You are mostly likely not getting to your big toe at push-off if you are doing this.

You are mostly likely not getting to your big toe at push-off if you are doing this. Look at the shoe wear patterns in the photos below, they are not this runners, but another runner who also has a cross over gait. And, if you have a painful big toe, you will do it as well. Oh, and Head-over-foot related, yup. Read on . . .

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Yes, the cross over gait. Yes, when you are into a cross over gait you are most certainly head over foot. And that is most likely not a good thing.

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If you are not closer to stacking the hip over the knee, and knee over the foot (like in the photo "SUI" bib runner) you are not likely getting to much of your big toe at terminal stance loading, when you could be getting more power at push off.
Said another way, if you are attacking the ground with the feet closer together, as if you are running on a line (as in the photo) you are going to be more on the outside of the foot (note the lateral foot contact), show a similar wear/loading pattern as in these shoes, and hardly load the medial foot tripod effectively.
Go ahead, walk around your office or home right now . . . . with a very narrow step width and see how little you can load into the big toe-medial foot tripod (note how little effective glute engagement you get as well by the way. there is a reason why there is a limit to the effectiveness of a very narrow step width). Then, walk with a wider step width, note the easier more effective big toe-medial tripod loading, and, note the glutes come into play much more profoundly.
Thus, head over foot/cross over gait is foolish for effective gait. You have a big toe, don't you wish to use it ? One has to find that balance between an economical step width that still allows an effective toe off event in walking and running. A very narrow cross over-style gait does not afford us this.
So, should it be any surprise to any of us that someone with pain in the big toe or medial tripod complex will choose a narrow step width to avoid the painful loading ? No, no surprise there at all.
We have been writing about the cross over gait for 10 years, bringing little pieces of research to the forefront to prove our theories on it as the research presents itself. We first brought it to you with our 3 part video series here. Search our blog, type in "cross over gait" into the search box on the site www.thegaitguys.com and get a LARGE coffee before hand, you are going to be reading for several hours.

https://www.youtube.com/watch?v=LG-xLi2m5Rc
https://www.youtube.com/watch?v=WptxNrj2gCo
https://www.youtube.com/watch?v=oJ6ewQ8YUA

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Where do you want to load your foot in relation to your center of mass ?

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Who do you want to be ? The guy loading his head over his foot
(narrow step width), or the gal loading the head and COM inside the foot (less narrow step width) ?
It is not hard to guess who is gonna be faster and more powerful from these photos. The lady is stacking the knee over the foot, the hip over the knee and stabilizing the hip and pelvis sufficiently and durably to keep the pelvis level for the next powerful loading step, and the other is flexion collapsing into the stance phase knee, insufficiently loading the hip and thus dropping the opposite side pelvis. He is not stacking the joints, there is a pending cross over (look at the swing leg knee approaching midline with barely any knee spacing, thus guaranteeing a cross over step or at the very least a very narrow step width.)
Sure, some one is going to say one is a distance runner and the other is a sprinter. Yes, and our point is that the sprinter is not head-over-foot, the one with all the highly suspect flaws is head over foot ! Wider step width means more glutes. Go ahead, walk around right now with a very narrow step width and see how little efficient glute contraction you get, then walk with a notably wider step width, and you will see wider means more glutes. Keep your COM moving forward, not oscillating back and forth sideways over each stance foot, that is a power leak.

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The distance runner is showing sloppy in technique. Say what you want, but one of these runners is weak and very likely at greater risk for injury, the other is strong and durable, and likely at less risk for injury.
If you ask us, but what do we know . . . .
So, again, was ask . . . . which one do you want to be ?

Running paths and the cross over gait and narrow step width.

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This is a walking/running path. Do the runners on this path only have one foot? No, of course not, they are running on a line. Yes, we cannot get away from this cross over gait, a terribly narrow based gait pattern.
Is it economical? Likely.
Risky ? Possibly.
Do we know that this angled attack of the foot towards the mid-line asks more from the frontal plane stabililzers in the hip and core ? Yes, research has shown this.
Do we know that the gluteus medius helps with foot targeting? Yes, research again shows this, and thus a weak gluteus medius will enable a more medial targeting. Lesson: the gluteus medius helps with foot targeting on the swing leg, and hip stability on the stance leg.
With a Cross Over gait, Do we know that we need better control of internal spin of the limb, better foot pronation durability and many other durable abilities that we might not need so much of if we were better stacking the joint? Again, yes.

We confirmed with the reader who sent the photo that this is not a bike path (at this location this path is for walking folks, the bike path is adjacent to the parking lot).
The reader (Terry B. (thank you Terry)) astutely mentioned that people are walking on a line. If they had some spacing, step width, there would be 2 trails and a tiny patch of grass between them.

But, now, this line, the line is a queue for others to "walk the line" and join the cross-over nation.
We have written gobs of articles on this cross over topic, the few benefits, the teeter-totter "risk / reward" factor, the drawbacks and injury susceptibility factor and we have spoken about it on our podcast probably 100x. IF you wish to entertain that rabbit hole of knowledge, just goto our website and type it into the "search" box. "cross over gait"

Arm swing, cross over, head over foot?

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Here is a Birdseye view of someone in full stride gait. The left leg and the right arm are into flexion and external rotation.
The right leg and left arm are into extension and internal rotation.
We discussed this in depth on our lecture on wednesday night.
These counter movements drive,and are driven by, the anti-phasic properties of normal gait.
Now, lets posture some thoughts with the head-over-foot mentality (which we do not subscribe to(listen to podcasts 135-136)). . . . You can see the clear relationships here of coupled motions of the limbs. Now imagine that you forced a cross over arm swing, pumping arm Swing across your body. This is shoulder/arm adduction. So what do you think is likely going to happen in the lower limb? Yes step width narrowing, i.e. crossover gate/Leg adduction. By forcing the arms to cross the midline you are strongly encouraging the legs to do the same thing. As we have discussed many times previously, the arms can shape the movement of the lower limbs even though the lower limbs run the primary patterns of which the arms are driven from. So if you want a crossover gait , which we have for years documented research showing biomechanical challenges, and something we see many injuries driven from, go ahead and coach and train your arm swing across the body.

Your center of mass in relation to foot strike position.

For those arm swing/pulsers/ COM and head over foot folks consider some more research below.
Let the CNS drive the show, it is what it is there for . . . The leg motor patterns are dominant, the arms are passive and "shape" and influence the leg swing as a balance and ballast effect. As we discuss in an upcoming podcast, to cross the arms in a pumping motion across the midline of the body means one has to have compromised scapular mechanics (mostly protraction) to afford that much humeral adduction. This means we are forcing thoracic rotation as well. This means we are reversing what we know is more true, that "arm motion is driven passively by rotation of the thorax (Pontzer et al., 2009), an idea which is supported by shoulder muscle EMG data" (and not thoracic rotation by arm swing). Why would we try to create more unnatural axial spin through the spine when we are actually trying to move forward in the sagittal plane? Why would we try to force more rotation through the spine when the function of the thoracopelvic canister (ie. the core) is to stabilize rotational /angluar momentum? Hmmmm, things to ponder.

"Previous modelling studies have clearly shown that motion of the arms effectively counterbalances the angular momentum of the lower extremities during running (Hamner & Delp, 2013; Hamner et al., 2010). It has further been suggested that arm motion is driven passively by rotation of the thorax (Pontzer et al., 2009), an idea which is supported by shoulder muscle EMG data, consistent with the shoulders as spring-like linkages (Ballesteros, Buchthal, & Rosenfalck, 1965). Our data are con- sistent with this idea, showing motion of the thorax to be in the opposite direction to that of the swinging leg. Pontzer et al. (2009) also suggested that motion of the thorax is driven passively by motion of the pelvis. However, our data shows that the thorax reaches its peak angular velocity earlier than the pelvis, indicating that thorax motion is not completely passively driven by pelvic movements."

-S.J. Preece et al. / Human Movement Science 45 (2016) 110–118

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.

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.

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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.