How robust is human gait to muscle weakness?→

Below you will find a link for the 2012 article in Gait Posture entitled “ How Robust is Human Gait to Muscle Weakness?”

Today’s Take Home Points are:

1. Proper technical form in walking and running is critical. Everyone talks about it at the ground level assuming we are all idiots.  No one is getting down to the roots of the problems and solutions like we try to do.  This means reducing Cross Over gait pathologies which we have shown you previously. 
2. Attempt to maintain clean movement patterns free from compensations. For one,  make sure you have sufficient ankle rocker (dorsiflexion bend). 
3. Make sure your abdominal muscles and core are symmetrical and strong. Obliques are key but not exclusively so.  They will make sure that your initial hip flexion comes from them and not the hip flexors !
4. Do your glute work to ensure your glutes are in charge of hip extension and not your quadriceps.
5. Make sure you are not a victim of compensations such as overactive hip flexors, weak hip abductors and premature calf engagement.

Now, lets get into the details, this summary is pretty soft.

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We are ordering this article to see its specifics so stay tuned for any other info. Here we dissect the articles main principles to put it into terms that might serve you well as a walking or running human.

Lets start with a great quote from Basmajian in Muscles Alive,

Locomotion is “the translation of the center of gravity through space along a path requiring the least expenditure of energy. Pathologic gait may be viewed as an attempt to preserve as low a level of energy consumption as possible by exaggerations of the motions of the unaffected levels. When a person loses one of the six determinants of human gait compensation is reasonably effective. Loss of two determinants makes effective compensation impossible; the cost in terms of energy consumption triples adn apparently discourages the patient to the point of his admitting defeat."  Basmajian, 1953, Muscles Alive: Their Functions Revealed by Electromyography.  (Yes, it is 60 year old statement, but we use this book all the time because it is one of a kind and this guy was ahead of his time. His information is frighteningly accurate even on today’s research terms.)

What this article seems to indicate is that weakness in certain muscles has some predictors.  The article inquires, "how much weakness can be tolerated before normal daily activities become impaired?” In theory what they were looking at was a simple principle suggesting that there is a kind of tipping point for muscle weakness before there is sufficient weakness to require a gait compensation pattern to protect the joints and attempt to preserve the motion of gait. 

What the study found is that the muscles of hip extensors and knee extensors (glutes and quadriceps are assumed here) are particularly robust and resist weaknesses. These are sagittal (forward progression) muscles and are quite necessary for gait and running movement. 

In contrast the study indicated that gait is most sensitive to weakness of plantarflexors, hip abductors, and hip flexors.

So, how might this be interpreted ?  Well, lets start with the hip abductors. These are the gluteus medius muscles for the sake of generality.  These protect the frontal plane and help keep the pelvis neutral. They protect you from the Cross Over gait we have talked about over and over again in previous blog posts and YouTube videos.  Without proper frontal plane stability gait pathologies arise (not to say this is the only source however).

Now lets talk about the hip flexors. This muscle group is every therapists gem to talk about. There always seems to be a runner or patient talking about how their massage therapist,physical therapist or athletic trainer has told them that their hip flexors are tight, weak or filled with trigger points.  We do not dispute their findings here. But what we wish for you is to use logic based on THE FACTS. Most of these people will be alarmed to find out that a main function of the hip flexors is not to initiate hip flexion.  NO ! Say it ain’t so Jack !  Well the truth is that the psoas  muscles are in a big way hip flexor PERPETUATORS, not INITIATORS.  The abdominal muscles are the first muscles to initiate hip flexion via derotating the obliqued pelvis at heel rise.  It is only once the pelvis is moving forward with the pendulum leg following forward that the hip flexors engage to perpetuate the limb flexion at the hip.  Remember, once the leg is in swing phase much of the hip flexion movement is PASSIVE from momentum ! (We will save you from another Newton’s Law diatribe here).  So, it might be safe to say that whatever “your people” are finding are results and consequences to impaired use of the core to INITIATE proper limb/hip flexion. According to this journal source: “Psoas major works phasically: (1) as an erector of the lumbar vertebral column, as well as a stabilizer of the femoral head in the acetabulum at 0 -15 degrees flexion at the hip joint; (2) less as a stabilizer, in contrast to maintaining its erector action, at 15 -45 degrees; and (3) as an effective flexor of the lower extremity, at 45 -60 degrees."  This study seems to support that the psoas is not an initiator of hip flexion, rather it engages at 45 degrees making it a clear perpetuator.

Now lets dialogue briefly on the plantarflexors assuming they mean the gastrocsoleus complex.  All we are willing to say here (because this is a project we are working on) is that when the gastrocsoleus are not used correctly to drive forward progression they may serve to lift the person (this comes with premature heel rise and thus premature calf firing). This can lock out further ankle dorsiflexion range and thus hip extension range. Thus, limiting the ability to gain a sufficient hip extension-pelvic rotation to enable sufficient range for the abdominals to serve as hip flexor initiators and possibly calling on the psoas and other hip flexors to prematurely engage to initiate the motion. 

How do we summarize this article ?  The journal abstract did it nicely for us. "Compensations are generally inefficient, and generate unbalanced joint moments that require compensatory activation in yet other muscles. As a result, total muscle activation increases with weakness as does the cost of walking.” And it will go as well for running in our opinion.

Again, the Take Home Points are:

1. Proper technical form in walking and running is critical. Everyone talks about it at the ground level assuming we are all idiots.  No one is getting down to the roots of the problems and solutions like we try to do.  This means reducing Cross Over gait pathologies which we have shown you previously. 
2. Maintain clean movement patterns free from compensations. Thus, make sure you have sufficient ankle rocker (dorsiflexion bend). 
3. Make sure your  abdominal muscles and core are symmetrical and strong. Obliques are key but not exclusively so.  They will make sure that your initial hip flexion comes from them and not the hip flexors !
4. Do your glute work to ensure your glutes are in charge of hip extension and not your quadriceps.
5. Make sure you are not a victim of compensations such as overactive hip flexors, weak hip abductors and premature calf engagement.

Who are we ? Shawn and Ivo, The Gait Guys. Two doctors dedicated to challenging the myths and lies out there in the world and on the internet on gait and running from the perspectives of orthopedics, neurology and biomechanics. 

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Gait Posture. 2012 Feb 29. [Epub ahead of print]

How robust is human gait to muscle weakness?

van der Krogt MM, Delp SL, Schwartz MH.

Source

Department of Rehabilitation Medicine, Research Institute MOVE, VU University Medical Center, Amsterdam, The Netherlands; Department of Biomechanical Engineering, University of Twente, Enschede, The Netherlands.

Abstract

Humans have a remarkable capacity to perform complex movements requiring agility, timing, and strength. Disuse, aging, and disease can lead to a loss of muscle strength, which frequently limits the performance of motor tasks. It is unknown, however, how much weakness can be tolerated before normal daily activities become impaired. This study examines the extent to which lower limb muscles can be weakened before normal walking is affected. We developed muscle-driven simulations of normal walking and then progressively weakened all major muscle groups, one at the time and simultaneously, to evaluate how much weakness could be tolerated before execution of normal gait became impossible. We further examined the compensations that arose as a result of weakening muscles. Our simulations revealed that normal walking is remarkably robust to weakness of some muscles but sensitive to weakness of others. Gait appears most robust to weakness of hip and knee extensors, which can tolerate weakness well and without a substantial increase in muscle stress. In contrast, gait is most sensitive to weakness of plantarflexors, hip abductors, and hip flexors. Weakness of individual muscles results in increased activation of the weak muscle, and in compensatory activation of other muscles. These compensations are generally inefficient, and generate unbalanced joint moments that require compensatory activation in yet other muscles. As a result, total muscle activation increases with weakness as does the cost of walking. By clarifying which muscles are critical to maintaining normal gait, our results provide important insights for developing therapies to prevent or improve gait pathology.

Tibialis posterior

A question from one of our readers:

Hi guys,

What are your favourite tib post strengthening exercises or do you usually stay with the anterior strength work?

Thanks

D

Our Response:

Hi,
Thanks for your question. As you know the tibialis posterior muscle from the interosseous membrane, lateral part of the posterior surface of the tibia, and superior two-thirds of the medial surface of the fibula. It travels between the flexor digitorum longus and flexor hallucis longus to insert into the tuberosity of the navicular, cuneiforms, cuboid, and the bases of the 2-4th metatarsals.

The function of the tibialis posterior is one of ankle plantar flexion, calcaneal inversion and plantar flexion as well as stabilization (through compression) of the first ray complex (talus, medial cuneiform, navicular and base of the first metatarsal). It acts additionally to help decelerate subtalar pronation. Further stabilization of the midfoot comes from smaller tendon slips inserting onto the other cuneiforms, metatarsals, the cuboid and the peroneus longus tendon.

The more common problems that can occur with the tibialis posterior complex are those of muscular strain, tendonitis, tendon insufficiency (stretch) and partial or complete tears. Excessive or prolonged pronation causes excessive dorsiflexion of the distal first ray complex, increased pronatory effects, and as discussed above, dysfunction of the 1st MPJ joint. The dorsiflexed 1st toe will compromised the efficiency of the windlass mechanism which “winds up” the plantar fascia, properly positions the paired sesamoids, and thus limit effective dorsiflexion of the 1st MPJ. This dorsiflexion of the first ray requires the tibialis posterior to undergo excessive eccentric load for a longer period of time, thus placing more stress on the tendon and muscle belly.

Clinically we find that more people are flexor driven. Therefore we work quite a bit with increasing extensor function, thus a lot of our rehab protocals involve strengthing Anterior Tib as opposed to Posterior Tib. To this one must ask what is your criterior for strengthening the posterior tib, if over pronation or navicular drop has led you to this conclusion then you may want to reexamine the clinical findings for what muscles may actually be involved.

That being said, there times when it is clinically necessary to strengthen the Posterior Tibialis muscle and we like the following exercises

1. Single Leg Balance with Arch Supports:
Begin standing on one foot. Attempt to raise the medial longitudinal arch and hold in tact while maintaining the body stable over the foot.
2. Single Leg Balance with Arm Swings
Perform the exercise above and add to it multi planar arm swings while maintaining medial arch integrity and balance. Cross body arm swings that generate torso rotation, and simulated axe and pitching motion with each arm are effective motions to use.
3. Seated Forefoot Adduction and Inversion
This exercises utilizes some sort of resistive device such as a theraband that will wrap around the forefoot to attach somewhere lateral to the body creating lateral resistance. while stabilizing the ipsilateral knee with the contralateral hand the exercise is performed by adducting the forefoot against resistance towards the midline.
4. Inverted Calf raises
This exercise is performed standing. it should be started as a double support exercise and can be transitioned into a single support for added challenge. the exercise is performed by performing a standard calf raise with or with out Y-axis resistance and adding an inverted moment at the apex of the raise and then lowering back down.
5. Closed Chain Unilateral Supination
Standing on one leg on a step with the knee slightly flexed and the medial border of the foot over the edge of the step. Exercise is performed by lowering and lifting the arch from pronation to supination.

6. Now perform the sequence with appropriate arch intergrity WITHOUT the arch supports

These exercises should get you started. Good luck and let us know if you have any other questions.

The Gait Guys

In this great little slow mo video we see some things. Do you ? … The Perfect Runner.

1. First clips….. awesome toe extension through the entire swing phase all the way into early contact phase.  You have read here before on our blog entries how critical toe extension is for stable and optimal arch contruction prior to foot loading. Suboptimal arch height can mean that pronation loading occurs in a suboptimal foot tripod posturing and can mean difficulties controlling the normal end point where pronation should stop and convert back into supination to ensure rigid toe off.  (It is kind of like two runners in a 100m sprint. One starts at the line off the blocks and the other gets to start 1 second earlier 10 meters back from the line and gain speed towards the line before the gun goes off.  This is what it is like to start pronation prematurely, or with a suboptimal arch, the starting line where things are fair to all parts has been moved. The foot (the other guy in the race) doesnt have a chance.  Maybe a bad example but you catch the drift we’re surfin’ here.)  Back to our point, Niobe has great running form and great technicals.  Great midfoot strike, yes a little forefoot here but that is what happens when you are barefoot naked on hard surfaces. You have to get good form before you can clean up the technicals.  We spend alot of time on the technicals of running once form is clean. It is what makes the difference between 2nd place and a winner. And it is these little things that mushroom into nagging injuries over time.  We cannot express enough how important toe extension range and strength is for proper foot function and a strong neutral foot tripod.  We rarely have to address long toe flexor strength, short flexor strength yes, but not long.  Toe curls, towel scrunches, picking up stuff is not on our list of homework.

2. Second clip. He is skirting the issue of cross over without going too far. He could do a bit better but all in all pretty decent.

3. Emmanual Pairs, big dude ! No cross over. Awesome form.

4. Krysha Bailey. Long jumper. As with all sprinters, no cross over, beautiful form.

Just some easy topics and viewing for a Saturday blog post.

Have a good day brethren !

Shawn and Ivo

Friday Follies. Time to revisit George Costanza’s strength shoe !

thanks for the idea RC !

During a recent trip to the zoo with the family, I noticed this young lady walking in front of me (yes, We ALWAYS have a camera with us and YES, We ALWAYS look at everyone’s gait and YES, we really are that geeky).

Watch the clip a few times and note these points about the gal on the left; keep in mind, she could have hip or muscle pathology as well

• notice the subtle toeing in (decreased progression angle) of the feet, most likely due to internal tibial torsion
• notice how she doesn’t have her shoes tied; this would necessitate her clenching or clawing her toes to keep her shoes from falling off. This inhibits the activity of the glutes and causes her to have to extend from the hams and lumbar spine; as a result, note how straight she keeps her legs when ambulating
• there is little to no ankle rocker; she goes from heel rocker to forefoot rocker
• premature heel rise
• due to the lack of hip extension and decreased activity of glute max, note how she “rotates” around each leg
• how about that cross over gait?

Fixes?

For starters:

• tie your shoes
• 1 legged standing exercises, being careful to keep hips level and not have a pelvic shift
• walk with toes up or slightly extended during all phases except for that brief moment during midstance where you need the toes for balance and ground purchase
• shuffle exercises to engage glute max
• never wear pants that are sooooo tight that you cannot generate normal fluid gait

Ivo and Shawn…The Gait Geeks…We leave no gait unanalzed…even at the zoo. Watch it; we may have YOU on film!

Retail Focus: The Toe Box

(3 photos today, hover over the pic to see the slidebar cursor)

Shoes that are too tight in the fore foot inhibit motion. Just like anything else; “if you don’t use it…you lose it”. That goes for forefoot mechanics as well. Shoes probably do not cause bunions, but they can contribute to bad mechanics, which CAN cause bunions. Today’s retail focus will be on toe boxes.

The toes are designed to work as a team, and that team seems to work best with plenty of room to “stretch out”. We haven’t found a study to say that footwear causes foot problems, but there is at least one that says it can aggravate them. High heels don’t count; we have covered that in other posts,

From our forthcoming shoe fit certification program, we can note the following points:

• The toe box should have ample room to prevent crowding and pressure on the metatarsal heads.
• When measuring feet, remember “splay happens”’ the foot is wider and longer when weight bearing (standing) and more so at the end of the day (yes, your feet are larger in the evening).
• use  the larger of either sole or ball length (when using a Brannocks Device). When in doubt, size up!
• Make sure the toe break of the shoe (where the shoe bends in the forefoot when pressure is applied to it) is at the joint of the big toe (hallux)
• Make sure any siping or creases in the sole of the shoe near the forfoot line up with the junction of the metatarsal heads and phalanges (at the base of the toes)

Think about shoes with generous toe boxes: Altra, Keen, some Merrels, or brands that offer width sizing.

The Gait Guys….Yes, we do shoe fit too. Soon to be released; the most comprehensive shoe fit certification program ANYWHERE. Watch the blog, our Facebook page and the  website for the launch announcement….

Pictures compliments of Altra Running and Dr Mark Cucuzzella

Under Armor mouth Guards: Neuromechanics?→

This week in neuromechanics weekly, we will look at the concept or preloading motor neuronal pools. A reader asked if we could look at the above link (click title) and offer some clinical commentary and some rather bold statements

Here are our thoughts:

The findings they speak of are not surprising at all…

The Temporomandibular joint (TMJ) is blessed with many mechanoreceptors and receives innervation from Cranial Nerve V (trigeminal nerve) and the upper cervical spine. There is physiological overlap through the trigeminocervical nucleus (in the upper midbrain or mesencephalon, the principal sensory nucleus) which receives the same innervation from the trigeminal nerve distribution and the upper 4 cervical neuromeres(nerve levels) (so double input into same pathway). Nicoli Bogduk published abody of research on this, along with Susan Lord and Leslie Barnsley.

The upper 4 cervical nerve root levels also directly input into the flocculonodular lobe of the cerebellum (which coordinates alot of motor activity, especially of axial extensor muscles). This preloads the motor neuronal pool (just like contracting your muscle slightly, or clenching to get a better response from a reflex exam). By optimizing input (through a bite guard), you optimize mechanoreception, which optimizes cerebellar activity, which in turn pre loads the motor neuronal pool.  You would get SIMILAR ( and better tasting!) results with having them clench or bite down on gum, though not as good due to possible imperfect mechanics.

We have not seen all of the research but we are sure it is legit. It’s like an orthotic for the mouth. Keep in mind changing bite mechanics closer to symmetrical occlusion will be helpful ( ie. Orthodontics, invisalign etc).

There you have it. Next time you want to get some extra performance, or are trying to accomplish an especially difficult exercise, try clenching hard to preload those neuronal pools.

Ivo and Shawn…Preloading your neuronal pools to make learning this stuff easier for you….one pathway at a time.

Running, Einstein, Gravitational Push and Space. What do they have in common ?

WAIT !  Don’t watch the video just yet !  Read this first paragraph first !

Yes, you read it right. Gravitational PUSH.  Did your physics teachers mislead you ?  There is no such thing as Gravitational “Pull”.  Actually it is most accurate to say atmospheric push. Gravity does not pull us to the ground, space (as in the atmosphere) is pushing down on us. Space and time are curved and adjustable, Einstein proved this. You must be saying, “Oh Gait Guys, you are going way too deep now !”.  No, we are not. And you need to know this if you run or walk. It is simple. Your 5th grader will understand this and so should you !   Watch the video for a very nice explanation of what we are going to discuss today, atmospheric PUSH, start at the 3:30 mark for support for our point today.  If you choose not to watch this video today, it is your loss.  You will be depriving yourself of some of the most important information and logic there has ever existed in science. There is a big difference between pull and push.  Ask anyone who has had a car breakdown and had to push it off the road. Ask any weightlifter as well.

What does this have to do with running, walking and gait ?

Well, it is pretty simple.  This is yet another reason why posture is dependent upon the extensors such as the gluteals, the quadriceps, the cervical spine extensors, the thoracolumbar paraspinals, the abdominals etc.  These muscles must be strong enough to resist the push of Space down upon our bodies. Think of it this way, what muscles would have to work harder and be more isometrically and eccentrically strong and endurance trained if you had to carry a 100 pound person on your shoulders all day ?  It is much the same as if you were carrying a bunch of extra winter fat on your body. You will need more of these extensors otherwise you will begin to break down into compensations. 

With the natural motion of pronation during impact loading we need to dampen the internal spin of the hip, femur and tibia to resists the pronatory forces from space pushing down on us. 

So, our neuromuscular system has evolved to resist this push, and that job lies largely with the antigravity extensor muscles, which keep us upright. The elderly eventually begin to lose this battle as they weaken and posturally decompose. These muscles are powered by a special part of our our brain, largely the cerebellum, assisted by the vestibular apparatus (inner ear). Remember that there are 3 systems that keep us upright; vision, the vestibular system and the proprioceptive system. The interplay of these 3 systems is what Newton was trying to figure out and Einstein was eluding to.

This is one of the reasons orthotics (for the long term) often, but not always of course,  do not make sense.  Space pushing down on us and thus space pushing our body mass down onto our tri-arched foot (what we have come to understand as gravitational pull, which is technically misspeaking of the facts) is a large part what creates the pronation; with the musculature of the lower kinetic chain assisting in slowing it.  Slapping an orthotic under the foot to resist this force is not a permanent solution; it is often a temporary fix to a long term problem. This returns us to the hypothesis of today’s post, gravitational pull or Space push. Which is smarter, pushing up against the downward pressure of Space push (orthotic) or finding a better way of using the body’s anatomy to pull up against it ?  Which makes us stronger and a better human and athlete ? Finding better skill, endurance and strength (there it is again, S. E. S.) in the anti-gravitational muscles if you will, such as the toe extensors, tibialis anterior and posterior and foot intrinsics as well as those muscles above that are not dampening internal spin (medial quads, gluteals, lower abdominals)  is the answer if you really want to fix it.  Often times, a stability shoe is much the same as the orthotic; it provides dampening and slows pronation, or “resists” the push of gravity. It can sometimes be helpful in the short term; creating mechanics that you do not have; but is seldom good for the long term (though in some cases they are necessary, we are not negating their occasional beneficial use). We just ask that you, or at least your orthotist,  use your/their brain when making that decision.

As we always say, there are so few people who truly understand the neuro-ortho-biomechanics of the human parts going into the shoe that we get  all caught up in the shoe as the solution.  The solution is S. E. S.  , if you still  have the anatomy to get there.

Shawn and Ivo ………. two Uber geeks today.  They are the kind of guys who keep neurology and physics textbooks beside the toliet rather than Sports Illustrated Swimsuit issues.  Hey, we try to keep it simple. We like to pick the low hanging fruit just like everyone else. But it is the higher hanging fruit that are often the gems.  Sure, space pushing down on us all can make it hard to get up that high to the good stuff…….but it is worth it when you get there.  Thanks for tagging along on this journey. If you are a regular reader,  reconsider your bathroom reading material if you haven’t already !

More on the “Earth” shoe

3.7 degrees. Who (besides maybe Kevin Bacon) would have thought a few degrees could make that much of a difference?

We don not doubt that the shoe helps you to burn more energy. You are walking up hill against your normal biomechanics. Inefficiency usually costs more energy.

Remember our friend “PRONATION”? It consists of dorsiflexion, eversion and abduction. SOME PRONATION is requisite for normal gait. It is one of the 4 shock absorbing mechanisms, along with ankle dorsiflexion, knee and hip flexion. (Midfoot) PRONATION begins from initial contact of the heel with the ground (loading response); friction of the heel on the ground causes the talus to slide anteriorly on the calcaneus and it then plantar flexes, adducts and everts to lower the midfoot. This goes on until MIDSTANCE, when the opposite leg begins to go into swing phase which initiates SUPINATION.

We remember PRONATION makes the foot into a “mobile adaptor” for shock absorbtion; SUPINATION makes the foot into a rigid lever for propulsion. The question is: “Why keep the foot in a position that would decrease biomechanical efficiency for ½ of the gait  cycle?”

We do not refute that the shoe does burn more energy. We agree that it will reduce the lordosis of the low back, which can be beneficial for spinal canal stenosis and a few other conditions which demand less stress on the facet joints. We like the wide (though not anatomic) toe box.

Negative ramp delta? We are not convinced this is great idea.

Ivo and Shawn. Triangular, pointy (but beautifuul and bald) heads (like a delta). Bringing you the facts so you can make better decisions.

In our series of questions we get…

Dear Gait Guys

I was reading an article the other day about the foot and intrisic muscles to gain more insight into the function and how to re-train these muscles. I am having a difficult time trying to give patients exercises for intrisic muscles when everyone seems to say something different. The most recent I have read is that the best way to retrain the lumbricals is stand on your toes and walk up steps. I can see some logic in this but also seems a very generic exercise and would encompass alot more flexor driven muscles that are likely already strong. I was wondering if you have a more specific exercise that would be simple and easy for patients to do?

Dear Lumbricals

We would have to agree with you that the exercise is very generic and would cause overuse of the flexors, though it would stimulate lumbrical function.

As you are aware, the lumbricals attach proximally to the sides of adjacent tendons of the flexor digitorum longus (with the exception of the 1st, which only attaches to the medial side) and attach distally to the medial aspect of the head of the proximal phalynx and continue on to the extensor hoods in toes 2-5 .

Their typical function is described as flexion of the proximal phalynx and extension of the proximal and distal interphalangeal joints. They have the unique ability to compress the metatarsal-phalangeal and inerpahlangeal joints. There is also a small adductory moment to counteract abductory shear, due to the tendon passing medial to the metatarsal-phalangeal joints (michaud). These are open chain functions. Unless you are in the habit of waving to people with your toes, they often are used quite differently. But this brings upa good point and excellent exercise we call “waving the toes”.

They are performed by holding the great toe in dorsiflexion (hopefully, without assistance) and flexing the other toes at the MTP joint, while keeping the PIP and DIP in extension. This requires and intact and functional EDL (with good motor control!)

Another exercise is sitting with the foot relaxed and concentrating on flexing the toes (2-5) without clawing (similar to above, without the Hallux extended.

Remember they work from mid to terminal stance, but you need to develop skill before endurance or strength.

We hope this helps, 

The Gait Guys

As a runner: To Cross-Over or not to Cross-Over ?   That is the question. Lets go back and talk about the Cross Over Gait again (yes, again). This is the next level.

*watch this video (link) and notice 2 things: 1. the size of the glutes on these amazing athletes and 2. pay attention to the few seconds at 1:32. No Cross Over gait anywhere.

If you look at any video on the web of ANY sprinter in competition from the front or back (sagittal progression), you will always see the knees and feet falling underneath the hips. Watch video above again and see this. You will never see a sprinter cross over like we see in many distance runners.  Why is that ? Here, look this video (link)  as well, at the 1:30 mark there is a great overhead view of the field, look for one of these fellas crossing over, you will not see it.  Here are starts out of the blocks, clear abduction (link) and no cross over, in fact there is more leg abduction separation coming out of a start to get more glute power (think of a skater, same thing).  Now get on YouTube and watch any distance race and you will have to work at finding non-Cross Over runner or at least someone who is at the tipping point. Everyone does it, but does that make it right ? Does it make it wrong ? Does it make them vulnerable to injury more ?  We think it does.

We believe to reduce injury the cross over needs to be corrected. However, in distance running less brute power is needed, we need to conserve energy so we need to dial to a more reasonable and economical and efficient running gear.  In distance athletes and your typical 20+ mile a week runner less gluteal power is needed, but most runners have just gone past that tipping point and get into under use and begin to cross over.  Lets see if we can expand on this theory a little more.

Well, there are no studies on this. As far as we know we are the only ones trying to solve this mystery of the tipping point cross over gait/run style. Go ahead, search on the web, we seem to be on a solitary voyage all on our own, thankfully we have our Gait Guys brethren (you guys !) with us.  It does however bode the question for us,  “Why are we able to get so many of these chronic distance runners over their injuries by addressing their Cross-Over Gait and its frequent weaknesses (gluteus medius/maximus/medial quadriceps), excessive pronation and their tightness’s (IT band etc). Why do our sprinters have an entirely different injury pattern  ?”  Sure the athletes are different and their events are different, that is the simple answer but it is not good enough.  One athlete is built for speed, the other built for distance and endurance. But there is something big here that needs all of our attention.

Here is the fundamental difference.  We get some vocal challenges particularly from distance runners (but less with time as our theory has yet been refuted) that the cross over is more efficient for a distance runner.  (Example of another great cross over here in case you are new to our work on this topic (video link)). We disagree, for now, until research can disprove our theory which has been several years in development.  The Cross Over Running form challenges the normal pendulum effect of the lower limbs and challenges the biomechanics of the hip frontal plane stabilizers, namely the gluteus medius (need a biomechanics refresher? , click here).  Why would you want to change the natural leg pendulum in a runner ? This is not good running economy, although you will have a fight on your hands if you ask a runner to convert to our anti-cross over gait and drag them from their deeply engrained and comfortable cross over running style ! Beware, they are going to tell you it doesn’t feel right, it is too hard, it feels awkward, “it cannot be right !"  Well, so does brushing your teeth with the opposite hand but that doesn’t make it wrong.  Our 3 part series on Cross Over Running is pretty thorough if you want to learn more, but this is not the place. We feel we have been pounding the floor on those issues long enough.

Here is our question, go and do your own observational work as well. 

Look at the glutes of sprinters (watch the main video with this post again), compare size ratio of glutes to quads. Sprinters have bigger glutes, sure they have massive legs but they have glutes to match that power.  Their glutes are in charge of their hip and pelvic mechanics. When there is mismatch there is often injury.

Distance runners have much smaller glutes, their buttocks are small, in some cases you wonder where it has all gone !  But their quadriceps are massive in comparison in many cases. It is clear that in most of the cases the ratio is not the same as in sprinters.  There is a mismatch. We like to say that their quadriceps are in charge of their hip mechanics, and are certainly not suited to do so.  Now, we know the argument that will arise, that being they are different activities and thus they should be different.  Our only argument there is that the quadriceps should not have such a dominance over the gluteal and hip biomechanics.  Watch our two part hip biomechanics videos on YouTube again.

When we put our distance athletes on our Total Gym slide-squat board to do primitive squat isolations the distance runners have a great deal of difficulty “getting themselves out of the quads and into the glutes”.  The sprinters automatically go right into the glutes, or clearly have a better time of finding the correct pattern in controlling hip extension and eccentric hip flexion during the decent of the squat. 

Here is the bottom line. The glutes should always be in charge over the quadriceps when it comes to hip biomechanics. Mess up this ratio and dominance and problems will occur.  This goes for both distance runners and sprinters, actually all human beings no matter what sport. It has become painfully clear that the cross over gait allows the leg pendulum to shift too far medially and this is controlled largely by the gluteus medius and its synergists on a neutral pelvis and stable core controlling it.  Crossing over is poor gait economy, you must block that faulty cross over collapse.  A good distance runner will come right up to the fence, to the tipping point, but not fall off the proverbial fence.  Go too far, and the injury clock starts ticking.  If you are a runner or even a distance walker and you are crossing over even a little, you need to correct this gait pathology in our humble opinion. You are just not using your glutes correctly and effectively.

( By the way, Here is a drill (link) not to do for a sprinter or any runner for that matter in our opinion, it is driving cross over both mentally and physically. If we had our way he would have run with his foot contact drifting to the outer limits of each marker maintaining a nice vertical pendulum of the limbs from the hip axis, we wouldnt have him run down the line.  We ask our runners to run on either sides of the lanes on the track, not between the lines and in the lane. It is a great place to start. It is just enough to get the feel right.  We know of two coaches doing this from our consultations with them, we know they are on a serious journey to championship seasons. And, when we walk onto their fields and we see all the runners running down the lines and not down the middle of the lanes we smile.  We know it looks crazy.  But sometimes crazy is right !

Shawn and Ivo.  Beating our bloody foreheads against the wall each time we see another cross over runner with hip, knee or foot issues.  You gotta fix the neuromotor pattern problem too !!!!!!!!!!  All the in-clinic rehab and physical therapy in the world will not stave off re-injury if the pattern is not corrected !

whew !  (thanks for hanging in there gang…..long post today !)

Hip Dancing gets this runner to the Olympics→

… and some of you thought we might be a few sandwiches short of a picnic when we talked about the value of, and tricks we use, incorporating dance moves into running rehab. Don’t lie, we know you were thinking it ! Remember our last post of 2011 on our experiences with this stuff ?
http://thegaitguys.tumblr.com/post/15029125468/this-may-be-the-last-blog-post-you-read-from-us

here is a video of the japanese runner doing his Curvy Dancing ?!     http://youtu.be/DvNW4yZNHgM

It wouldn’t be St Patty’s day with out a little gait humor.  Round them up little doggie !

cheers to ya all…….we raise a Black and Tan for ya’ll

Shawn and Ivo ……..gluten sensitive and expecting plenty of bloating and flatulence today. 

From Traditional trainers to minimalism…… so, what is the “earth shoe” then ? Will the fad return ? Will we see running shoes go this far ? Afterall, we are at zero drop now ?

So, we all have seen the trend……. minimalism is here and it is not a fad, it is a trend and it is here to stay. It is here to stay because it is not a fad like this shoe above.  The Earth shoe has made 2 resurgences in the last 4 decades. We are likely to see another very soon since this minimalism trend has occurred. Make no mistake though, the minimalism is not a fad, it is a trend and it will be staying. 

So, what is wrong with this shoe ?

Minimalism will remain because we are finally restoring the normal rear foot : forefoot parameters to what we were born with. We were born with the rear and forefoot on the same plane, flat on the ground.  This even playing field, or at least a return to it for many shoe manufacturers, allows the anatomy (both bone and soft tissues such as muscles) to again operate in the fashion it was designed.  Sure the “running form” changes everyone is promoting is important. It is critical to get into good form. But unless the foot’s parts are normalized to the optimal mechanics we were born with even running form changes will not correct 100% of a person’s mechanical issues. 

The minimalism is allowing the rear foot to drop down to the same level of the forefoot, the same operating plane.  This necessitates length in the posterior compartment (calf and achillies mechanism) which will enable the anterior compartment (tibialis anterior and toe extensors) to see more function and thus gain more strength.  This plays well into our long standing theories that stretching of the calf, albeit sometimes necessary to a point, is not the answer for tightness in the calf…..rather putting the foot in a posture to enable the anterior compartment will earn length in the posterior compartment.  Here comes another mantra we use in our offices……. “Gain Anterior strength to achieve Posterior Length”.  Merely stretching the posterior compartment to gain length does not afford anterior strength.  So, it depends if you want a temporary bandaid or a long term fix.  We opt for the fix which is why it is a rarity that you ever hear from us “Mrs. Jones, you need to stretch your calf”.  Instead we teach the solution.

What else comes to mind about minimalism.  Well, again take the shoe above to give an extreme example of what dropping the heel will do.  It will shift your weight bearing posture posteriorly. Go ahead…..stand on the ball of your feet….. your body mass shifts forwards, your low back might arch if you do not have enough abdominals.  IF you then drop the heel you will feel your body posture shift backward and you will feel more glute and more abdominal and neutral pelvis-core posturing. You will also feel a more balanced weightbearing between the forefoot and rearfoot. This is good. These are just some of the things that minimialism does.  There is alot more.  But those are for another time.

In the meantime. The earth shoe. It drops you into rearfoot negative. The rearfoot is lower than your forefoot.  Remind you of anything ? Yup, walking in the sand. The heel sinks more if you load it first.  This will create a drastic change in length-tension relationships between the calf and anterior compartment. It will load the anterior ankle (mortise joint) and can really challenge the shin muscles.  Ever get shin splints or soreness the next day after a long beach walk ?  There is your reason.  So, the Earth Shoe. It is not natural. It puts your rearfoot and forefoot on two separate planes of operation. Or think of it this way…..it raises your forefoot onto a higher plane.  Walk around on your heels with the ball of your foot off the ground.  Feel your anterior muscles challenge ? You might even feel the posterior compartment stretch load a little. And we know that when you put a stretch through a loaded muscle the golgi tendon organ fires to inhibit that muscle….. yup, right when you are about to need it to push off.  Pretty messed up huh ?

If you want to see some messed up mechanics buy your favorite enemy some earth shoes. Look for the knees to hyperextend backwards a little, look for a bouncy vertical gait, look for toe gripping/hammer toe development among other things.  They can be a sneaky vengeful gift. 

Shawn and Ivo….. rediscovering the old groovy trends and hoping everyone stops at zero-drop.  Otherwise watch out for our vengence …   “V” is for Vendetta ! 

Stretching out Plantar Fasciitis→

Neuromechanics Weekly: Look to the hammy’s???

“These findings show that while we always consider the tightness of the gastrocnemius/soleus complex and the subsequent restricted ankle motion from this equinus, we also need to consider the role of the hamstrings,” said Jonathan Labovitz, DPM, lead author and associate professor at Western University of Health Sciences, Pomona, CA.

this article from Lower Extremity Review, concludes “After controlling for covariates, participants (86 of 210 feet) with hamstring tightness were 8.7 times as likely to experience plantar fasciitis (p < .0001) as participants without hamstring tightness. Patients with a BMI >35 were 2.4 times as likely as those with a BMI <35 to have plantar fasciitis.”

The question is why?

They go on to say “ If you can’t get dorsiflexion at your talo-crural joint, this often drives dorsiflexion at other joints and that is going to cause collapse of the longitudinal arch of the foot, loading the plantar fascia with increased tensile stress.”

So, loss of ankle rocker leads to increased midfoot pronation, which loads the plantar fascia. That sounds pretty logical to us. We are sure you are thinking a loss of hip extension may do the same thing. Correct. Or you may say ” The calves may be tight so the medial gastroc can invert the rearfoot to correct for too much midfoot pronation and the foot can be supinated"…and you would be correct again.

So why are the tight hammys driving the bus? Or are they?

We remember the hams are a 2 joint muscle, and with the foot in a closed chain position (ie, on the ground); they flex the thigh on the lower leg and tilt the pelvis posteriorly (ie reduce the lordosis). They are FLEXORS which are active from late swing phase, just prior to heelstrike (initial contact) and a little nudge just prior to toe off (preswing) to help extend the thigh. 

The tricep surae are FLEXORS and are supposed to be active from loading response till almost pre swing, with a burst of activity at heel lift (terminal stance). 

So they take turns, and are not firing (normally) at the same time (or maybe have a small overlap). Going from heel strike to heel strike, the hammys fire 1st.

So IF the two are related, it could be a neurological sequencing issue. How often does that happen? The literature says (and there aren’t many studies) that you can change the order of recruitment of motor units ( the nerve and the muscle fibers it innervates), but not (usually) individual muscles. So probably not.

OK, how about plan B?

The hams and tricep surae are all flexors, correct? What is the innervation to the hamstrings and tricep surae? Hmm….Hamstrings, mostly tibial branch of the sciatic nerve, short head of biceps femoris is the common peroneal: L5-S2. How about the tricep surae? Tibial nerve, mostly S1-S2. I think I see a trend here. Common neurological overlap of FLEXOR muscles.

So are the hams driving the bus? Probably not, but neither are the gastroc/ soleus. The FLEXORS are driving the bus, and excitation of that common neuronal pool is probably causing the tightness

Ivo and Shawn….Uber footgeeks of the web. Dicing and slicing through the literature so you don’t have to.

Proof that women are not unstable at the time of menstruation.

On the subject of proprioception, here is something we found interesting while on a quest for another article. 1st, we had found an article in the NY Times blog, talking about training considerations of women during their monthly cycle.

They state: “There may, however, still be reasons a woman to consider her period when planning training. A study published this year by scientists at the University of Melbourne in Australia, for instance, found that when women’s estrogen levels were at their highest, around the time of ovulation, they landed subtly differently while hopping than at other times of the month. Their feet splayed, the arch collapsing just a little bit more than it did when their estrogen levels were lower. The women also seemed, to a small degree, wobblier. “We contend that the changes in foot biomechanics may be due to the effects of estrogen on soft tissue and/or the brain,” said Adam Leigh Bryant, a senior lecturer at the University of Melbourne and lead author of the study.”

This says, in a nutshell, that women are not unstable around the time of menstruation (dispelling many common myths to the contrary) but rather, they are unstable around the time of their ovulation (proprioceptively speaking, of course). Women on monophasic contraceptives showed less variability (greater stability) and therefore may be more less injury prone.

Of course we pulled the study (abstract below). We found it interesting that it may actually be a neurological/cortical phenomenon, rather that muscle estrogen receptor based. What is the advantage of less proprioceptive awareness with increased estrogen levels? Maybe (in a bit of a stretch), it was for propagation of the species. If the women can’t get away, then they are more likely to be caught (or less likely to be able to run…)

The Gait Guys….Sifting through the literature and sometimes poking a little fun at it.

Ivo and Shawn.

http://www.ncbi.nlm.nih.gov/pubmed/20857138

Eur J Appl Physiol. 2011 Feb;111(2):245-52. Epub 2010 Sep 21.

Estrogen-induced effects on the neuro-mechanics of hopping in humans.

Bryant AL, Crossley KM, Bartold S, Hohmann E, Clark RA.

Source

Centre for Health, Exercise and Sports Medicine, School of Physiotherapy, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, VIC, 3010, Australia. albryant@unimelb.edu.au

Abstract

Estrogen receptors in skeletal muscle suggest a tissue-based mechanism for influencing neuromuscular control. This has important physiological implications for both eumenorrheic women with fluctuating estrogen levels and those with constant and attenuated estrogen levels, i.e., women using the monophasic oral contraceptive pill (MOCP). This study examined the effects of endogenous plasma estrogen levels on leg stiffness (K (LEG)) and foot center of pressure (COP) during hopping. Nineteen females (Age = 28.0 ± 4.2 years, Ht = 1.67 ± 0.07 m, Mass = 61.6 ± 6.8 kg) who had been using the MOCP for at least 12 months together with 19 matched, female, non-MOCP users (Age = 31.9 ± 7.3 years, Ht = 1.63 ± 0.05 m, Mass = 62.5 ± 5.9 kg) participated. Non-MOCP users were tested at the time of lowest (menstruation) and highest (≈ ovulation) estrogen whilst MOCP users were tested at Day 1 and Day 14 of their cycle. At each test session, K (LEG) (N m(-1) kg(-1)) and foot COP path length (mm) and path velocity (mm s(-1)) were determined from ground reaction force data as participants hopped at 2.2 Hz on a force plate. Statistical analysis revealed no significant (p < 0.05) differences for K (LEG). In contrast, significantly higher COP path length (30%) and COP path velocity (25%) were identified at ≈ ovulation compared to menstruation in the non-MOCP users. Whilst there was no evidence of an estrogen-induced effect on K (LEG); significantly elevated estrogen at ≈ ovulation presumably increased extensibility of connective tissue and/or diminished neuromuscular control. Consistent lower limb dynamics of MOCP users demands less reliance on acutely modified neuromuscular control strategies during dynamic tasks and may explain the lower rate of lower limb musculoskeletal injuries in this population compared to non-MOCP users.

“There may, however, still be reasons a woman to consider her period when planning training. A study published this year by scientists at the University of Melbourne in Australia, for instance, found that when women’s estrogen levels were at their highest, around the time of ovulation, they landed subtly differently while hopping than at other times of the month. Their feet splayed, the arch collapsing just a little bit more than it did when their estrogen levels were lower. The women also seemed, to a small degree, wobblier. “We contend that the changes in foot biomechanics may be due to the effects of estrogen on soft tissue and/or the brain,” said Adam Leigh Bryant, a senior lecturer at the University of Melbourne and lead author of the study.”

Last week an article popped up on Men’s Health online. It was an article written by McDougall called A Wild Workout for the Real World. The article was about this chap Erwan LeCorre and the system of natural movement that he created.  Here is a sampling video. Enjoy. 

http://www.menshealth.com/fitness/fitness-survive-wild

The Confusion of Shoe Science (Part 5 of 5): Narrowing the Gap Between Science, Manufacturer, Retail and Consumer

This is an important series of lectures / debate.  This event occurred on December 6th, 2011 at The Running Event which we also lectured at.  The result of this series of talks, which we will post 2-5 sequentially daily here on our blog, was an underground heated dialogue between some of the speakers. 

We have come to greatly respect Blaise Dubois for his vast wealth of knowledge and his unbiased standpoint. Blaise is a physicial therapist with worldwide respect for his knowledge and experience.  Unlike some of the other speakers you will hear in the coming days, he had no vested interest other than sharing the facts and myths in this field.  This is why we have enjoyed our growing relationship with Blaise, because we too have no vested interest with any company other than the truth. 

Watch these videos and learn, and make your own conclusions.  But, if you are a runner or shoe store owner or staff, you need to watch these and open your mind and consider that what you are being told by your shoe vendors might not always be the truth.  Educate yourself, ask the hard questions of your shoe vendors and companies and make your own conclusions. 

Shawn and Ivo  ……. bringing this stuff to you so you do not have to find it on your own.

Thinking about throwing away those old running shoes? Think again. A recent study looking at plantar pressures in new vs old shoes reveled that newer shoes had higher perssures, assumedly due to increased stiffness of the shoe.

This definitely is a fly in the ointment about changing your shoes every 500 miles and supports a slow break in for any shoe.

Ivo and Shawn. Yes, we are shoe geeks…even on a Sunday

The Confusion of Shoe Science (Part 4 of 5): Narrowing the Gap Between Science, Manufacturer, Retail and Consumer

This is an important series of lectures / debate.  This event occurred on December 6th, 2011 at The Running Event which we also lectured at.  The result of this series of talks, which we will post 2-5 sequentially daily here on our blog, was an underground heated dialogue between some of the speakers. 

* Here is the problem. Shoes are not designed around the extreme foot types at either end of the Bell Curve.  They are designed for the foot in a normative range. Simon says here that we can manipulate the shoe to determine of the foot can pronate or supinate.  That is what shoes have been doing all along ! This is what the dual density is used for. This is what the crash zone is used for, etc etc.  This was a pretty commercialized closing by Simon, he spent alot of time talking about Asics. There was little “narrowing of the gap” for us.

Watch these videos and learn, and make your own conclusions.  But, if you are a runner or shoe store owner or staff, you need to watch these and open your mind and consider that what you are being told by your shoe vendors might not always be the truth.  Educate yourself, ask the hard questions of your shoe vendors and companies and make your own conclusions. 

Shawn and Ivo  ……. bringing this stuff to you so you do not have to find it on your own.