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). 🙂

The mighty Quadratus Plantae! Here is a video short on this awesomely important muscles function, testing and exercise. Enjoy!

Pod #93: Ankle Rocker, Sacroiliac Joint symmetry , Landing mechanics

Ankle Rocker, Sacroiliac Joint symmetry , Landing mechanics, Gait Tech, Gray Cook theories, movement and music and so much more !

A. Link to our server:

Direct Download:


-Other Gait Guys stuff
B. iTunes link:
C. Gait Guys online /download store (National Shoe Fit Certification & more !)
D. other web based Gait Guys lectures:
Monthly lectures at : type in Dr. Waerlop or Dr. Allen, ”Biomechanics”

-Our Book: Pedographs and Gait Analysis and Clinical Case Studies
Electronic copies available here:


-Barnes and Noble / Nook Reader:

-Hardcopy available from our publisher:

Show notes:

-Landing mechanics

-Shock absorbing landing loads
J Athl Train. 2015 Jun 11. [Epub ahead of print]
Weight-Bearing Dorsiflexion Range of Motion and Landing Biomechanics in Individuals With Chronic Ankle Instability. Hoch MC1, Farwell KE1, Gaven SL2, Weinhandl JT1.

Trying to reteach your client’s CNS new sensory-motor patterns so they can move better ?
New connections and pathways are fragile and only through repetition and practice and focused attention can those connections be established enough to become habitual or default behaviors.
Neuroscience for Leadership: Harnessing the Brain Gain Advantage (The Neuroscience of Business). Tara Swart

-Does variability in muscle activity reflect a preferred way of moving or just reflect what they’ve always done?

-Context-dependent changes in motor control and kinematics during locomotion: modulation and decoupling. Foster and Higham

-gait technology problems 😕

-Dance video discussed, Alvin Ailey Dance Company

-SI joint anatomy/rehab piece:
more rehab strategies here:

-a few minutes on Gray Cook quotes. pick a few we can talk about (pic attached)

movement patterns talk:

Just because it looks good, doesn’t mean that it is.

We have all had patients with seemingly negative knee x rays and pain, only to develop arthritic changes at a later date. Find and treat the cause!

“Our analysis found that incident radiographic knee osteoarthritis is preceded by prodromal symptoms lasting at least 2-3 years. This has potential implications for understanding phasic development and progression of osteoarthritis and for early recognition and management.”

Case R, Thomas E, Clarke E, Peat G. Prodromal symptoms in knee osteoarthritis: a nested case-control study using data from the Osteoarthritis Initiative. Osteoarthritis Cartilage 2015 Apr 2. [Epub ahead of print]

picture from:…/chronic-pain-understanding-the-roots…/

“Due to the shape of the condyles and the menisci, and the location of ligaments of and muscles acting on the knee, the joint rotation axis is located medially in the knee joint. This also in part explains why the lateral condyle and meniscus are more mobile. Maximum extension of the knee is caused by these factors and the “screw home” mechanism of the cruciate ligaments. The popliteal muscle is connected with the lateral meniscus and the caput fibulae: it locks the knee joint in and unlocks the knee joint out of its maximum extension. Moreover, it plays an important role for proprioception in the knee joint and is known to cause posterolateral knee pain.


Forefoot valgus: A fixed structural defect in which the plantar aspect of the forefoot is everted on the frontal plane relative to the plantar aspect of the rearfoot; the calcaneum is vertical, the mid tarsal joints are locked and fully pronated

Want to know more? Join us Wednesday evening: 5 PST, 6 MST, 7 CST, 8 EST for Biomechanics 309: Focus on the forefoot on

McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

Fore foot types: Differences between forefoot varus and forefoot supinatus.

Certainly this can be a contraversial topic. Perhaps this will help clear up some questions.

Supination of the forefoot that develops with adult acquired flatfoot is defined as forefoot supinatus. This deformity is an acquired soft tissue adaptation in which the forefoot is inverted on the rearfoot. Forefoot supinatus is a reducible deformity. Forefoot supinatus can mimic, and often be mistaken for, a forefoot varus. A forefoot varus differs from forefoot supinatus in that a forefoot varus is a congenital osseous deformity that induces subtalar joint pronation, whereas forefoot supinatus is acquired and develops because of subtalar joint pronation (1).

A Forefoot Varus induces STJ pronation whereas a Forefoot Supinatus is created because of STJ pronation (2).

As the foot experiences increased subtalar joint (STJ) pronation moments during weightbearing activities (as in forefoot supinatus) , the medial metatarsal rays will be subjected to increased dorsiflexion moments and the lateral metatarsal rays will be subjected to decreased dorsiflexion moments. Over time, this increase in STJ pronation moments will tend to cause a lengthening of the plantar ligaments and medial fibers of the central component of the plantar aponeurosis and a shortening of the dorsal ligaments in the medial longitudinal arch. As a result, the influence of increased STJ pronation moments occurring over time during weightbearing activities will tend to cause the following (3):

1. An increase in inverted forefoot deformity.
2. A decrease in everted forefoot deformity.
3. A change in everted forefoot deformity to either a perpendicular forefoot to rearfoot relationship or to an inverted forefoot deformity.

More on the forefoot tomorrow evening on Biomechanics 309. Join us!

1. Clin Podiatr Med Surg. 2014 Jul;31(3):405-13. doi: 10.1016/j.cpm.2014.03.009. Forefoot supinatus. Evans EL1, Catanzariti AR2.