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

Written by Dr. Shawn Allen


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 10 years our dear gait brethren, is has been a great ride. Shawn and Ivo
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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” (unfamiliar 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 (happy April Fools day) , 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 or before you blame the dog for any "something wicked this way comes" gaseous event. 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, 2 juveniles at times, when the world needs us the most.

Shawn and Ivo, remaining here, for the duration.

disclaimer: we cannot be responsible for injuries that might be sustained by improper off-gassing events. Keep your work area a no smoking or vaping zone please when off-gasing. We also do not recommend attempts at performing Blue Angels, this is a potentially dangerous activity and could cause great bodily harm (seriously). :)

Keep your eyes up and your toes up...,And it doesn’t hurt to use your abs

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While out cross country skiing after a few inches of fresh fallen snow it dawned on me, especially when going uphill on my cross-country skis, lifting your toes up definitely pushes the head of the first metatarsal down and helps you to gain more purchase with the scales on the bottom of the skis. It also helps to press the center portion of the camber of the ski downward so that you can get better traction. Thinking about this further, lifting your toes up also helps you to engage your glutes to a greater degree.

Try this: stand comfortably with your knees slightly flexed. Lift up your toes leaving the balls of your feet on the ground. Do you feel the first metatarsal head going down and making better contact with the ground? Can you feel your foot tripod between the head of the first metatarsal, head of the fifth metatarsal and the calcaneus? Now let your toes go down. Squeeze your glute max muscles. You should still be able to fart so don’t squeeze the sphincter. You can palpate these muscles to see if you’re actually getting to them. You can do this by placing your hands on top of your hips with your fingers calling around forward like when your mom used to put her hands on her hips and yell at you. Now relax with your toes up again leaving the balls of your feet on the ground. Now engage your glutes. See how much easier it is?

Now stand with your feet flat on the ground and put your hands on your abs, specifically your external obliques. Now raise your right leg. Do you feel your external oblique engage? Now, lift your toes up leaving the balls of your feet on the ground. Now lift your leg. Do you feel how much more your abs engage?

Little tricks of the trade. That’s why you listen here and why your patients/clients come to see you. Now go out and do it!

Dr. Ivo, one of The Gait Guys

#gaitanalysis, #crosscountryskiing, #skiing, hallux, #engage, #abs

Abdominal Activity and Gait   We came across this cool study today, after a well educated patient asked about abdominal activity during gait.    Here is the bottom line:  low level activity in the rectus abdominis and external oblique throughout the gait cycle, more concentrated activity of the internal oblique at initial contact/loading response (heel strike).    This makes sense, since the external oblique occupies more real estate and has a larger cross sectional area; it most likely has a role in stabilization both in rotational  like emoticon  planes as well as the saggital plane (Z). Perhaps the action of the internal oblique at initial contact is to assist in external rotation of the pelvis on the stance phase leg, as the the opposite leg goes into swing?  “Cluster analysis identified two patterns of activity for the internal oblique, external oblique and rectus abdominis muscles. In the lumbar erector spinae, three patterns of activity were observed. In most instances, the patterns observed for each muscle differed in the magnitude of the activation levels. In rectus abdominis and external oblique muscles, the majority of subjects had low levels of activity (<5.0% of a maximum voluntary contraction) that were relatively constant throughout the stride cycle. In the internal oblique and the erector spinae muscles, more distinct bursts of activity were observed, most often close to foot-strike. The different algorithms used for the cluster analysis yielded similar results and a discriminant function analysis provided further evidence to support the patterns observed”  Clin Biomech (Bristol, Avon). 2002 Mar;17(3):177-84. Abdominal and erector spinae muscle activity during gait: the use of cluster analysis to identify patterns of activity. White SG1, McNair PJ.

Abdominal Activity and Gait

We came across this cool study today, after a well educated patient asked about abdominal activity during gait.

Here is the bottom line:
low level activity in the rectus abdominis and external oblique throughout the gait cycle, more concentrated activity of the internal oblique at initial contact/loading response (heel strike).

This makes sense, since the external oblique occupies more real estate and has a larger cross sectional area; it most likely has a role in stabilization both in rotational like emoticon planes as well as the saggital plane (Z). Perhaps the action of the internal oblique at initial contact is to assist in external rotation of the pelvis on the stance phase leg, as the the opposite leg goes into swing?

“Cluster analysis identified two patterns of activity for the internal oblique, external oblique and rectus abdominis muscles. In the lumbar erector spinae, three patterns of activity were observed. In most instances, the patterns observed for each muscle differed in the magnitude of the activation levels. In rectus abdominis and external oblique muscles, the majority of subjects had low levels of activity (<5.0% of a maximum voluntary contraction) that were relatively constant throughout the stride cycle. In the internal oblique and the erector spinae muscles, more distinct bursts of activity were observed, most often close to foot-strike. The different algorithms used for the cluster analysis yielded similar results and a discriminant function analysis provided further evidence to support the patterns observed”

Clin Biomech (Bristol, Avon). 2002 Mar;17(3):177-84.
Abdominal and erector spinae muscle activity during gait: the use of cluster analysis to identify patterns of activity.
White SG1, McNair PJ.

Subtle clues often provide the answers.  
 We like yoga as much as anyone else. We saw this picture on the latest cover and couldn&rsquo;t resist making a few comments on this pose. 
 Yoga has many benefits. Our understanding is that in addition to the cognitive and spiritual effects of yoga, is that it helps to build your core. 
  At first look you may say that this woman has a few issues: 
  she has a right pelvic shift and a left body lean 
 She has slight head rotation to the right and a slight left head tilt 
 you may have noticed that she appears to have more tone in the musculature on the right side of her face than on the left.   Just look at the nasolabial fold as well as the corner of her mouth any area of wrinkling underneath her left orbit. 
  You may have also noticed the subtle flexion and lack of external rotation of the right hip. 
   You may go on and think that she has a week right gluteus medius as well as an overactive quadratus lumborum on the left-hand side which may be causing the pelvic shift. The head tilt may be in compensation for the right side gluteus medius weakness and the subtle rotation may be an attempt to engage a tonic neck response. ( a tonic neck response is  ipsilateral extension of the upper and lower extremity to the side of head rotation with contralateral flexion of the same counterparts. 
   You may have also noticed  that the toes of the right foot are not dorsiflexed and that her hair appears to be flowing on the right side, and this is not the case at all, but rather she is either standing on a sloped surface or on the downward phase of a jump. According to the magazine it is the latter.  If you caught this at first then  congratulations:   you are sharper than most . If not remember to always look for subtle clues. 
  Like Sir Topham Hat says in Thomas the Train: &ldquo;  You didn&rsquo;t get the whole story. What really happened is what really matters. 
  So why the mild facial ptosis on the left side? She could have had an old Bells palsy, or other form of facial paresis. Note that mostly the lower portions of the (left) face are affected (ie, below the eye). We remember that the upper portions of the face receive bilateral innervation but lower portions of the face unilateral innervation, from the contra lateral facial motor nucleus; this is why it could be a mild upper motor neuron lesion (micro infact, lack of cortical afferent input) and not an lower motor neuron lesion (like Bells Palsy). Why is this germane? Or is it not?  
 Stand in front of a mirror. Jump up in the air trying to assume the same pose as this woman does and what do you see.  Make sure that you jump up from both legs and then bring one leg over and your hands in front of you in the &quot;praying position&rdquo;. You may want to have a friend take a snapshot of you performing this. You will notice that you have contralateral head rotation,  a pelvic hike on the side opposite the leg that&rsquo;s extended and a head tilt to the side that is flexed.  You are attempting to stabilize your core as you&rsquo;re going up and coming down. 
 What we are witnessing is a normal neurological phenomena.  This gal merely seems to have some limited external rotation of her left hip. Now perform the same maneuver again but this time don&rsquo;t externally rotate your leg as far as this woman does and what do you see. You should&rsquo;ve seen an increase in the aforementioned body postures. 
 Subtle clues are often the key. Keep your eyes and ears open.  
  The Gait Guys. Helping the subtle to become everyday for you, with each and every post.

Subtle clues often provide the answers.

We like yoga as much as anyone else. We saw this picture on the latest cover and couldn’t resist making a few comments on this pose.

Yoga has many benefits. Our understanding is that in addition to the cognitive and spiritual effects of yoga, is that it helps to build your core.

 At first look you may say that this woman has a few issues:

  • she has a right pelvic shift and a left body lean
  • She has slight head rotation to the right and a slight left head tilt
  • you may have noticed that she appears to have more tone in the musculature on the right side of her face than on the left.   Just look at the nasolabial fold as well as the corner of her mouth any area of wrinkling underneath her left orbit.
  •  You may have also noticed the subtle flexion and lack of external rotation of the right hip.

 You may go on and think that she has a week right gluteus medius as well as an overactive quadratus lumborum on the left-hand side which may be causing the pelvic shift. The head tilt may be in compensation for the right side gluteus medius weakness and the subtle rotation may be an attempt to engage a tonic neck response. ( a tonic neck response is  ipsilateral extension of the upper and lower extremity to the side of head rotation with contralateral flexion of the same counterparts.

 You may have also noticed that the toes of the right foot are not dorsiflexed and that her hair appears to be flowing on the right side, and this is not the case at all, but rather she is either standing on a sloped surface or on the downward phase of a jump. According to the magazine it is the latter.  If you caught this at first then congratulations: you are sharper than most. If not remember to always look for subtle clues.

 Like Sir Topham Hat says in Thomas the Train: “  You didn’t get the whole story. What really happened is what really matters.

So why the mild facial ptosis on the left side? She could have had an old Bells palsy, or other form of facial paresis. Note that mostly the lower portions of the (left) face are affected (ie, below the eye). We remember that the upper portions of the face receive bilateral innervation but lower portions of the face unilateral innervation, from the contra lateral facial motor nucleus; this is why it could be a mild upper motor neuron lesion (micro infact, lack of cortical afferent input) and not an lower motor neuron lesion (like Bells Palsy). Why is this germane? Or is it not?

Stand in front of a mirror. Jump up in the air trying to assume the same pose as this woman does and what do you see.  Make sure that you jump up from both legs and then bring one leg over and your hands in front of you in the "praying position”. You may want to have a friend take a snapshot of you performing this. You will notice that you have contralateral head rotation,  a pelvic hike on the side opposite the leg that’s extended and a head tilt to the side that is flexed.  You are attempting to stabilize your core as you’re going up and coming down.

What we are witnessing is a normal neurological phenomena.  This gal merely seems to have some limited external rotation of her left hip. Now perform the same maneuver again but this time don’t externally rotate your leg as far as this woman does and what do you see. You should’ve seen an increase in the aforementioned body postures.

Subtle clues are often the key. Keep your eyes and ears open. 

The Gait Guys. Helping the subtle to become everyday for you, with each and every post.

A blast from the past. Here’s one of our favorite posts, just in case you missed us a few years ago…

More Gait Guy Gait Gaffs: What it would look like if “The Flash”, ran with heel strike ? click here. Note the excellent anterior compartment use (nice ankle dorsiflexion and toe extension at terminal swing/ pre-impact) but heavy, nasty, heel strike. What is interesting here is that he has adopted a nice forward lean (ala. natural or chi running style) but when combining this with a heel strike gait you end up with an anterior pelvic tilt (which begins inhibition of the lower abdominals) and you then have to begin the power through phase in early-mid stance phase with the hamstrings. You need tremendous lower abdominal strength, and hamstring length and strength to run this way (go ahead, get up and try it running through your office ! let out a great “Yaulp” from the ensuing hamstring pull (ala Robin Willliams in Dead Poets Society) when you find out your abdominals are not strong enough to lean that far forward and still heel strike, without enough hamstring length (on second thought, just trust  us……although i know now we have challenged some of you). This is a medical disclaimer, dont do it !