The smell of napalm in the morning: Your gait and trouser coughs, a clinical entity no one talks about.

This is our very last gait guys blog post. Yes, all good things come to an end, even this trusted blog.
But, keeping in good faith, we will finish on a strong note ……. One of gardenia and lavender.  Thanks for the last 5 years gait brethren, is has been a great ride.  Shawn and Ivo
The technical title of this blog post should have been, “The reactive influence of non-normopressure bowel distention and spontaneous high vapor dissipation on bipedal locomotion.”  but no one but true gait nerds would have read it had we stuck with this pubmed-type title. Yes, we are talking about farts and gait here today folks, buckle up.

One biomechanical principle we will link to this entity of “off-gassing“ is that excessive or sustained ankle plantarflexion could inhibit dorsiflexion and certainly, at the very least, works against it. We have talked about this often here on the blog and how the lack of ample ankle dorsiflexion can impair many of the biomechanical events higher up into the human frame. So, how can someone’s bowel gas translate into gait problems ?

Think about this …  to squeeze out a right “cheek sneak” (fart) with optimal crowd pleasing pitch and peak vibrato, some elevation and relaxation of the lower and middle gluteus maximus divisions (coccygeal and sacral) seems imperative to optimally control off-gassing . Seemingly, to do this, a significant degree of right ankle plantarflexion may be necessary to lift the right hemipelvis driving a subsequent intentional clockwise pelvic distortion assisting in the relaxation of these gluteal divisions.  This consciously driven right side of the body “lift” via the right ankle plantarflexion can also be met and assisted via ipsitlateral abdominal and contralateral gluteus medius contraction to further enable the optimal right hemipelvis elevation. Go ahead, stand up and mimic the posture and note these biomechanical pieces. Recall our mantra, 

“when the foot is on the ground, the glutes are in charge, when the foot is in the air, the abdominals are in charge”.  

These coordinated motor patterns might be considered dual/multi tasking. This honed series of biomechanical events is one often perfected in frat houses and basement gaming rooms. But make no mistake, there is a biomechanical danger lurking here if this becomes a habitual compensation pattern, one common in large volume legume consumers (beware vegans). Habituation of this motor task, or demonstrating poor technique over time can render right quadratus lumborum shortening and weak lower abdominals rendering an anterior pelvic tilt. This tilt may lead to gluteal inhibition/weakness (because it is difficult to contract the gluteals in an anterior pelvic tilt, go ahead stand up again and try it) which over time can impair stance phase gait mechanics. However, relating to the off-gassing, this physical posturing might optimize low frequency gluteal vibrations that can optimize vibrato during gas dissipation if pressurization is in fact optimal for an “audible”.  It is important to note that conscious variable control of the tonus of the muscular anal sphincter complex plays a big part in the pitch and vibrato. There is always a drawback it seems, it does truly come down to motor control it seems, doesn’t it always ?

This is not to say that avoiding “audibles” through holding “one” in doesn’t have consequences. The exotic gas (nitrogen, carbon dioxide, hydrogen, methane, oxygen) induced gut distention that could only make your collage roommate proud can inhibit the abdominal wall and thus the lower thoracic canister and disable normal breathing mechanics. This could be a serious complication to the coupled events of respiration and thoracic mobility. So, holding that big one in for your friends rather than engaging the compensatory Trendeleburg-type off-gassing posture as described above is also fraught with problems. We know that functional disconnection of the thoracic canister from the pelvic core can disrupt the normal anti-phasic mechanics of the contralateral upper and lower limbs as well as possibly impair the normal spinal cord mediated central pattern generators.

Farts…..Call them what you want, those ear pleasing, nose hair curling, trouser coughs that only a teenage boy can truly relish and recognize as a function of boyhood success.  All joking aside, they truly should be your biggest concern in your gait analysis evaluation, bar none. Ask your patients about their bowels and off-gassing, it should be part of your clinical history intake. Maybe even consider taking out the discomfort of open dialogue, and put it on your intake forms. We found that a stick figure diagram in a good biomechanical squat posture with a mushroom cloud formation hanging overhead eases dialogue tension about this sensitive topic. We even give the young children crayons to they can color the cloud. What fun !

Dare us to write a part two on this topic. “Blue Angels” (unfamilar with this clinical phenomenon? look it up). Go ahead, dare us for a part 2. 

By now, if you haven’t realized that The Gait Guys just punked you, then you likely haven’t had your cup of morning coffee. Yes, we have no clue what we were talking about on this blog post, well, ok maybe, after all we do have that y-chromosome. Yes, we are NOT ending the blog either 🙂 

Are you now considering us juvenile ? Ok maybe we are a little, but don’t deny it, you thought about some unique and honest body biomechanics for a moment here and it is these mental gymnastics that will take your creative thinking about gait to the next level. If you are upset, so be it. There will be no apologies here in this growing PC world. Off-gassing is a human thing, we all do it. We have been writing serious stuff daily for 5 years here on The Gait Guys. It was time for us to write something a little lighter.  We can only hope that you will think of us and the complexities of the gait cycle the next time you sneak one out while having dinner at the in-laws.  Try not to giggle when you do, but for certain, think about your body mechanics when you do, we can’t be responsible for off-gassing injuries. Think of us.

Shawn and Ivo, remaining here, for the duration.

disclaimer: we cannot be responsible for injuries that might be sustained by improper off-gassing events. We also do not recommend attempts at performing Blue Angels, this is a potentially dangerous activity and could cause great bodily harm (seriously). 🙂

Abs on the UP, Glutes on the DOWN

I had the opportunity to go on my 1st mountain bike ride of the season last Sunday morning. Yes, I am aware it is JUNE, but the snow has finally melted (we had over 7 FEET at arapahoe Basin in May) and you need to understand that I am usually a runner). In the cool morning 44 degree air I was reminded of the importance of my gluteal muscles (rather than just my quads) while climbing a technical hill which was clearly pushing my aerobic capacity. We have the opportunity to perform many bike fits in the office and treat many cycling ailments. We also train and retraing pedal stroke and one of our mantras (in addition to skill, endurance and strength) is “Glutes on the downstroke; Abs on the upstroke”. Meaning use your glutes to extend the hip from 12 to 6 o’clock and use your abs to initiate the upstroke. Quadricep (on the downtstroke) and hamstring dominance (on the upstroke) is something we see often and this mantra often proves useful in the “retraining process”.

I have been a fan of Ed Burkes work (“Serious Cycling” and “Competitive Cycling”) for years and have read (and lectured about) these books many times. In my effort to find a basis in the literature for my mantra, I ran across a paper (1) that seemed to substantiate, at least in part, the mantra. It is a small study looked at elite athletes that explores changes that occur in muscle recruitment as the body fatigues after a sub maximal exercise session.

Their conclusion “The large increases in activity for gluteus maximus and biceps femoris, which are in accordance with the increase in force production during the propulsive phase, could be considered as instinctive coordination strategies that compensate for potential fatigue and loss of force of the knee extensors (i.e., vastus lateralis and vastus medialis) by a higher moment of the hip extensors.”

This makes sense, although may be contradicted by this study (2), which showed LESS gluteal activity at higher mechanical efficiency, with increased tricep surae activity. They conclude “These findings imply that cycling at 55%-60% V˙O(2max) will maximize the rider’s exposure to high efficient muscle coordination and kinematics.”  Although this study looks at mechanical efficiency and the 1st lloks at muscle activity.

Being seated on a bike and having your torso, as well as hips flexed is not the most mechanically efficient posture for driving the glutes, but clinical observation seems to dictate that the less quad and hamstring dominant people are on the down and up stroke respectively, then the more pain free they are. This does not always equte to being the fastest, but it does equate to fewer injuries showing up in the office.

  1. Dorel S1, Drouet JM, Couturier A, Champoux Y, Hug F. Changes of pedaling technique and muscle coordination during an exhaustive exercise. Med Sci Sports Exerc. 2009 Jun;41(6):1277-86. doi: 10.1249/MSS.0b013e31819825f8.
  2. Blake OM1, Champoux Y, Wakeling JM.  Muscle coordination patterns for efficient cycling. Med Sci Sports Exerc. 2012 May;44(5):926-38. doi: 10.1249/MSS.0b013e3182404d4b.

Hip muscles and postural control related to ankle function.

Hip exercises boost postural control in individuals with ankle instability

-“Four weeks of hip external rotator and abductor strengthening significantly improves postural control in patients with functional ankle instability (FAI) and may be useful for preventing recurrent instability, according to research from Indiana University in Bloom­ington.”

Nothing new here, at least not here on The Gait Guys blog. We have been talking about these kinds of issues for a long time. We  have long discussed the necessary control of the glutes (and their anchoring abdominals) to eccentrically control the loading response during the stance phase of gait, we especially like to discuss the control of the rate of internal rotation (read: eccentric ability of external rotators as a component) of the leg with the glutes. It is why we think it is so important to eccentrically test the glutes and the core stabilizers (all of them !) when the client is table assessed because it is a huge window for us as to what is happening when there is ground interface. Sure one is open chain and the other is closed, but function is necessary in both. 
What this article is again, like others, telling us is that the ability to stack the joints (knee over foot, hip over knee, level stable pelvis over hip) improves postural control, especially when there is a risky environment of ankle functional or anatomical instability. 
And yes, we are talking Cross over gait and frontal plane challenges and faulty patterns here.  Failure to stack the joints usually leads to cross over gait challenges (type in “cross over or cross over gait into our blog SEARCH box). Remember though, you must selectively strengthen the weak muscles and weak motor patterns, if you are not specific you can easily strengthen the neuro-protective tight muscles and their patterns because they have been the only available patterns to your client. If you are not careful, you will help them strategize and compensate deeper, which in itself can lead to injury.  This is a paramount rehab principle, merely activating what appears weak does not mean you are carrying them over to a functional pattern. Just because you can show a change on the table doesn’t mean it carries over to the ground and sport or training. 
Shawn and Ivo, the gait guys

Podcast 78: Step Width Gait, Training Asymmetries & more

Show sponsors:

A. Link to our server:

Direct Download:

B. iTunes link:

C. Gait Guys online /download store (National Shoe Fit Certification and more !) :

D. other web based Gait Guys lectures:   type in Dr. Waerlop or Dr. Allen,  ”Biomechanics”


Today’s Show notes:

24-year-old woman missing entire cerebellum exemplifies the amazing power of brain plasticity

Brain scans reveal ‘gray matter’ differences in media multitaskers

Who are we: Ivo talk a bit about yourself and your educational history and what is your website ?
Shawn… the same
and……lets keep each interesting but to just a few minutes
Effect of step width manipulation on tibial stress during running
Does Limited Internal Femoral Rotation Increase Peak Anterior Cruciate Ligament Strain During a Simulated Pivot Landing?
Quadriceps Muscle Function After Exercise in Men and Women With a History of Anterior Cruciate Ligament Reconstruction

The Abductor Heel Twist: Look carefully, it is here in this video.

This should be a simple “piece it together” video case study for you all by this point. This young lad came into our office with left insertional achilles pain of two weeks duration after starting some middle distance running.

What do you see here ? It is evident on both the right and the left, but it is a little more obvious on the left and can be seen on the left when he is walking back toward the camera as well.  You should see rearfoot eversion, it is excessive, and a small rearfoot adductor twist. Meaning, the heel pivots medially towards the midline of his body.  Some sources (Michaud) call this an Abductory Twist, but the reference there is typically the forefoot.  Regardless, to help our patients, we sometimes refer to this is “cigarette butt” foot. It is like stepping on a lit cigarette to put it out via twisting/grinding it into the ground. 

So, now that you can see this, what causes it? 

The answer is broad but in this case he had a loss of ankle dorsiflexion range.  The ankle mortise clearly did not have enough of ankle rocker range during midstance so as that limitation was met, the heel raised up prematurely during the moments when the opposite leg is in full swing imparting an external rotation on the stance limb (hence the external foot spin (adducting heel/abducting foot……depending on your visual reference)). There is a bit more to it than that, but that will suffice for now because it is not the central focus of our lesson today.

What can cause this ? As we said, a broad range of things:

  • hallux limitus
  • flexion contracture of the knee (swelling, pain, joint replacement etc)
  • short calf-achilles complex
  • weak tib anterior and extensor toe muscles
  • Foot Baller’s ankle
  • limited/impaired hip extension
  • weak glute (minimizing hip extension range)
  • sway back (lower crossed syndrome-type biomechanics)
  • short quadriceps (similarly impairing hip extension)
  • flip flop excessive use (or any other motor strategy that imparts more flexor compartment dominance (read: calf-achilles, FDL)
  • excessive pronation
  • impaired foot tripod mechanics
  • etc

The point is that anything impairing TIMELY (the key word is timely) forward sagittal gait mechanics can, and very likely will, impair ankle rocker.  Even the wrong shoe choice can do this (ie. someone who suddenly drops from a 12 mm heel ramped shoe into a 0-4mm ramped heel shoe and who thus may not have earned the length of the calf-achilles complex as of yet).

The abductor-adductor twist phenomenon is not a normal visual gait observation. It is a softly seen, but screaming loud, pathologic gait motor pattern that must be recognized.  But, more importantly, the source of the problem must be found, confirmed and resolved.  In this fella’s case, he has some weakness of the tib anterior and extensor toe muscles that has lead to compensatory tightness of the calf complex. There was no impairment of the glutes or hip extension, as this was just 2 weeks old or so, but if left unaddressed much longer the CNS would have likely begun to dump out of hip extension and gluteal function to protect……another compensation pattern. Remember, ankle rocker and hip extension have a close eye on each other during gait.

Clinical pearl for the true gait geeks…… if you see someone with a vertically bouncy forefoot-type gait (you know, those people that bounce up and down the hallway at work or school) you can usually suspect impaired ankle rocker and if you look closely, you will usually see a quick abductor-adductor twist.

Shawn and Ivo

the gait guys

Unilateral heightened toe extensor tone.

What do we have here ? Well, it is obvious. The left foot is showing increased short extensor tone (EDB: extensor digitorum brevis) and heightened long flexor tone (FDL: flexor digitorum longus). This is the classic pairing for hammer toe development.  We also know from this post (link) and from this post (link) that this presentation is closely related with lumbrical weakness and distal fat pad migration.

So, at an assessment took we like to play games. Mental games to be precise. When we see something like this we immediately begin the mental gyrations of “what could have caused this, and what could this in turn be causing”. Remember, what you see is often not the problem, rather your clients compensation around the problem.  In this case, what goes through your mind ?  Without deep thought, our knee jerk thoughts are:

  • possible loss of ankle rocker dorsiflexion (the increased EDB tone can be recruited to help drive more ankle dorsiflexion indirectly)
  • plantar intrinsic weakness ?
  • flip flops or slip on shoes where the heel is riding up and down inside the shoe/sloppy fit ?  (initiating a gripping response from the FDL)
  • weak tib anterior (recruiting EDB to help)
  • weak peroneus tertius (recruiting EDB again)
  • Ankle /foot instability (more FDL gripping will help gain ground purchase)
  • lateral ankle instablity (same thing, more gripping)
  • Weak gastrosoleus (since the FDL is a posterior compartment neighbor it can kick into high gear and help with posterior comparment function, we have a whole video case based around this issue, check this out ! )
  • premature departure off of the good side leg, and thus an abrupt loading response onto this affected side can challenge the frontal plane of the body and thus require more grip response at the foot level.
  • how about simple weakness of the lumbricals or FDB , the short flexors. The long flexors will have to make up for it and present like this.  
  • the list goes on and on … .

These are just some quick cursory thoughts, and by NO means a complete exhaustive list.  Just some quick thoughts.

But what about hip function ?  if ankle rocker is blocked in terminal stance and the FDL fire like this what will that do to hip extension ? Well, heel rise will be premature because of the limitation and thus hip extension will be abbreviated. Thus glute function will be impaired to a degree.  This can become a viscous cycle, each feeding off of each other.

This diagnostic stuff is a tricky and difficult game. If you think you can diagnose or fix a problem from just changing what you see you are mistaken, unless you like driving compensation patterns and future injuries into your clients.   There must be a hands on examination and assessment with an intact educated brain attached to the process.

Just some mental gymnastics for you today.  

Shawn and Ivo

the gait guys

Muscle Activation Concerns

We are concerned about some things that are showing up in our clinics lately. Strange injury patterns we have not seen before. We know you are all very busy, because you are the best what you do, but we hope that by sharing these 2 articles with you we can all further raise this team of practitioners, coaches, physical therapists, trainers, pilates and yoga instructors, surgeons etc and work even more effectively as a team.  
This issue is about muscle activation or facilitation.
As you are all learning, this game is more than just turning muscles on, and there are risks to turning something on when the central nervous system has decided it is not safe to turn something on. We are all treating people who are slouched over all day either as students or at desk jobs and thus everyone (seeing as they are all dropped into hip, knee and cervical, thoracic and lumbar spine flexion) will have some degree of inhibited glutes (and thus reciprocal neuro-protective hip flexor tightness) that appear to need activated when the truth is that they need more central extension facillitation. Activating the glutes when there is a central flexion inhibition driver overrides the nervous system’s protective inhibition response. Hence the near-epidemic of hamstring and hip flexor/groin/labrum tear problems we are seeing !   There are logical reasons why something is not activated. Sometimes it is a 
1. muscle skill pattern (large diameter nerve, all muscle fiber diameters), 
2. sometimes it is an endurance problem (large diameter nerve, small muscle fiber diameter),
3.  sometimes it is a strength problem (largest diameter nerve, largest diameter muscle fibers). 
Knowing a problem is driven by 2 or 3 will tell the practitioner that activation will not solve the problem and that activation can force a compensation pattern that can lead to a future injury. Also, sometimes it has nothing to do with the muscles motor nerve activity, it may in fact be about the reciprocal inhibitory neurosensory input (see our post on reciprocal inhibition here). 
Hence we wanted to share 2 articles we wrote. These articles were spurred by the magnified influx in the last year of injuries that appear compensatory, meaning they seem to have occurred because alternative compensatory motor patterns were encouraged where there appear to be clear signs that they should not have been encouraged.  In other words, sorry to say this, people with a weaker understanding of how and why the nervous system works are using muscular activation as a tool when it is the wrong tool. When you are pounding a nail, using a screwdriver won’t get you good results, and might get you the wrong results. But, if all you have is a screwdriver … . .
The blog posts are below. We strongly believe that many of these injuries we are seeing are not necessary. We always ask ourselves when a person who we have been working on says to us “honest doc, I really did not do anything, I was just running comfortably and the hamstring grabbed at me for no apparent reason.”  These stories always make us look in wards and ask “is this injury my fault ?” “Did this occur because I was activating the wrong muscles and wrong patterns thus forcing them into a less worth protective pattern because I thought I knew better than their nervous system did ?” When we want to learn we judge ourselves and our actions  harshly, for we know we make mistakes and we know we are still students. We know that if it appears simple, it might be a good time to step back and think it through a little more. 
Don’t just be an muscle “activator”, be a thinker who occasionally activates when it is appropriate.  The nervous system knows better than you do, accept this and try to figure out why it is shutting things down.
Shawn and Ivo

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