Cannabis users walk differently.

We all have experienced or viewed the alcohol impaired gait at some point in our lives, the sloppy malcoordinated limb and torso movements. There are some classic observable characteristics there that many of us are familiar with.  But what about cannabis gait ?

"The research from the University of South Australia, published in the journal Drug and Alcohol Dependence, found those who smoke cannabis tend to move their shoulders less and elbows more as they walk. The pilot study also found marijuana users swing their knees more quickly during walking. The differences in gait were small and found in people who smoked a light or moderate amount of cannabis. Some changes were so small it was impossible for a specialist to detect."

However, the thing we found interesting was the papers final question, as to whether the subtle gait changes over a longer period of time would increase or become more apparent.

Not insinuating that Mystic Mac is a user, but he sure does help us hit our "reduced antiphasic gait" home with a glorious demo !

*We have seen this variation in arm swing gait many times before. We have discussed numerous times that when there is a reduction in the normal shoulder and pelvic "girdle" counter rotations, the normal antiphasic gait that presents us with the clearly obvious opposite arm-leg swings, we lose the ability to tap into these oscillations that afford us this free arm and leg swing.  So, when these girdle rotations are reduced, the limb movement has to come from further down into the limb, from elbow movement, a sort of casting the lower arm forward from biceps and triceps activity and from a kicking forward of the lower leg from quadriceps activity instead of hip flexion-extension activity.

We have mentioned this reduction in the normal antiphasic gait many times previously in our arm swing articles. Particularly, the reduction in the amplitude of the separation in the shoulder-pelvic girdle oscillations in those with spine pain. The more the spine is "twisted and wrung out" by these opposite swings, the more spinal motor unit compression, which can increase spine pain. Just search our blog for "arm swing" (30+ articles on the topic there). Thus the question remains , why does cannabis cause this same reduction?

Gait affects everything, and everything seems to affect our gait.

http://www.9news.com.au/national/2017/09/01/15/25/marijuana-users-walk-differently-australian-study-claims

Calf strength, the medial foot tripod, and pain in the great toe

It has become evident that this component, the proper function of the 1st ray complex, is overlooked in some of the clinical world. Hallux joint pain is a difficult one to diagnose and treat at times. The source of pain and dysfunction can seemingly come from anywhere, but the more one understands the complex mechanics of this joint and regionally associate joints, the better clinical results one will achieve.  

One thing that has become recurrently obvious upon the many outside professional referrals that come though my office is the imbalance and/or weakness or endurance impairments in the posterior mechanism in relation to a painful 1st metatarsophalangeal joint (MTP). When I say posterior mechanism I am referring to the gastrocnemius, soleus, peronei, long flexors, and tibialis posterior namely. 

And, let me be clear, putting a theraband under the 1st metatarsal, encouraging your client to drive greater downward purchase of the head of the 1st MET during simulated foot tripod loading, does not necessarily help your client if their 1st MET is slightly more dorsiflexed. Do not be fooled by the flashy rehab guru tricks out there, proper clean function is achieved, not forced. If you have not earned it, you do not own it. 

It is quite simple really. If one does not have balanced function, including skill (motor pattern), endurance or strength of plantarflexion of the ankle, one cannot properly posture the first metatarsal (1st MET) in plantarflexion to sufficiently alter the sesamoid posturing underneath the metatarsal head, to sufficiently engage the unique eccentric axis (and it's necessary shift) of the 1st MTP to enable ample clean hallux dorsiflexion. Furthermore, without all this,  one will not be able to anchor the medial foot tripod properly.  This can lead to pain, functional hallux limitus, hallux rigidus to name a few. And, let me be clear, putting a theraband under the 1st metatarsal, encouraging your client to drive greater purchase of the head of the 1st MET during foot loading, does not necessarily help your client if their 1st MET is slightly more dorsiflexed. Do not be fooled by the flashy rehab guru tricks out there gang, proper clean function is achieved, not forced. 

A simple example might be a runner who fatigues the posterior mechanism in a long run. As the calf fatigues, they lose ample heel rise, thus ample plantarflexion of the 1st MET, thus proper posturing and translation of the sesamoids, thus successful eccentric axis shift, and thus clean dorsiflexion of the 1st MTP joint.  A player in a jumping sport who has less than ample strength of the posterior mechanism can have much the same issue at the resultant toe.  These are just garden variety examples.  But, should be clear that ample skill, endurance and strength (S.E.S.), our favorite mnemonic, of the posterior mechanism is necessary for pain free, functional toe off in the gait cycle or in jumping mechanics. 

If you are not systematically testing for these S.E.S. issues in the posterior mechanism, you are likely missing a major component in the proper posturing of the ankle and foot and thus proper functioning of the first ray complex and thus enabling clean function at the 1st MTP joint.  

(Sidebar rant: My past personal problems at this great toe joint started when a fellow chiropractor pulled on my toe many moons ago, for some random reason. It was the proverbial,  axial distraction "adjustment". The cavitation was heard around the world (the saliva inducing "pop" that fools many into blissful success), and my problems began.  I had painful dysfunction for many years after that for some strange reason, something was damaged but I was too stubborn and stupid to fix my own foot. I eventually remedied the problem through diving deeper into the complex mechanics of this joint and regionally associated areas. For this very intimate reason, it is why I am not one to perform this maneuver or recommend it. If we can be smarter in our understanding, we can be wiser in our interventions. Besides, axial distraction of this joint is not normal function of this joint. If I had a soap box to stand on for this topic, I would tell people to stop doing HVLA manipulations to this joint, mobilizations are more than ample to elicit a joint range response or a neurologic mechanoreceptor response. The more you understand this profoundly complicated and interesting joint, the 1st MTP joint, the more you will understand how to help your client. But, what do I know, I am just a dumb chiropractor, right Joe Rogan :) 

- Shawn Allen, the gait guys

Some Basic Tenets of Gait

Initial contact? Loading response? Mid stance? Terminal Stance? pre swing? Are these terms that are familiar to you? Hmmm. How about the wrong orthotic for someone with internal tibial torsion? Join us in this excerpt from a recent Gait and Needling seminar

https://vimeo.com/226733697

Podcast 108: Calf Muscle Power & Motor Signatures.

Running, gait, human sociomotor interactions and the power of behavioral plasticity.

A. Podcast links:

http://traffic.libsyn.com/thegaitguys/pod_108f.mp3

http://thegaitguys.libsyn.com/podcast-108-motor-signatures-motor-learning-calf-power

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

C. Gait Guys online /download store (National Shoe Fit Certification & more !)
http://store.payloadz.com/results/results.aspx?m=80204

D. other web based Gait Guys lectures:
Monthly lectures at : www.onlinece.com type in Dr. Waerlop or Dr. Allen, ”Biomechanics”

-Our Book: Pedographs and Gait Analysis and Clinical Case Studies
Electronic copies available here:

-Amazon/Kindle:
http://www.amazon.com/Pedographs-Gait-Analysis-Clinical-Studies-ebook/dp/B00AC18M3E

-Barnes and Noble / Nook Reader:
http://www.barnesandnoble.com/w/pedographs-and-gait-analysis-ivo-waerlop-and-shawn-allen/1112754833?ean=9781466953895

https://itunes.apple.com/us/book/pedographs-and-gait-analysis/id554516085?mt=11

-Hardcopy available from our publisher:
http://bookstore.trafford.com/Products/SKU-000155825/Pedographs-and-Gait-Analysis.aspx

________________________

Show Notes:

The way you move gives clues.
http://neurosciencenews.com/movement-personality-traits-3907/

http://rsif.royalsocietypublishing.org/content/13/116/20151093

Biomechanics of Propulsion
http://lermagazine.com/cover_story/biomechanics-of-propulsion-implications-for-afos

Altered plantar pressures
http://link.springer.com/article/10.1007%2Fs00167-016-4015-3

Calf strength screen?  Um, maybe not. Specifics matter.
Thanks to barbellphysio.com for putting this up. We would like to take this deeper, because it is very important.
This screen in our strong opinion is mostly for testing sub optimal endurance, sure there is some strength assessment going on but if you are trying to determine strength, is it single rep strength ? Very likely what he truly meant is how does the calf strength hold up at a 20 rep endurance challenge.  This is more accurate and we are fussing about specifics here, but specifics matter.
*However, the potentially BIG HOLE here in the assessment, is that “perceived” top end calf/heel raise ROM is not necessarily top end FULL ROM. If one side is truly weak, and you cannot get to top end strength (say the heel is 10% lower than the other side) someone has to be there to assess and notice that top end strength failure (a top end ROM that could reduce as endurance challenge continues, but someone has to be there to observe. Going on just “feel” alone is a bad recipe there). One like is not going to feel that top end range loss even if it is large, you will perceive the effort which could feel the same as the good side but actually be a loss.  And is 20 reps enough? Sure, it is a start but is your test really telling you what you think it is telling you ? This is being shown as a gross screen in our opinion but it has holes even as a screen.  Top end strength, something we talk about here often, is critical to performance. Top end loss means  terminal plantarflexion ROM is insufficient, and this can lead to a whole host of injuries and biomechanical flaws including achilles tendonopathy to mention just one. Remember, the gastroc does  not play alone here (and gastrocs crosses the knee joint posteriorly, some of the other posterior compartment muscles do not). There is soleus, peronei, tib posterior, long flexors etc. So are you doing your test with bent knee or locked ? It makes a difference if you are trying to tease things out.  Are you ramming your toes into flexion to get more out of them to make up for a loss elsewhere ? Is the forefoot or rearfoot inverting or everting  on the up or down phase ? These things matter. Specifics matter.  For example, you can see in this video that the hip is a little lateral to the foot placement. This will mean that the heel rise will result in a lateral forefoot weight bearing load. Do you want to see if the peronei are doing their job during the heel rise ? Well then you should go into a hip hike to posture the hip over the foot so that you can get the weight bearing transition to occur terminally over to the big toe, the peronei and lateral gastroc help drive that last little shift and if they are weak and you are not driving that last piece of the movement the test may not show you the whole picture you are thinking it is. Clue, if you cannot feel the lateral compartment contract to finalize that medial foot weight bearing load shift, you may be weak there. You better assess then.

Can you do 20 reps at 80% of the full plantarflexion ROM or can you do 20 reps at 100% full plantarflexion ROM ? There is a performance difference, and to the client unobserved, the 80% on one side may feel and perform like the 100% on the other side. But make no mistake, there is a world of difference.  Someone has to  watch that you are comparing apple to apples, and not apples to figs, oranges, turnips or squash.
-Dr.Shawn Allen, the gait guys

https://www.youtube.com/watch?time_continue=55&v=QdWiXHsI8Q8

The Mighty Interossei

By request of one of our readers (Thank you Richard S), we were asked to “dig up” some information about the interossei. After scouring the literature, we turned up an interesting paper, talking about their anatomy. 

Of interesting note, the paper found extensive connections of the musculature with the surrounding fascia (talk about myofascial meridians!) as well as a fairly consistent slip of the peroneus longus which contributes to the 1st dorsal interossei. This is important considering the peroneus fires from midstance on, as do the interossei (and other foot intrinsics). Perhaps (since as the fore foot is extending in late midstance and pre swing) it assists in descending the head of the 1st metatarsal and resisting extension (contracting eccentrically) of the metatarsal phalangeal joints, helping to maintain stability of the fore foot for push off. 

“The extensive connections among the interossei indicate that they could be important stabilisers of the foot during those times when rigidity is required. The pull of the interossei is transformed across the tarsometatarsal joints by means of their attachment to the ligamentous meshwork. Thus they will act upon the tarsometatarsal joints. Crossing those joints on their plantar aspect, the interossei are well placed to assist in resisting extension. Even though their close attachment proximal to the joints creates a short lever arm and therefore relative inefficiency as flexors when weight is borne on the ball of the foot (MacConaill, 1949), the large mass of the combined interossei probably indicates that they do have a significant role in resisting extension at these joints. Also, the shapes of the tarsometatarsal joint surfaces restrict angular motion.”

Definitely a good read and available FREE full text online here

PAUL J. KALINt AND BRUCE ELLIOT HIRSCH: The origins and function of the interosseous muscles of the foot  J. Anat. (1987), 152, pp. 83-91 

Texting and Walking.  Your gait will change when you are texting on your phone.

You are going to want to put away your cell phone after you read this, or at least hide your parent’s phones. *(the video link attached here has likely been blocked by ABC News, you should see a forwarded link to their youtube feed. If not,

here it is

.  So you think you are a multi-tasker do you ?  Do you know how much cerebral cortex real estate is necessary to walk or drive and text ? Just try texting while walking for 5 seconds in an unfamiliar environment and see what happens.  Dual tasking is difficult especially when one task is cognitive and the other is spacial and motor. At some point something has to give, especially if you are on the edge of tapping out the executive function centers in the brain because of early disease or age related mental decline.  This has never been more prevalent than in the elderly and the number of mounting studies proving that dual attention tasks lead to a dramatic increase in age related fall injuries.  If you look into the literature the fall rate increases from anywhere from 11 to 50%, these are strong numbers correlating falls and dual attention tasking in the elderly.  Certainly the numbers are worse in the frail and gait challenged and fewer in healthier elderly folks, but the correlation seems to be strong particularly when there are even early signs of frontal cortex demise. We have talked about this on several recent podcasts

(check out podcasts 80-85)

and this has been rooted even further from one of our neurology mentors, Dr. Ted Carrick.   Recently in the Journal of Applied Biomechanics, Parr and associated took 30 young able bodied healthy individuals with experience texting on cellular phones. The study used an 11-camera optical motion capture system on a 8m obstacle-free floor. 

The study showed a reduction in gait velocity in addition to significant changes in spatial and temporal parameters, notably, step width, while the double support phase of the gait cycle increased.  Furthermore, and equally disturbing, toe clearance decreased but luckily step length and cadence decreased. 

Thus, it appears that the attention draining texting task generally forced the brain to slow the gait, reduce step length while improving stability via increasing step width and double support phase of gait, keep in mind that these are young healthy experienced individuals with no early cognitive challenges. 

This is not the case in aging adults, or in adults with factors that have either challenged gait stability (degrees of impaired balance, vision, vestibular, proprioception etc) or challenged frontal cortex function where that functionality of the brain is already nearing its tipping point for adequate function.  Sadly, these are all factors in the aging adult and they are why falls are increased and riskier for the elderly. Essentially, what the studies are showing is that dual tasking creates a distraction that can amplify any sensory-motor challenges in the system.  Mind you, there are studies that show that if the dual task is remedial such as talking while walking the effects are more muted, however in those who are at the tipping point capacity of mental executive function, mere talking (cognitive linguistic engagement), can also tip the system into deciding whether to focus on the gait or the talk but not both adequately.  Something will have to give in these folks, safe competent dual tasking is beyond the ability of their system.  As we have eluded to here, there are many factors and variables that can challenge the system. Visual challenges such as low light vision problems or depth perception challenges can act similarly on the system to dual tasking attempts and thus magnify fall risk. What about sensory challenges from a spinal stenosis or peripheral neuropathy such as in advancing diabetes?  Balance and vestibular challenges, let alone factors such as unfamiliar environments (perhaps magnified by vision challenges) as precursors are a foregone conclusion to increase fall risk in anyone let alone the elderly. By this point in this article it should be a given that texting while doing anything else is a dual tasking brain challenge that could lead to a fall, an embarrassing spill into the public pool or into a fountain at the mall let alone driving off a cliff or into a crowd of people.  But are all of these unfortunate people showing signs of frontal cortex/executive function impairment? Perhaps not, especially if they are healthy.  One has to keep in mind that texting is a high demanding cognitive attention task, even though we think nothing of it as a healthy adult. Think about it, one has to engage a separate screen other than the environment they are trying to walk through. Additionally, one has to think about what they are trying to text, engage a seperate motor program to type, then there is spelling, choosing text recipients, sending the message, watching and listening for a response, and the list goes on meanwhile the person is still trying to run the gait subprograms.  We take it for granted but texting is highly engaging and adding walking can tip the system into a challenge or failure if we are in a crowd, unfamiliar environment, low light etc.   So if you have ever wondered why elderly people trip and fall in even the most benign environments, it is likely a compounded result of challenges to situation and spatial awareness and working memory with many possible factor challenges. Again, things like poor lighting, vision limitations, unfamiliar environment, vestibular limitations, numbness in the feet, talking or even if they are simply carrying the afternoon tea to the sun room these things all are dual tasking and some require higher demands from the executive function brain centers.   Any factor(s) which tax the already-reducing executive function centers in the elderly subtract from the most basic elements required for upright posture and gait.  If dual-tasking can impair healthy young individuals, the elderly are a forgone conclusion to have magnified risks.   There can be a plus to all of this however. If the goal were to only reduce falls and fall risks in the elderly, an astute clinician can work this to their favor and do gait challenges and retraining in the office environment while safely stacking dual task challenges to expand and restore some executive function capabilities.  We are never too old to learn and lay down improved motor and cognitive patterns. So, use this information to your advantage to improve function instead of delivering it as a dark cloud to hang over your clients, whether they are elderly or neurologically challenged.  In summary, put down the darn phone, trust us, that text can wait.  Rather, enjoy the sunshine, the smiling faces, the trees.  If you are driving or walking, dump the phone and pay attention to traffic and your environment. Stop and wave to a friend. Teach your kids about this texting problem, they are likely already oblivious to many risks in the world, and this one likely hasn’t crossed their mind either. At the very least, help the elderly lady or man cross the street. By now you should understand all that they are consciously and subconsciously trying to calculate to negotiate the street crossing. Their declining executive function is often a mental feat all on its own, but having to actually add the physical act of walking (which is likely already showing aspects of age related biomechanical decline) might just be their tipping point leading to a fall.  So offer your arm, a warm smile, and think everything of it, because someday it will be you at that street corner with sweaty palms and great fear.  

Dr. Shawn Allen, one of the gait guys

References : 1. 

Eur J Neurol.

 2009 Jul;16(7):786-95. doi: 10.1111/j.1468-1331.2009.02612.x. Epub 2009 Mar 31. Stops walking when talking: a predictor of falls in older adults?

Beauchet O

1, 

Annweiler C

, 

Dubost V

, 

Allali G

, 

Kressig RW

, 

Bridenbaugh S

, 

Berrut G

, 

Assal F

, 

Herrmann FR

. 2. 

J Appl Biomech.

 2014 Dec;30(6):685-8. doi: 10.1123/jab.2014-0017. Epub 2014 Jul 9. Cellular Phone Texting Impairs Gait in Able-bodied Young Adults. 

Parr ND

1, 

Hass CJ

, 

Tillman MD

. 3. 

Gait Posture.

 2014 Aug 20. pii: S0966-6362(14)00671-7. doi: 10.1016/j.gaitpost.2014.08.007. [Epub ahead of print]  Texting and walking: effects of environmental setting and task prioritization on dual task interference in healthy young adults. Plumer, Apple, Dowd, Keith. 4. 

Gait Posture.

 2012 Apr;35(4):688-90. doi: 10.1016/j.gaitpost.2011.12.005. Epub 2012 Jan 5.  Cell Phones change the way we walk.  Lamberg, Muratori 5. 

Int J Speech Lang Pathol.

 2010 Oct;12(5):455-9. doi: 10.3109/17549507.2010.486446.  Talking while walking: Cognitive loading and injurious falls in Parkinson;s disease. 

LaPointe LL

1, 

Stierwalt JA

, 

Maitland CG

.

The Bouncy Gait: Premature heel rise gait. Taking another look.

This is a great video example of a premature heel rise during gait. You should be able to clearly see it on the left foot (and this was toned down after we brought it to his awareness!).  The heel rise occurs early in the stance phase of gait, instead of the late stance phase.

We have talked about this bouncy type vertically oriented gait many times in blog posts and in our podcasts.  This is a pretty prevalent problem in the world, mostly because so many people have impaired ankle rocker/dorsiflexion from weak anterior compartments and short/tight posterior compartments.  None the less, for the majority, this is a pathologic gait pattern and it will impart undue stress into the posterior mechanism (calf-achilles complex). Just think about it, this person is going vertical at or prior to the tibia achieving 90degrees (perpendicular to the ground) instead of continuing to progress the tibia to 110+ degrees to enable normal timely pronation and foot biomechanical events.  This is not a normal gait. Period. This will change the function of the entire posterior chain upward. 

If you want to see another great example  from the frontal plane, check out this cute video representation of a vertial/premature heel rise bouncy gait. 

This gait style is caused by a premature heel rise from joint range limitation and/or from premature engagement of the gastrosoleus (and sometimes even the long toe flexors, you will see them hammering and curled in many folks). It can be a learned habitual pattern and nothing more, we have even seen it even in child-parental gait modeling in our offices. These people will never get to NORMAL full late-midstance of gait (without biomechanical compromise) and thus never achieve full hip extension nor adequate ankle dorsiflexion / ankle rocker. The gait cycle is an orchestrated symphony of timely events and when one or several timely events are omitted or impaired the mechanics are passed into other areas for compensation. This vertical gait style is very inefficient in that the gluteals cannot adequately power into hip extension into a forward progression drive, because the calf is prematurely generating vertical movement through ankle plantarflexion.  This strategy is sometimes deployed because the person actually is significantly ankle dorsiflexion (ankle rocker) deficient.  Meaning, they hit the limitations of dorisflexion and in order to progress forward they first have to go vertical.  This vertical motion, because they are moving into ankle plantarflexion, re-buys more ankle dorsiflexion range which then can be used if they so choose. Obviously, the remedy is to find the functional deficit, remove it and retrain the pattern.  There are a whole host of other problems that go with this compensation pattern but we wanted our mission to stay focused today.  Remember, this is usually a subconscious motor pattern compensation. Is it like the toe walking issue we talked about last week (post link here) ? It is similar in some ways and can have primitive and postural motor pattern implications. We will follow up the “Idiopathy Toe Walking Gait: Part 2” shortly but we wanted to strategically put this blog post ahead of it, because there are similar characteristics and implications. Trust us, there is a method to our madness :)

Shawn and Ivo

The Gait Guys

So you want to do a Gait Analysis: Part 2

This is the second in a multi part series. If you missed part 1, click here.

We have been exploring the gait cycle, one step (literally) at a time. A quick review of the walking gait cycle components:

There are two phases of gait: stance and swing. 

Stance consists of:

• Initial contact
  
• Loading response
• Midstance
• Terminal stance
• Pre-swing

Swing phase:

• initial (early) swing
• mid swing
• terminal (late) swing

today, lets explore Loading Response

we remember that Loading response occurs when there is eight bearing on the loaded extremity from initial contact. This continues until the opposite foot is lifted for swing.

Lets look at what is happening here at the major anatomical areas:

Foot

• Pronation begins: This is when the proverbial “rubber hits the road” occurs. Hopefully the coefficient of friction of the heel with the ground is great enough that pronation of the midfoot begins. As the calcaneus slows, the talus slides anteriorly and plantar flexes, adducts and everts, unlocking the subtalar joint and (hopefully) moving toward making its axis parallel with the calcaneo cuboid joint at midstance (more of that next time).
  

• because of this motion, the calcaneus everts approximately 5°

• both of these motions serve to lower the center of gravity of the leg, deepening the ankle mortise to provide more stability to the ankle

• Both of these motions (especially adduction of the talus) initiate internal rotation of tibia and lower leg

• these actions are attenuated by eccentric action of both the long flexors and extensors of the ankle, as well as the foot intrinsics

Ankle

• The ankle plantar flexes 5-10 °. This motion is attenuated by eccentric action of the anterior compartment muscles of the lower leg
• this serves to absorb shock (remember pronation is a shock absorber? if not, see here)

• Ankle rocker occurs (click here for a review of the rockers of the foot)

Knee

• Flexion to 20°. This is attenuated largely by the quadriceps, contracting eccentrically

Hip

• The hip is at full flexion at loading response and now begins to extend. This is facilitated by a brief contraction of the gluteus maximus (which started at initial contact)

Starting to see what is happening? Can you understand why you need to know what is going on at each phase to be able to identify problems?

We are The Gait Guys. Two geeks spreading the word. WE appreciate your help doing the same.

So you want to do a gait analysis? Part 1

From casual observation to a computer driven model, before you can know what may be wrong with a gait, you need to know what is right. Knowing what is happening at each phase of the gait cycle is essential. This series will explore just that and provide you with an overview of what should be happening.

Let’s begin with a typical walking gait cycle. There are two phases: stance and swing. It comprises approximately 62 percent of the gait cycle.¹ Jaqueline Perry^2,3 uses this descriptive classification to describe stance phase:

• Initial contact: When the foot first 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 first half 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 toe-off ends.

Swing phase is divided into 3 parts

• initial (early) swing: when the extremity is being accelerated just after pre swing; this action initiates supination in the opposite, stance phase leg
• mid swing: largely passive
• terminal (late) swing: when the extremity is being actively decelerated, largely through eccentric action of the muscles

How about we start with initial contact, commonly called “heel strike”.

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 four distinct mechanisms:

• Ankle plantar flexion: At heel strike, followed by eccentric contraction of the pretibial muscles to decelerate foot fall.
• 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.
• 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, with the abdominals acting as a primary anchor.
• Contralateral pelvic drop: This is decelerated by the ipsilateral hip abductors (primarily gluteus medius) and lateral chain, as defined by Myers.⁴ It occurs as weight is suddenly dropped on the contralateral limb.

What is happening biomechanically? Lets look at the major anatomical areas:

•  Foot

the foot should be supinated at this point, as it should be from preswing. It is dorsiflexed, inverted and adducted. 

• Ankle

The ankle should be neutral or slightly dorsiflexed

• Knee

the knee is usually neutral or slightly flexed and the thigh and leg externally rotated approximately 4-6 degrees

• Hip

The heel strike hip should be flexed 20-30° and the lumbar spine neutral; the opposite hip should be extended 20-30° and equal to the amount of flexion present in the initial contact hip.

Today, look for aberrances at initial contact in your clients and patients. Knowing what is normal is the 1st step toward knowing what isn’t. Got it?

Next post in this series (not necessarily our next post) will cover loading response.

Ivo and Shawn

1. Root MC, Orion WP, Weed JH. Normal and Abnormal Function of the Foot. Los Angeles: Clinical Biomechanics, 1977.
2. Perry J. Gait Analysis: Normal and Pathological Function. Thorofare, NJ: Slack 1992.
3. The Pathokinesiology Service and the Physical Therapy Department. Observational Gait Analysis. Rancho Los Amigos National Rehabilitation Center, Downey, CA, 2001.
4. Myers TW. Anatomy Trains: Myofascial Meridians for Manual and Movement Therapists. Elsevier: 2001.

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

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