Changing step width alters lower extremity biomechanics during running.

The Cross over gait. We have been talking about this for years, our theories have been supported by the available research and years of patient care.
Here is another study that goes with our ideas, which gives it deeper clinical relevance.

Changing step width alters lower extremity biomechanics during running. Brindle RA1, Milner CE, Zhang S, Fitzhugh EC. Gait Posture. 2014

"Step width is a spatiotemporal parameter that may influence lower extremity biomechanics at the hip and knee joint. Peak hip adduction and rearfoot eversion angles decreased as step width increased from narrow to wide."
Step width influences lower extremity biomechanics in healthy runners. "When step width increased from narrow to wide, peak values of frontal plane variables decreased.

The Fredericson paper (Hip Abductor weakness in distance runners with iliotibial band syndrome) is also supportive. That paper found that increasing step width reduced the strain on the iliotibial band during running. Greater ITB strain and strain rate were found in the narrower step width condition.

We have said it, and will say it again, because someone will post here, "maybe, but all the pros when you watch then and see photos of them, they all have a very narrow step width, basically qualifying for what you guys call a Cross Over gait. So how can you make such bold statements?"
Our response would be, "every attempt at squeezing out more economy in ones gait, walking that fine line of riskier gait mechanics, is a game of playing ECONOMY vs. LIABILITY. And if you have built enough durability and conditioning into your system that you can nudge right up to that fence of RISK, you can play with those liabilities and squeeze out the economy of your gait (like the pros) with that narrower step width. Just be aware and careful, that when you are losing control, as the runs lengthen, that the LIABILITIES are increasing and thus so is the RISK for injury. Just remember, you are likely not a pro, and have not spend the time building a safe zone of durability on your system to endure narrow step width for 26 miles.

A good runner will train the frontal and rotational planes regularly as they engage in their sagittal sport of running. So that as fatigue sets in and the step width begins to narrow, they have some durability of the lower limb to sustain the risky mechanics of the narrow step width. There is a limit for everyone, when the well goes dry.

COM (center of mass) between the feet (inside step width?)

Center of Mass between the feet . . .

The coordinated movement of the spine and pelvis during running. Preece SJ1, Mason D2, Bramah C3.
Hum Mov Sci. 2016 Feb;45:110-8. doi: 10.1016/j.humov.2015.11.014. Epub 2015 Nov 24.

"There appeared to be an anti-phase relationship in the frontal plane between thorax and pelvic motion (Fig. 1b and h)
during stance. Specifically the thorax was laterally flexed towards the stance limb during early stance AND THEN MOVED
TOWARDS A NEUTRAL position during the latter half of stance, as the pelvis became elevated on the contralateral side. The coordination analysis classified the frontal plane pelvis–thorax motion as either anti-phase or pelvis-only during stance (Fig. 4b). This latter classification resulted from the increased motion of the pelvis compared to the thorax which resulted in a more
vertically aligned coupling vector (Seay et al., 2011b) and therefore a coupling angle which was classified as pelvis-only
motion."

This study supports our well founded beliefs that the COM moves within the confines of the step width, it moves TOWARDS, but not over the foot in the early stance phase, and then moves back towards a neutral position during the latter half of stance. One must fully understand the implications of the antiphasic nature in the planes of motion of the body during running (and walking) to understand what the COM is truly doing, what it is not doing, and what it should not be doing.

This study concluded,
"This is the first study to provide an underlying biomechanical rationale for the coordination pattern between the pelvis
and thorax during running in all three body planes. The data showed an anti-phase relationship between these two segments in the sagittal and frontal planes and we suggest that this in a consequence of the requirement to minimise accelerations of the CoM in the AP and ML directions."

The coordinated movement of the spine and pelvis during running. Preece SJ1, Mason D2, Bramah C3.
Hum Mov Sci. 2016 Feb;45:110-8. doi: 10.1016/j.humov.2015.11.014. Epub 2015 Nov 24.

Step width: Head over foot ?

Step width, "head over foot"?

There has been some decent debate on "head over foot" running biomechanics. We postulate from our years of reading research and studying people's gait (coupled with physical examination, a neuromuscular assessment, not just a visual assumption) that the head should remain within the limits of the step width. This theory falls apart if someone is a crossover gait runner or walker (search our blog for this "cross over gait" idea). IF one is a narrow step width (cross over gait, not a literal cross over of course) then the head must basically be over the foot on each step. But this is a gait with severe limitations and lots of risks and biomechanical problems as we have written about many times, though one can say is has some economical aspects which we have proposed many times.
But, if the head is outside the step width, one is leaning and this resembles a pathologic Trendelenburg gait. Can we definitively then say that when the head is outside the foot contact (beyond the limits of a person's step width) that it is problematic? No, but it is likely pathologic and clearly uneconomical.

So the fence seems to be the head over the foot.
If you are outside that fence even a little, you may be (we strongly believe) on the wrong side of the fence. Look at a CP gait (photo below) for example, point made. So, would you rather be on the other side of the fence? We would, we want to be inside the step width and we are fine going right up against the fence (the head foot) but not over top of it. One cannot just say that the head over the foot is better. What about hip and pelvis stability ? If the hips-pelvis are drifting into the frontal plane, this will put the head over the foot as a default. So does this validate the head over foot theory as good in this client ? No, we see this as a problematic gait all the time, lots of hip and spinal stability issues in these clients. One cannot stand and preach on head over foot alone. We just made the case that in a frontal plane drift pelvis client, this is a compensatory default, but it doesn't make it a good thing, far from it.

For now, we will stay put that, with all other faulty mechanics not present, a more sound head position is to be found between the limits of the step width. Yes, right up to the fence of "head over the foot", but not over top as a sound pattern to play with. Why risk falling over the fence on some steps, Try this, stand on one foot, put your head over the foot. In this position, you had to drift the pelvis laterally into the frontal plane. Now try to effectively engage your glute. Enough said, for now. So why would we promote this as an effective running form? More to come we are certain, but we are open to debate, and to being schooled wrong. If you wish, go into our blog (link below) and read up on the effects of step width on gait, and all of the risks/problems that a narrow step width promotes (ie. head over foot).

https://www.google.com/search?q=the+gait+guys+step+width&ie=utf-8&oe=utf-8&client=firefox-b-1-ab

Pod 136: Part 2: Head over Foot? Where should we put our COM (center of mass)?

This podcast (135) and its soon to launch follow up podcast (136), as the intro explains, comes at the tail end of a series of thought debates between Shawn and Ivo with some folks who have a different view point.  While the debate is unsettled because there is not sufficient research to support one side, we feel the research leans towards our side of things.  However, as the debates went on, it became clear to us that both parties were approaching the debate from a different metric to gauge each party's beliefs.  We outline this in the introduction and then more forward into our dialogue.  We hope you find this a productive thought experiment.

Key words: cross over gait, head over foot, HOF, gait, gait analysis, COM, COP, center of mass, center of pressure, step width, sprinting, symmetry, running injuries

Links to find the podcast:

iTunes page: https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138?mt=2

Direct Download: http://traffic.libsyn.com/thegaitguys/pod_136final.mp3

Permalink URL: http://thegaitguys.libsyn.com/pod-136-part-2-head-over-foot-where-should-we-put-our-com-center-of-mass

Libsyn URL:http://directory.libsyn.com/episode/index/id/6586622

Our Websites:
www.thegaitguys.com

summitchiroandrehab.com doctorallen.co shawnallen.net

Our website is all you need to remember. Everything you want, need and wish for is right there on the site.
Interested in our stuff ? Want to buy some of our lectures or our National Shoe Fit program? Click here (thegaitguys.com or thegaitguys.tumblr.com) and you will come to our websites. In the tabs, you will find tabs for STORE, SEMINARS, BOOK etc. We also lecture every 3rd Wednesday of the month on onlineCE.com. We have an extensive catalogued library of our courses there, you can take them any time for a nominal fee (~$20).

Our podcast is on iTunes and just about every other podcast harbor site, just google "the gait guys podcast", you will find us.

When one foot is shorter, and smaller. Gait thoughts to consider.

This person had a congenital “club foot” at birth also know as congenital talipes equinovarus (CTEV). It is a congenital deformity involving one or both feet. In this case it affected the right foot (the smaller one).
Foot size is often measured with the Brannock device in shoe stores, you know, the weird looking thing with the slider that measures foot length and width. In this case, the right heel:ball ratio, the length from the heel to the first metatarsal head, is shorter. The heel:toe length is also shorter, nothing like stating the obvious ! IF they are shorter then the plantar fascia is shorter, the bones are shorter, the muscles are smaller etc.

So, the maximal height of the arch on the right when the foot is fully supinated is less than that of the left side when also fully supinated (ie. during the second half of the stance phase of gait). Even with maximal strength of the toe extensors which we spoke of yesterday will not sufficiently raise the arch on the right to the degree of the left.

Thus, this client is very likely to have a structural short leg. Certainly you must confirm it but you will likely see it in their gait if you look close enough.
Also, you must remember that the shorter foot will also spend fractionally less time on the ground and will reach toe off quicker than the left. This may also play into a subtle limp.
This client may have a mal-fitting shoe, the right foot will swim a little in a shoe that fits correctly on the left. You may be easily able to remedy all issues with a cork full length sole insert lifting both the heel and forefoot. This can negate the shoe size differential, change the toe off timing and remedy much of the short leg issue. You will know that the right foot at the metatarsal-phalangeal joint bending line will not be flexing where the shoe flexes on that right foot. The Right foot will be trying to bend proximal to the siping line where the shoe is supposed to naturally bend. This will place more stress into that foot. This brings up the rule for shoe fit: never size a persons shoe by pinching the toebox to see if there is ample room, the shoe should be fit to meet the great toe bend point to the flex point of the shoe.
Strength of muscles is directly proportional to the cross sectional area of the muscle. With smaller muscles, this right limb is very likely to be underpowered when compared to the left.
All of these issues can cause a failure of symmetrical hip rotation and pelvic distortion patterning.
Altered arm swing (most likely on the contralateral side) is very likely to accommodate to the smaller weaker right lower limb. Do not be surprised to hear about low back pain or tightness or neck/shoulder issues.
A shorter right leg, due to the issues we have discussed above, will place more impact load into the right hip ( from stepping down into the shorter leg) and more compressive load into the left hip (due to more demand on the left gluteus medius to attempt to lift the shorter leg during the right leg swing phase). This will also challenge the pelvic symmetry and can cause some minor frontal plane lumbar spine architecture changes (structural or functional scoliosis…… if you want to drop such a heavy term on it).

Gait plays deeply into everything. Never underestimate any asymmetry in the body. Some part as to take up the slack or take the hit.

post link:

https://thegaitguys.tumblr.com/post/23230149195/we-could-have-easily-made-this-a-blog-post-about

Pod 135: Part 1: Head over Foot? Where should we put our COM (center of mass)?

Key words: cross over gait, head over foot, HOF, gait, gait analysis, COM, COP, center of mass, center of pressure, step width, sprinting, symmetry, running injuries

This podcast (135) and its soon to launch follow up podcast (136), as the intro explains, comes at the tail end of a series of thought debates between Shawn and Ivo with some folks who have a different view point.  While the debate is unsettled because there is not sufficient research to support one side, we feel the research leans towards our side of things.  However, as the debates went on, it became clear to us that both parties were approaching the debate from a different metric to gauge each party's beliefs.  We outline this in the introduction and then more forward into our dialogue.  We hope you find this a productive thought experiment.
 

Links to find the podcast:

iTunes page: https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138?mt=2

Direct Download: http://traffic.libsyn.com/thegaitguys/pod_135final.mp3

Permalink URL: http://thegaitguys.libsyn.com/pod-135-part-1-head-over-foot-where-should-we-put-our-com-center-of-mass

Libsyn URL: http://directory.libsyn.com/episode/index/id/6309104

Our Websites:
www.thegaitguys.com

summitchiroandrehab.com doctorallen.co shawnallen.net

Our website is all you need to remember. Everything you want, need and wish for is right there on the site.
Interested in our stuff ? Want to buy some of our lectures or our National Shoe Fit program? Click here (thegaitguys.com or thegaitguys.tumblr.com) and you will come to our websites. In the tabs, you will find tabs for STORE, SEMINARS, BOOK etc. We also lecture every 3rd Wednesday of the month on onlineCE.com. We have an extensive catalogued library of our courses there, you can take them any time for a nominal fee (~$20).

Our podcast is on iTunes and just about every other podcast harbor site, just google "the gait guys podcast", you will find us.

How the CNS adapts. Exploratory testing of the ground.

What is happening at the 150 meter mark in a 200m sprint when that glute starts to fatigue ? What is happening at the 12th mile in a half marathon when stabilzation around that knee starts to falter?
In this article below, the authors discuss postural adaptations to unilateral hip muscle fatigue. This study merely looks at the effects during standing, so imagine what happens during locomotion when things start to fatigue.

Anyone who has sprained an ankle or banged up a knee knows what it is like to have an automated limping gait. The CNS is trying to reduce and shorten the loading response (and time) on the affected limb. This scenario goes on for awhile, days, maybe weeks, until it becomes somewhat more automated.
We just saw a client in the office just yesterday who had a subtle limp from a foot fracture 6 months ago. I mentioned it in passing, "isn't it amazing that your CNS can still be generating that limping adaptive gait even after 6 months, even now that the pain is no longer present?" His response, "What ? I am still limping? No I'm not ! Am I? Really?" I showed him the video, he was shocked. Things get automated, the CNS adapts, and it often doesn't know when to let go of an adaptive pattern even when it is no longer warrented. It is amazing to think that the brain often cannot logically process the incoming data and revert back to the sensory-motor program that was engaged pre-injury. Amazingly, perhaps the brain still knows better, perhaps it knows that things might seem fine, but lurking beneath the surface the sensory receptors are still sending soft warning signs that things still are not kosher.
We say something like this often to our clients, "The CNS makes momentary adaptive choices, but it has no way of foreseeing the consequences of an adaptive measure which is necessary in the moment. It makes these choices based on perceived stability, necessary mobility, economy, and pain avoidance, most of the time. But, it has no way of seeing into the future to see whether its choices have ramifications, it just chooses what makes the most sense in that moment." This is one of the reasons why we get so cranky about people who offer training and corrective exercise queues to people without deep thought, examination, and consideration. There can be ramifications down the road, that, in the present, are unseen and unknown. For example, just because you are running faster because you altered or augmented a client's arm swing, doesn't mean that newly trained pattern, that might even have the positive performance outcomes, won't have consequences that need to be walked back in the future. This is one of the premises of our recent arguments with the HOF (Head over Foot) crowd, who explicitly convey they only care about the clock and a client's speed, not about their well being down the road. There is no free lunch, the piper always gets paid, but just because we are not there to see the payment, it doesn't mean the day of reckoning isn't coming. We have been playing this human mechanic game now collectively for about 50 years, we know the payback is real, we see it often, eventually the tab for that free lunch shows up.

In this article below, the authors discuss postural adaptations to unilateral hip muscle fatigue. We are again looking for that Piper, he wants to get paid, so what is the consequence to the fatigue ? This study merely looks at standing, so imagine what happens during locomotion when things start to fatigue.

"The purpose of the present experiment was designed to address this issue by assessing the effect of unilateral muscle fatigue induced on the hip's abductors of the dominant leg on bipedal standing."

"Results of the experimental group showed that unilateral muscle fatigue induced on the hip's abductors of the dominant leg had different effects on the plantar CoP displacements (1) under the non-fatigued and fatigued legs, yielding larger displacements under the non-fatigued leg only, and (2) in the anteroposterior and mediolateral axes, yielding larger displacements along the mediolateral axis only. These observations could not be accounted for by any asymmetrical distribution of the body weight on both legs which were similar for both pre- and post-fatigue conditions. The observed postural responses could be viewed as an adaptive process to cope with an unilateral alteration in the hip neuromuscular function induced by the fatiguing exercise for controlling bipedal stance. The increase in CoP displacements observed under the non-fatigued leg in the fatigue condition could reflect enhanced exploratory "testing of the ground" movements with sensors of the non-fatigued leg's feet, providing supplementary somatosensory inputs to the central nervous system to preserve/facilitate postural control in condition of altered neuromuscular function of the dominant leg's hip abductors induced by the fatiguing exercise." - Vuillerme et at, 2009

We have discussed arm swing many dozens of times over the 9 years of blogging research on the web. You can search our blog for "arm swing" and go down the deep rabbit hole we have dug if you wish to learn how arm swing is not only necessary, but highly adaptive ballasts to help maintain balance and effective and adaptive locomotion. They can be used for improving or changing locomotion of all types. They can be looked at as prime movers or passive followers of the higher order leg swing. They can be coached right and wrong. The have a huge impact on COM (center of mass) and COP (center of pressure). And as a tangential comment of the article above, when the adaptive postural responses of the body are activated from a given fatigue in the body, COM and COP must change and adapt to keep us upright in the gravitational plane. These COM and COP changes are exploratory postural compensations, of which altered arm swing is often one adaptive and assistive measure. In this articles discussions, these compensations provide supplemental somatosensory inputs to the central nervous system to "preserve/facilitate postural control in conditions of altered neuromuscular function" when fatigue sets in somewhere. Bringing this all full circle, changing someone's arm swing, because you do not like how it looks (ie asymmetry, cadence, direction, etc), is foolish. The brain is doing it, because it likely has to do it to help adapt to a problem elsewhere that is altering the brain's perception of a safe COP and COM. Your job is to find out why and correct it, not to teach them a new way, which is very likely a new compensation to their already employed adaptive compensation.
-Shawn Allen, the other gait guy

Postural adaptation to unilateral hip muscle fatigue during human bipedal standing. Vuillerme N1, Sporbert C, Pinsault N. Gait Posture. 2009 Jul;30(1):122-5. doi: 10.1016/j.gaitpost.2009.03.004. Epub 2009 Apr 28.

Sagittal gait change in arthritic hips.

Asymmetries are the norm, whether they are anatomic or functional. This however does not mean that there may, or may not, be present or future consequences to the asymmetries.  It can take time for compensations to develop to accommodate these compensations, and it may take even further time for the body to present (and perhaps not present) consequences to the compensations.

In this study, progressing osteoarthritis in the hip began to eat away as some functional parameters that might otherwise have allowed for more symmetrical step and strike lengths, and one must not forget step width has to be in this discussion as well. 

"The patients walked significantly slower than the controls (p=0.002), revealed significantly reduced joint excursions of the hip (p<0.001) and knee (p=0.011), and a reduced hip flexion moment at midstance and peak hip extension (p<0.001). Differences were primarily manifested during the latter 50% of stance, and were persistent when controlling for velocity." - Eitzen et al.

Thus, to walk a straight line, some adaptive compensations will have to occur in the body to enable a linear progression. This might mean altering hip extension patterns, altering hip rotation relationships within the affected hip and thus of the contralateral hip (which might lead to pelvis distortion patterning), pelvis drift in the frontal plane, pelvis drift in the sagittal plane (APT, PPT), asymmetries in spinal rotation and thus arm swing, to name a few just regionally at the hip-pelvis-spine interval. Adaptations must be made. The question is, does your gait assessment afford you the insight to be addressing the problem, or merely their visible compensation, that is the hard part.  And remember what we always say, you gait analysis is only going to show you what your client is doing, not why they are doing it. Thus, fixing what you see is likely not fixing
"the why".

"Reduced gait velocity, reduced sagittal plane joint excursion, and a reduced hip flexion moment in the late stance phase of gait were found to be evident already in hip osteoarthritis patients with mild to moderate symptoms, not eligible for total hip replacement. " - Eitzen et al.

* Differences were primarily manifested during the latter 50% of stance, and were persistent when controlling for velocity.

https://www.ncbi.nlm.nih.gov/pubmed/23256709

BMC Musculoskelet Disord. 2012 Dec 20;13:258. doi: 10.1186/1471-2474-13-258.
Sagittal plane gait characteristics in hip osteoarthritis patients with mild to moderate symptoms compared to healthy controls: a cross-sectional study.
Eitzen I1, Fernandes L, Nordsletten L, Risberg MA.

Your gait analysis is lying to you more than you think. The more difficult motor program your client is running occurs before the gait analysis even begins.

Even before you client walks back to your treatment room, there are several things that we may not be aware of. Gait initiation is a different and more complex motor program than the simple gait motor program.

Here is a little something we do in our clinics, all the time. When the session room is open for the next client, we greet our client in the lobby. We do not have our staff send them back to the room to change and wait for us. We watch them closely, but without them knowing. How does the client stand up? How do they initiate their gait cycle ? How is their balance? How do they carry their bags, purse, backpack ?
We ask them to head back to the session room to get changed, letting them think we are grabbing a drink of water. And then, in a sneaky manner, we watch them stand, initiate gait, and walk back to the room.
We do this, because, gait initiation is separate motor program. It requires several component parts, a squat, weight shift, double support balance acquisition, COP (center of pressure acquisition), step length precalculations, step width precalculation, foot strike targeting, weight shift again, initial weight transition, and then the gait cycle. And gait initiation is different and asymmetrical in people with pain, we know this for a fact in clients with painful osteoarthritis. These clients develop adaptive posturomotor strategies that shorten the monopodal phase on the affected leg.*
For many gait disorders, these are the component parts that will first show up if there is a problem in the system. Gait initiation is more difficult than gait perpetuation. Besides, how we walk when we do not think we are being watched, when we are carrying our things (purse, phone, bottle of water, backpack, etc) is how we typically walk. Clients will show all the goodies we need to see: the turned out foot, the hiked shoulder, the limps, the staggers, stumbles, speed, step width, and the like. We also get to see how they move in the shoes they live in, the heeled ones, the broken down ones, the work shoes.

So, when your client is having a formal treadmill gait analysis, what are you seeing? Their best behavior, or the truth ? One thing is for sure, you do not see the most important program the precedes their treadmill analysis, namely, how they get out of the chair and up onto the treadmill. This stuff matters.
There are clues everywhere, grab all of them, in as natural a manner as possible.

The Gait Guys

*Arch Phys Med Rehabil. 2000 Feb;81(2):194-200.
Asymmetry of gait initiation in patients with unilateral knee arthritis.
Viton JM1, Timsit M, Mesure S, Massion J, Franceschi JP, Delarque A.

Walking: The brain leads the body by one step.

Researchers have discovered that we most accurately hit targets when we see them 1 to 1.5 steps ahead of where we were. This is more difficult that it seems because we are making a plan, and at the same time we're making that plan, we're making a movement based on the stuff that we saw a second and half in the past.
Below this link, you will find our post on projecting and estimating steps. Much along the same lines but with a great video to set it up.

https://www.axios.com/when-walking-the-brain-leads-the-body-by-one-step-1513304440-3035f0bb-a992-403f-b084-51e4205cda58.html
https://thegaitguys.tumblr.com/post/44642195883/the-funny-problem-with-the-stairs-at-brooklyns

Crossing over, running on the line. The narrow step width, we know you do it.

This one, on archive Friday, is a great follow up to our cross over video case earlier this week. Crossing over gait causes increased lateral foot strike, further than normal heel strike (if you choose or naturally deviate towards that type of strike) and often maintenance of lateral foot loads even into midfoot loading response times. It can, and often does, lead to greater, faster, more abrupt pronation and as we discussed earlier this week, troubles with efficient high gear toe off (medial foot/big toe off). It also requires more frontal plane pelvis and hip stability as we discuss here today on a blog post from 2014. The frontal plane will be challenged for its durability because it is obvious from the photo here, that the hip, knee and foot are not vertically stacked, not even remotely. Do you have enough frontal plane stability to endure the liabilities in this typically more efficient narrow step width style of running ? That is the big question. If your ITB is chronically tight, there is reason. if you run this way and have problems later into your long runs, there is a reason (endurance in even the muscles fade, not just cardiovascularly). Read on . . . https://thegaitguys.tumblr.com/post/86411021079/saucony-line-running-and-crossing-over-we-are
 

Saucony: Line Running and Crossing Over

We are big fans of the Saucony line of shoes. We have recommended them to our novice and serious runners for decades now. Currently one of our favorite shoes for our runners is the Saucony Mirage, a beautiful 4mm ramp shoe with no bells and whistles.  It is as close to a perfect zero drop that  you will find without going zero, in our opinion.  That is not to say there are not other great 4mm shoes out there, the Brooks Cadence and the New balance minimus are other beautiful 4mm’s out there.  The Mirage has never failed a single client of ours.  

This was a photo we screen captured from the Saucony Facebook page (we hope that for the sake of educating all runners and athletes that we can borrow this picture for this blog post, please contact us if you would like us to remove it). It is a good page, you should follow it as well.  This picture shows not only a nice shoe but something that we have been talking about forever.  The cross over; this runner is running in such a line that it could be argued that the feet are crossing the mid line. In this case, is the line queuing the runner to strike the line ? Careful of subconscious queues when you run, lines are like targets for the eyes and brain.  One thing we like to do with our runners is to use the line as training however, a form of behavioral modification.  When you do a track workout, use the line underneath you, but keep the feet on either side of the line so that you learn to create that little bit of limb /hip abduction that helps to facilitate the hip abductor muscles.  This will do several things, (and you can do a search here on our blog for all these things), it will reduce the reflexive tightening of the ITBand (pay attention all you chronic IT band foam rolling addicts !), it will facilitate less frontal plane pelvis sway, optimal stacking of the lower limb joints, cleaner patellofemoral tracking and help to reduce excessive pronation /internal limb spin effects.  

There is really nothing negative about correcting your cross over, IF it truly needs correcting.  That is the key question.  Some people may have anatomic reasons as to why the cross over is their norm, but you have to know  your anatomy, biomechanics and neuromechanics and bring them together into a competent clinical examination to know when the correction will lead to optimal gait and when it will drive suboptimal gait. Just because you see it and think it is bad, does not make it so.  

New to this cross over stuff ? Head over to the search box here on our blog and type in “cross over” or “cross over gait” and you will find dozens of articles and some great videos we have done to help you better grasp it. 

* you will also note that this runner is in an excessive lateral forefoot strike posturing.  This means that excessive and abrupt prontation will have to follow through the mid-forefoot in order to get the medial foot tripod down and engaged.  The question is however, is what you are seeing a product of the steep limb angle from the cross over, or does this runner have a forefoot varus (functional or anatomic, rigid or flexible)?  Are the peronei muscles weak, making pre-contact foot/ankle eversion less than optimal ? This is an important point, and your clinical examination will define that right away … . . if you know what these things are.  And if you don’t ? Well, you have found the right blog, one with a SEARCH box. Type in “forefoot varus”, if you want to open up the rabbit hole and climb down it … . . we dare ya ! :-)

Step width, length and gait economy.

We have talked about step with hundreds of times it seems. We get asked all the time about optimal or proper step width in our runners, especially the ones that have a tendency to drop into the higher risk category of "cross over" gait. We like to refer them to our standard reply, "many good things happen with increasing your step width, but there is no need to go beyond the hip distance width, no wider than the hips. You should find more gluteal activation there. However, this is less economical than a narrower step width. But, the narrower the step width, you are juggling the increased economy with increased liability (for injury) and riskier biomechanics. One must earn their way into the higher economy narrow step width with gaining durability in these potentially riskier narrow step with mechanics. Failure to do so is a choice taken at your own risk." This article suggest costly risks to a narrow step width as well.

From the Shorter Abstract

"Humans tend to walk economically, with preferred step width and length corresponding to an energetic optimum. In the case of step width, it is costlier to walk with either wider or narrower steps than normally preferred. Wider steps require more mechanical work to redirect the body's motion laterally with each step, but the cost for narrower steps remains unexplained. Here we show that narrow steps are costly because they require the swing leg to be circumducted around the stance leg. And, we could not agree more. There is definitely a sweet spot for every runner, finding it, and earning the durability required to fend off injury is where the magic lies. RAther than tell your runners where to place their feet , thus you defining their step width, give your clients the appropriate hip and frontal plane stability work to find their low risk sweet spot. After all, most of the foot posturing placement is dictated from the hip and pelvis mechanics, as we have written about extensively previously.

Gait Posture. 2017 Mar 23;54:265-270. doi: 10.1016/j.gaitpost.2017.03.021.

The high cost of swing leg circumduction during human walking.

Shorter KA1, Wu AR2, Kuo AD3.

https://www.ncbi.nlm.nih.gov/pubmed/28371740

Medieval "Turn Shoes": How we used to walk.

In the 1500's in Western Europe, shoes were different. People wore “turn shoes”, leather shoes that were made inside out then reversed for wear. This was likely the beginning of the use of molds to make shoes, carpenters up until the twentieth century would carve a wooden foot model of various sizes to model the process and standardize it.

These "Turn Shoes" were replaced by shoes with a frame construction as shoes changed to adapt to different environments, as streets changed.

The Turn shoes were basically a slip on or lace up thick leather sock. Thus, they were zero drop, soft, and provided much "feel" for the ground. Proprioception was obviously well appreciated.

We have spoken about the difference between heel strike and heel contact in walking. One can safely heel strike if barefoot on soft grass, but one cannot on the hard concrete or asphalt that we have covered much of our world with. Thus, if one were to wear "turn shoes" in our modern era, one would be forced to adapt to a heel contact or "heel kiss" on the ground, meaning, a more predominant forefoot loading style as described in this video.

What he describes, is largely not a choice, it was because they were in soft thin leather sock all day long, and even on wood or hard dirt packed floors and cart paths all day long, the heels would want some reprieve from heel "strike".

Another way around this, to reduce heel strike, is to do it more naturally, by shortening the step and stride lengths a little, by keeping the body mass over the foot strike. "Chi Running" and "Chi walking" are based off of this principle. By moving the body mass forward with the foot, one has to naturally reduce heel strike. If one lags the body mass behind the foot however, the foot moves out in front, and heel strike begins to naturally (or shall we say, unnaturally) out in front, more heavily. This is not exactly desirable, for many reason.  Yet, since most of our shoes have some form of heel lift (a heel to forefoot drop), particular dress shoes (yes, even men's dress shoes, see photo), and even many modern day running shoes, the heel is essentially made more prominent (the heel rise essentially makes the brain think our heel (calcaneus) that much longer. This makes it easier, yet undesirable, to heel "strike" first. Oh what we have done for fashion !

He gets a few things wrong in the video, in terms of "ease" of walking, but largely it is decently done. One has to be careful if they perch the foot out in front like he does in the slower demonstration, in a plantarflexed ankle and foot, one can easily begin to lock up the knees. We often see this in teenagers in flip-flops.

-Shawn and Ivo, the gait guys

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Fatiguing your way to your injury? Endurance Injuries, Part 2

Yesterday we wrote about the importance of endurance acquisition in preventing injuries. It is not a coincidence that many injuries sneak up on athletes in the later part of a game or event. Fatigue can predispose us to the variables that sent up compensation and injury, not always of course, but often.  

We felt it would be worthy work to look into a few other journal articles to make our case, not that it truly needed to be hammered out further, but we like to hammer.

We discovered that novice runner's (1) trunk inclination increased and ankle eversion increased with fatigue. Furthermore, as fatigue increased, it was noted to be prominent in the hip external rotators and hip abductors (2). We have discussed this ad nauseam over the years. Failure in these areas impact one's ability to hold sufficient limb rotation to ensure clean sagittal knee mechanics.  Challenges in these motions also lead to faults in foot targeting.  When these abductors and external rotators fatigue or weaken, hip adduction can often occur leading to undesirable medial foot targeting, hence narrow step width and our favorite soap box topic, the cross over gait. These issues become pronounced at the end of the run according to the Dierks study. However, in the 2nd Dierks (3) study these findings were challenged, "uninjured runners normally experience small alterations in kinematics when running with typical levels of exertion". Similarly, in the García-Pinillos study, (5) no major form failures were noted in endurance athletes that pushed their limits in another type of failure test, the HIIT (high intensity interval) workout. Dierks (3) remarked that "It remains unknown how higher levels of exertion influence kinematics with joint timing and the association with running injuries, or how populations with running injuries respond to typical levels of exertion.". 

None the less, these are just two studies, and there are others to refute it. We do however, challenge this. But, this is easy to do, because all day long in our clinics we see and hear the cases where there is correlation, because the people seeking us out are in fact "symptomatic" patients and not uninjured runners, so it is easy to lean in one biased direction from our end. Though, it bodes the bigger question off of this following statement, "uninjured runners normally experience small alterations in kinematics when running with typical levels of exertion", as to whether in time, these small alterations might lead to a symptomatic state. One can easily theorize that it is in fact this time variable that eventually leads these small alterations towards bigger ones that might become symptomatic. After all, every avalanche starts with a single snowflake, no offense to the snowflakes out there.

Shawn Allen, the gait guys

References:

1.  J Sci Med Sport. 2014 Jul;17(4):419-24. doi: 10.1016/j.jsams.2013.05.013. Epub 2013 Jun 19.
Kinematic changes during running-induced fatigue and relations with core endurance in novice runners. Koblbauer IF1, van Schooten KS2, Verhagen EA3, van Dieën JH2.

2. J Orthop Sports Phys Ther. 2008 Aug;38(8):448-56. doi: 10.2519/jospt.2008.2490. Epub 2008 Aug 1.
Proximal and distal influences on hip and knee kinematics in runners with patellofemoral pain during a prolonged run. Dierks TA1, Manal KT, Hamill J, Davis IS.

3. J Biomech. 2010 Nov 16;43(15):2993-8. doi: 10.1016/j.jbiomech.2010.07.001. 
The effects of running in an exerted state on lower extremity kinematics and joint timing. Dierks TA1, Davis IS, Hamill J.

4. Gait Posture. 2014;40(1):82-6. doi: 10.1016/j.gaitpost.2014.02.014. Epub 2014 Mar 4. 
Do novice runners have weak hips and bad running form? Schmitz A1, Russo K1, Edwards L1, Noehren B2.

5. J Strength Cond Res. 2016 Oct;30(10):2907-17. Do Running Kinematic Characteristics Change over a Typical HIIT for Endurance Runners?
García-Pinillos F1, Soto-Hermoso VM, Latorre-Román PÁ.

Step rate to change foot strike?

Do you do gait retraining? Have you thought about manipulating step rate to change foot strike? If not, you may want to check this out. 

"The intent of our study was to determine whether step-rate manipulation alone was enough to change foot-strike pattern in shod recreational distance runners. We found increasing step rate above the runner’s preferred rate by 10% was successful in changing foot-strike pattern from a heel-strike to a midfoot- or forefoot-strike pattern in 17.5% of the runners, while increasing step rate by 15% changed foot strike pattern in 30%. These results suggest step-rate manipulation alone may be an effective way to change foot-strike pattern in a small percentage of shod distance runners."

http://lermagazine.com/…/step-rate-manipulation-and-foot-st…

“When you run up a hill, most of the cross over gait disappears. Runners will tend toward beautifully stacked lower limb joints.”- Dr. Allen

Are people running up a hill more likely to tend towards a cross over gait style, in other words tend toward a more narrow gait step or a wider gait step ?

Watch people run up hill closely. Even if they are cross over (narrow foot fall) runners, when running up hills a few things will negate much of the narrow foot fall.

1- Running up hill requires more gluteals, more power is needed for all that extra required hip extension to power up the hill. More gluteal max use can, and will, spill over into the posterior fibers of the gluteus medius and this will tend to abduct the leg/hip and reduce some of the cross over tendency.

2- When one runs up a hill, there is a forward pitch of the upper torso, often with a some degree of forward pitch occurring at the hips. More importantly, because one is running up hill, they are stepping up and so more than normal hip flexion is necessary than in normal running. The forward pitch of the body and the greater degree of hip flexion is the culprit here. If the hip/leg is adducted in a cross over style, adding this to a more than normal flexing hip, it will create a scenario for anterior hip impingement and risk of femoral acetabular impingement (FAI) syndromes. Go ahead, test it for yourself. Lie on your back and flex your hip, drawing your knee straight up towards your shoulder.  Pretty good range correct ?  Now, flex the hip drawing your knee towards your navel, adducting it a little across your body. Feel the abrupt range of motion loss and possible pinch in the front of the hip ?  FAI.  This is what would happen if you utilized a cross over gait, narrow foot strike gait. The goes for mountain/sleep hill hikers as well. 

This is why, if you are a narrow foot striker, a near-cross over type of runner, you will see it disappear when you run up hills.  

If you get anterior hip pain running up hills, force a wider step width and reduce the possible impingement at the anterior hip joint. Just make sure you have enough ankle dorsiflexion to tackle the hill in the first place. If not, you may welcome some foot and ankle stuff to the table along with the hip.  

Likely obvious stuff to most of the readers here, but sometimes it is nice to point out the obvious.  Hills, just because they are there, doesn’t mean you have the parts to run them safely.

Dr. Shawn Allen

“those with chronic neck pain demonstrated a narrower step width, a shorter step length and slower gait speed during walking with the head movements and at maximum speed” -  Uthaikhup et al. study:

Head movement and Gait Parameters:

By now you should have a good grasp of the global impact of gait and how it presents and translates in everything we do. It is how we move through this world, and everything we do, and everything that has happened to us, impacts our gait. And, our gait impacts things in turn, from our mental state to how we think and act.  

By now, if you have been with us here on The Gait Guys long enough, you know that with the tremendous proprioceptive impact of the system from the cervical spine, that neck pain can influence sensorimotor function and thus motor function. However, little is known about the effects of head movement and walking speed on gait characteristics in patients with neck pain.

From the Uthaikhup et al. study:

Patient sample:  20 women aged between 18 and 59 years with chronic neck pain (>3 months) and 20 healthy controls of similar age, weight and height

Indexes used: Neck Disability Index and Visual Analogue Pain Scale.

“The experiment consisted of two walking sessions. The first session included walking with head straight, head up-down, and head turns from side to side. The second session included walking at comfortable and maximum speeds. Each trial was performed twice. Gait parameters measured using GAITRite walkway system were step length, stride length, step time, stride time, step width, cadence and gait speed.”

According to this study, the clients with chronic neck pain showed several changes in how they implemented their gait. They displayed step width narrowing, a reduction in step length and speed of gait, and even an overall reduction in gait speed when neck movements were induced or encouraged or when there was pain..

As Uthaikhup et al. summarized, “The results suggest that patients with chronic neck pain have gait disturbances. This supports the notion that assessment of gait should be addressed in patients with persistent neck pain.”

You have to know your gait norms to understand abnormals. We have written about other parameters that affect gait speed, step length and width here on the blog. Here is one more parameter for you to store in your noggin. It is all connected. So, when you goto your gait analysis guru, ask them if they are going to clinically assess your painful neck as part of the gait analysis (be prepared for the “deer in the headlights” look).

Dr. Shawn Allen, one of the gait guys

Reference:

Man Ther. 2014 Apr;19(2):137-41. doi: 10.1016/j.math.2013.09.004. Epub 2013 Sep 27.The effects of head movement and walking speed on gait parameters in patients with chronic neck pain. Uthaikhup S, Sunkarat S, Khamsaen K, Meeyan K, Treleaven J.

Heat Exertion and Gait Decline

Changes in gait characteristics are found when exertional heat stress is experienced during prolonged load carriage.  As heat stress increased, step width decreased while percent crossover steps increased. Reduced stance time variability, step width variability, and percent crossover step were observed.  These are frontal plane gait parameters for the most part. 

Think about these things during your long summer run or as you go deeper into those last miles of your long run.  Simple muscular fatigue in the frontal plane hip-pelvis stabilizers are going to render the same results.  This is quite possibly why many problems and injuries crop up in the latter miles of your run. 

Reference:

Gait Posture.

2016 Jan;43:17-23. doi: 10.1016/j.gaitpost.2015.10.010. Epub 2015 Oct 23.Using gait parameters to detect fatigue and responses to ice slurry during prolonged load carriage. Tay CS, Lee JK, Teo YS, Q Z Foo PTan PM, Kong PW

Does slowing gait increase gait stability ?

As this study suggests, it has been difficult to find studies that establish a clear connection between gait stability and gait speed. One can easily assume that slowing down increases stability, we do it on slippery surfaces, we do it when a joint is painful, even the elderly do it naturally everyday. Walking speed, step length, step frequency, step width, local dynamic stability , and margins of stability were measured in this study below. It was found that the subjects did not change walking speed in response to the balance perturbations rather they made shorter, faster, and wider steps with increasing perturbation intensity. They became locally less stable in response to the perturbations but increased their margins of stability in medio-lateral and backward direction. 

So what did they conclude ?  Here are their words,“In conclusion, not a lower walking speed, but a combination of decreased step length and increased step frequency and step width seems to be the strategy of choice to cope with medio-lateral balance perturbations, which increases Margins of Stability (MoS) and thus decreases the risk of falling.”

It is my assumption, and this just seems logical, that if the perturbations were to continue constantly, that one would slow the gait speed to reduce the need for these shorter, faster and wider steps. 

Dr. Shawn Allen

http://www.ncbi.nlm.nih.gov/pubmed/22464635

Gait Posture. 2012 Jun;36(2):260-4. doi: 10.1016/j.gaitpost.2012.03.005. Epub 2012 Mar 29.Speeding up or slowing down?: Gait adaptations to preserve gait stability in response to balance perturbations.Hak L¹, Houdijk H, Steenbrink F, Mert A, van der Wurff P, Beek PJ, van Dieën JH.

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

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Annweiler C

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Dubost V

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Bridenbaugh S

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Herrmann FR

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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

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Tillman MD

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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

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Stierwalt JA

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