you are still not at 100 degrees and have to compromise normal mechanics which could mean injury.

Bottom line, you have to find another way to get this range back, stretching is not going to float your boat the whole way.  This is why we like the shuffle walks (as seen on our YouTube videos) to engage and strengthen the anterior compartment.  This strength will help to reflexively release the tight posterior compartment.   You cannot have a relatively normal lengthened posterior compartment if the anterior team is insufficiently strong. 

The Gait Guys

Just in Time for Friday! We want to thank Bill at zero-drop.com for reminding us about these great shoes. We like the “mukluk like” design with minimal drop from heel to toe, as well as the simplistic, single density sole. Hope these are available for all those kids who don’t like to lace their shoes….

Gait Cycle Basics: Part 4

Pronation as a shock absorber

Heel strike, a traumatic deceleration event with the transfer of weight from one extremity to the other, creates shock which must be attenuated. This is accomplished by 4 distinct mechanisms:

1. ankle plantar flexion at heelstrike, followed by eccentric contraction of the pretibial muscles to decelerate foot fall.

2. subtalar pronation. As the coefficient of friction between the calcaneus and the ground increases, the talus slides anterior on the calcaneus while plantar flexing, adducting and everting. This motion causes concomitant internal rotation of the lower leg. Both these actions cause a time delay, allowing force to be absorbed over a longer period of time.

3. knee flexion. This is a reaction to the heel rocker, forward motion of the tibia, and passive tension in the posterior compartment. It is slowed by eccentric contraction of the quadriceps

4. contralateral pelvic drop, which is decelerated by the ipsilateral hip abductors (primarily gluteus medius). This occurs as weight is suddenly dropped on the contralateral limb

The rockers and shock attenuation are dependent on the integrity of the joints involved, their associated ligaments and cartilage, the functionality of the musculature crossing them and their neuromuscular integrity along with appropriate cortical control of the actions. Being physical medicine practitioners, we understand that the anatomy and physiology cannot be separated and must consider these different components while evaluating the patient.

The Gait Guys….Yup, we ARE foot nerds….Hey, someone has to do it….

Gait Cycle Basics: Part 3

As Promised: The Rockers…

According to Perry, progression of gait over the supporting foot depends on 3 functional rockers

heel rocker: the heel is the fulcrum as the foot rolls into plantar flexion. The pretibial muscles eccentrically contract to decelerate the foot drop and pull the tibia forward

ankle rocker: the ankle is the fulcrum and the tibia rolls forward due to forward momentum. The soleus eccentrically contracts to decelerate the forward progression of the tibia over the talus. Ankle and forefoot rocker can be compromised by imbalances in strength and length of the gastroc/soleus group and anterior compartment muscles.

forefoot rocker: tibial progression continues and the gastroc/soleus groups contract to decelerate the rate of forward limb movement. This, along with forward momentum, passive tension in the posterior compartment muscles, active contraction of the posterior compartment and windlass effect of the plantar fascia results in heel lift.

Now see if you can pick out the rockers in today’s video.

The Gait Guys… We are everywhere!!

Gait Cycle Basics: Part 2

Gait Cycle components

Let’s begin today with a typical walking gait cycle.

There are 2 phases: stance and swing. It comprises approximately 62% of the gait cycle. Inman and Scranton use the following classification:

Heel strike: when the heel hits the ground

Full forefoot load: weight is transferred anteriorly to the forefoot

Heel lift: when the heel begins lifting off the ground

Toe off: the beginning of propulsion

They further divide this into a contact period (heel strike to full forefoot load), a midstance period (from full forefoot load to heel lift) and a propulsive period (from heel lift through toe off)

Jaqueline Perry, the Matriarch of gait, uses a slightly more descriptive classification which we prefer:

Initial contact: when the foot 1st touches the floor

Loading response: weight bearing on the loaded extremity from initial contact and continues until the opposite foot is lifted for swing

Midstance: the 1st ½ of single limb support, beginning when the opposite foot is lifted until weight is over the forefoot

Terminal stance: begins with heel rise and continues until the opposite foot strikes the ground

Pre swing: when initial contact of the opposite extremity begins and toes off ends

She also describes 3 tasks to be performed during a gait cycle: weight acceptance (the limb is able to bear weight), single limb support (when weight is supported by one limb with the other in swing phase), and swing limb advancement (moving the opposite limb through space to become the next stance phase leg.

The question is, how do we adequately progress over the stance phase leg? Stay tuned to our next post for a primer on the 3 rockers….

The Gait Guys…Promoting gait literacy and understanding for the clinician and the consumer.

This week we will focus on the basics of gait and the gait cycle in our attempt to assist in gait literacy

Gait Cycle Basics: Part 1

Steps and strides….

What does the gait cycle that have to do with therapy or rehabilitation? Well, most people walk at some point in the day, and most have walked into your office. If people can’t carry the changes you made on the table and incorporate it into walking, then what you do will have limited effectiveness. Thus, the need for understanding the gait cycle as it relates to rehabilitation or how it can give you clues to the biomechanical faults present. An example is a loss of functional hip extension and chronic LBP/ SI dysfunction. This could be due to a myriad of reasons, from weak glutes, loss of ankle dorsiflexion, or even a dysfunctional shoulder. Understanding how these seemingly unrelated body parts integrate into the kinetic chain, especially while moving upright through the gravitational plane.

One gait cycle consists of the events from heel strike to heel strike on one side. A step length is the distance traveled from one heel strike to the next (on the opposite side). Comparing right to left step lengths can give the evaluator insight into the symmetry of the gait.  Differences in step length, on the simplest level, should cause the individual to deviate consistently from a straight line (technically it should cause the individual to eventually walk in a large circle!).  Often, compensations occur functionally in the lower kinetic chain to compensate for the differences in step length to ensure that you walk in a straight line.  It is these longstanding complex compensations that are the generators of many of our patient’s complaints.

A stride length is the distance from heel strike to heel strike on the ipsilateral side (the distance covered in one gait cycle.  Step width, or base of gait, is the lateral distance between the heel centers of two consecutive foot contacts (this typically measures 6-10 cm).  Foot progression angle is the angle of deviation of the long axis of the foot from the line of progression (typically 7-10 degrees). Çhanges in the progression angle can be due to both congenital (torsions, versions) as well as developmental reasons.

Next time we will take a closer look at the gait cycle itself. Yup, we are still…The Gait Guys

special thanks to Dr. Tom Michaud, who has allowed us to use these images in our book

The pedograph as a window to the gait cycle

Have you ever studied footprints on the beach or looked at the print left by a wet foot when you get out of the water? These are some of the most primitive types of pedographs.

The pedograph, 1st described by Harris and Beath in 1947 is a rubber mat surface with multiple protruding, small grid lines on one side, which, when covered with ink, imprints an underlying sheet of paper when weight (usually a foot) passes over it. Relative plantar pressures are indicated by the size and density of the inked area, creating a “footprint” reflecting passages of force through the foot at that instance in time.  They have fallen into and out of usage over the years, often discarded for more expensive technology such as pedobarographs, individual pressure sensors, and pressure sensitive mats, which have computer interfaces and can provide many useful measurements and calculations to assist the clinician with rendering a diagnosis. These systems, though more precise in some ways (provided a controlled, reproducible testing procedure) are often thousands of dollars, require a computer and the necessary skills, and have a substantial learning curve. 

The pedograph in contrast is simplistic, inexpensive, and reliable and only requires that the user have an intact visual pathway and cerebral cortex and knowledge of the events occurring in the gait cycle. With some practice and a good knowledge base, the subtle nuances detected by the sensitive pedograph (nuances that can be undetected with high end computer driven plantar pressure devices) can offer information critical to a precise diagnosis and give solid clues to gait flaws and compensations.  With minimal training using a pedograph, reproducible “prints” can be produced for analysis, in light of your findings clinically. They also make wonderful educational tools for your patients and clients!

An essential part of a comprehensive patient evaluation should include examination of the entire kinetic chain both in a static and dynamic fashion. Often what you see statically is either directly translated to or compensated for in the dynamic evaluation. (It is important to note that many of the available foot scan units available from orthotic companies scan a patient in a static standing position and give little information on how the feet and lower limb dynamically engage the ground during movement.) The pedograph is a useful visual tool representing a 2 dimensional image of tridimensional motion, and you are seeing the end product and compensation (or lack thereof) of the individuals mechanics at that point in time. Because of the specificity of what you are seeing refers to a particular point in time, technique and reproducibility are of paramount importance. Prints should be performed several times to insure what you are looking at is what you are looking at, and not movement artifact, because of the way the patient stepped on to or off of the mat.

With a pedograph, seeing is believing. When you have objective data about how an individual moves through space and how their joints and motor system help them to accomplish that, you have a better appreciation for the type or form of therapy which may be most appropriate. In the hands of a skilled clinician, seeing abnormal plantar pressures tells you where the biomechanical fault lies, and thus where manipulation may be appropriate, which muscles need strengthening and where neuromotor coordination is lacking and gait rehabilitation is needed.  

excerpted from the 1st edition of our Book “Pedographs and Gait Analysis: Clinical Pearls and Case Studies” Trafford Publishing

How do I know if my orthotic is working?

Foot orthotics are easy, no? You get casted, it gets built, you put it in your shoe and you’re good to go, right? Wrong!

Orthotics or “Orthotic Therapy” as we call it is an ongoing process. If an orthotic is doing it’s job, your foot should change (for the better) and your prescription should become less. and less….Until you no longer need them… At least in an ideal world.

Remember, orthotics are designed to help you adapt to your environment better. Unlike a footbed, they should change the biomechanical function of your foot. A lot should go into getting fit for an orthotic, otherwise they can actually cause some of the problems they are purported to fix!

First of all, there should be a history of you and whatever is going on, with an inventory of all your past injuries. Sometimes there is a pattern that can be recognized and gives your provider clues as to what may be going on with you.

Next you should have a thorough examination of your lower kinetic chain, including the feet, ankles, knees, hips and low back. This should include range of motion, muscle strength, muscle recruitment patterns and joint function, along with reflexes, sensation and balance or proprioception. This gives us a benchmark and defines weaknesses and strengths.

Now there should be an analysis of your gait, preferably with stop motion video which allows us to slow down movements and assess subtle abnormalities that may not be visible during normal speeds of movement. If you are there for cycling orthotics, then a video of your stroke pattern is made. Sometimes, footage of your skiing technique can be helpful as well.

At this point, it should be obvious to both you and your orthotic provider whether or not an orthotic is needed. If so, a non weight bearing cast in terminal stance phase (This is a specific position of your ankle and foot) should be performed. This is usually followed by the prescription of appropriate stretches and exercises, specific to your condition. Shoe recommendations should also be given, since different foot types require different footwear characteristics. This will be good news for the ladies who like many shoes. Most guys just want the pain to stop and won’t care what they look like, as long as they are not pink!

Now you have an idea of what goes into (or should go into) building the perfect orthotic for you. Ask lots of questions of whoever is building them for you and make sure they are answered to your satisfaction. They should be a stepping stone to your recovery and  not a crutch for you to depend on. 

Telling it like it is, we are… The Gait Guys

We have been trying to classify some of these gaits and are looking for a government grant to do so….. We figure they may have a short leg or two….

The Gait Guys at the Movies: Terminator 2→

The Gait Guys at the Movies: Terminator 2.  Here is a spot we did for Natural Running Centers………fun stuff, good data. We hope to offer a more technical version soon, with more details but for now……..Enjoy

Vintage Shawn and Ivo. One of our early PODcasts on forefoot varus. Enjoy our banter on this commonly seen pathology!

Is it possible to take 3 minutes off your half marathon ?

An article by Michael Warburton, published as an Internet post on barefoot theory, seemed to spark some of the resurgence of the method of running.  In his brilliant 2001 piece he had some interesting thoughts and pointed out some noteworthy facts.  He indicated that research showed that an extra mass of 100 grams attached to the foot diminished the economy of running by one percent.  Thus, two 10-ounce shoes (the weight of a lightweight training shoe) could have a compounding crippling effect on efficiency by more than five percent.  In tangible terms, that could be more than six additional minutes for a world-class marathoner, taking a world record to a mere first-group finish. 

link  to Warburton article:  http://www.sportsci.org/jour/0103/mw.htm

Pronation Primer: Part 2

The problem with OVERPRONATION

The consequence of under or over pronation ultimately means other articulations, including the spine, will have to attenuate more shock. Over time, this may lead to articular cartilage degeneration, disc degeneration, or ligamentous laxity, due to repetitive stresses.

What about assymetrical pronation?

It is rare that people over or under pronate the same amount on each side. Excess midfoot pronation on the right causes more internal rotation at the right knee (see above picture), and an increased valgus stress here. This puts the quadriceps at a mechanical disadvantage and stretches the adductor group, often making them stretch weak, and shortens the abductors, especially the gluteus medius, which often becomes short weak. The right foot, since it is now a poor lever, will often be externally rotated and toes claw, because the center of gravity has moved medially and they are trying to make that limb stable to bear weight on so they can progress forward. They will often toe off from the inside of the great toe (as is often evidenced by a pinch callus here). The medial rotation of the lower leg causes internal rotation of the thigh and anterior nutation of the pelvis on that side, both which now put the gluteus maximus at a mechanical disadvantage, limiting hip extension on that side. Now the extension has to occur to somewhere, so it often occurs in the lumbar spine, along with rotation and lateral bending to that side, increasing compression on the right facets. Now the vestibular system kicks in to right the head and we get contraction of the left paraspinals. Arm swing usually increases on the contralateral side to assist in propulsion forward. What effect do you think THAT has for about 10 thousand steps a day on spinal mechanics? What effect are we having on the nervous system and what neuroplastic changes are occurring? Hmmmm….

Having both feet planted on solid ground, or rather having both feet planted solidly on the ground should concern you. As you can see, knowing about pronation and its effects on the entire kinetic chain is paramount to the clinician. The effects reach far beyond the foot and can often be the root of recurrent biomechanical faults in the human frame.

And some people thought it was as easy as slipping an orthotic in there…

Yup, we still are….The Gait Guys

Pronation Primer: Part 1

A lot of folks seem to be on a mission to eliminate pronation, calling it the scourge of humanity and source of human ailment. While we agree that overpronation causes biomechanical faults in the lower kinetic chain, so does under pronation, and some pronation is necessary and required for normal locomotion. We hope this post serves to clarify any misconceptions there may be about it.

When most people think of pronation, they think of midfoot pronation, or pronation about the subtalar or transverse tarsal joints. Pronation can actually occur about any articulation or bone, but with respect to the foot, we like to think of rearfoot (ie. talo-calcaneal), midfoot (talo-navicular) and forefoot (transverse tarsal). The question is why does this matter?

Pronation, with respect to the foot, is defined as a combination of eversion, abduction and dorsiflexion  (see picture attached) which results in flattening of the planter vault encompassing the medial and lateral longitudinal arches. In a normal gait cycle, this begins at initial contact (heel strike) and terminates at midstance, lasting no more than 25% of the gait cycle.

In a perfect biomechanical world, shortly following initial contact with the ground, the calcaneus should evert 4-8 degrees, largely because the body of the calcaneus is lateral to the longitudinal axis of the tibia. This results in plantar flexion, adduction and eversion of the talus on the calcaneus, as it slides anteriorly. At this point, there should be dorsiflexion of the transverse tarsal (calcaneo-cuboid and talo-navicular joints). Due to the tight fit of the ankle mortise and its unique shape, the tibial rotates internally (medially). This translates up the kinetic chain and causes internal rotation of the femur, which causes subsequent nutation of the pelvis and extension of the lumbar spine. (Hmm, this is beginning to sound like a common cause of low back pain) This should occur in the lower kinetic chain through the 1^st half of stance phase. The sequence should reverse after the midpoint of midstance, causing supination and creating a rigid lever for forward propulsion.

Pronation, along with knee and hip flexion, allow for shock absorption during throughout the 1^st half of stance phase. Pronation allows for the calcaneo-cuboid and talo-navicular joint axes to be parallel making the foot into a mobile adaptor so it can contour to irregular surfaces, like our hunter gatherer forefathers used to walk on before we paved the planet. Problems arise when the foot either under pronates (7 degrees valgus results in internal tibial rotation), resulting in poor shock absorption or over pronates (> 8 degrees or remains in pronation for greater than  50% of stance phase).

Wow, kind of overwhelming, eh? Stay tuned for part 2 tomorrow.

We remain….The Gait Guys…Telling it like it is…..

Advanced Gait and Running Topics: Biomechanics, Details of Foot types, Multiple Case Studies→

another course offering is now available for your viewing.

The course by The Gait Guys, Biomechanics 203: Advanced Gait and Running Topics: Biomechanics, Details of Foot types, Multiple Case Studies.  3 hour lecture, segemented.  This is one of our long awaited courses.  Tons of detailed materials in this course.  (available for 3 hours continuing education).

Whether  you are looking for continuing education credits, or just looking to learn more about true foot function and how it integrates with the rest of the body…….this is a great lecture.

• More discussion on the walking and running gait cycles
• Apply the biomechanics of the pelvis and lower kinetic chain during walking to clinical practice
• Predict and discuss problems and clinical strategies that can arise from altered lower extremity biomechanics
• Apply visual analysis skills
• Evaluate case studies in gait analysis
• Clinically apply solutions for gait abnormalities
• video case studies mingled into each topic

Click the link above, when you get to the website, choose CONTINUING EDUCATION COURSES, and from the pull down menu select CHIROPRACTIC DOCTOR.  Look under BIOMECHANCS, select course 203.

Enjoy

The Gait Guys, Biomechanics 202: Foot Function and the Effects on the Core and Body Dynamics→

Now available for your viewing.

The course by The Gait Guys, Biomechanics 202: Foot Function and the Effects on the Core and Body Dynamics

Whether  you are looking for continuing education credits, or just looking to learn more about true foot function and how it integrates with the rest of the body…….this is a great little lecture.

• Describe how the motor and sensory homunculus relate to the foot and are integral to training and rehabilitation
• Discuss the 3 rockers of the foot
• Give examples of problems that result from a loss of the 3 rockers of the foot
• Explain the concept of pelvis neutrality and its effect on training
• Describe and examine the tripod of the foot
• Breakdown most movement into 2 basic rules or tenets
• Give examples of the problems which can arise if the 2 basic rules or tenets of movement are not followed
• Discuss the clinical consequences of loss of the medial and lateral tripods of the foot

Click the link above, when you get to the website, choose CONTINUING EDUCATION COURSES, and from the pull down menu select CHIROPRACTIC DOCTOR.  Look under BIOMECHANCS, select course 204.

Enjoy

The Tarahumara and Masai    Part 3

From our PODcast archives (This is the 4th PODcast we did several, actually, many years ago !) a discussion of barefoot and the MBT from our early beginnings as The Homunculus Group. This is vintage Shawn and Ivo……

Enjoy!

The Gait Guys: Proper Shoe Selection and Foot Types.→

Now available for your viewing.

The course by The Gait Guys, Biomechanics 204:

• Describe and identify how the parts of a running shoe affect running biomechanics
• Compare and contrast different shoe constructions to the biomechanical needs of an individual
• Determine the appropriate last shape for different foot types
• Discuss the biomechanical consequences of improper vs. proper selection of last types
• Predict which features in a shoe are necessary to correct faulty gait patterns

Whether  you are looking for continuing education credits, or just looking to learn more about shoes and proper shoe type, etc…….this is a great little lecture.

Click the link above, when you get to the website, choose CONTINUING EDUCATION COURSES, and from the pull down menu select CHIROPRACTIC DOCTOR.  Look under BIOMECHANCS, select course 204.

Enjoy

Gum Shoe…. def.

Noun….gumshoe

1. a sneaker or rubber overshoe

2. (slang) A detective or private eye

But in this case……. it quite literally looks like a shoe with gum stuck to the heel and ground ! This pair of pumps is gonna get looks. Pretty amazing what some people think of. Probably courtesy of the guy in the cubical beside you who’s supposed to be doing your mothers taxes but instead is photo-shopping stuff like this to serve his shoe fetish. None the less……a creative mind. We cannot remember where we found this pic……. we would love to give credit to the innovator if he or she is out there…..drop us a line !

By the words of the legendary Rock band Boston………Walk on…..

“Take a look around and tell me what you can see
I guess that all depend on exactly what you want it to be
Is your cup half-full? Is your cup half-empty?

How can you get what you need in the land of plenty?
Everybody gets carried away
Everybody’s trying everyday to remind you
Leave it behind you
What’s it take to see?
What’s it take to believe right from wrong?
Never knowing where you belong
Walk On
Walk On ”