Hip flexors do not initiate hip flexon.

We have been saying it in writing and podcasts for years, the hip flexors are limb swing phase PERPETUATORS, not initiators of hip flexion.
It is the elastic response discussed below and the changing of the pelvis obliquity (from posterior positioning to anterior) via the abdominal wall acting on the pelvis-hip interval in conjunction with the stance phase hip musculature that drives hip flexion.
The next time you go after the psoas as a culprit in your meanderings for solutions, because that is what is all over the internet, think bigger, smarter, deeper.

"These experiments also showed that the trailing leg is brought forward during the swing phase without activity in the flexor muscles about the hip joint. This was verified by the absence of EMG activity in the iliacus muscle measured by intramuscular wire electrodes. Instead the strong ligaments restricting hip joint extension are stretched during the first half of the swing phase thereby storing elastic energy, which is released during the last half of the stance phase and accelerating the leg into the swing phase. This is considered an important energy conserving feature of human walking."

Dan Med J. 2014 Apr;61(4):B4823.
Contributions to the understanding of gait control.
Simonsen EB1.

#thegaitguys, #hip, #hipflexors, #pelvismechanics, #swingphase, #gait, #gaitanalysis, #gaitproblems

The hip flexors do not pull the leg forward during swing (mostly).

The hip flexors are not responsible for pulling/flexing the swing leg forward in gait or running. The psoas is a mere swing phase perpetuator, not an initiator.
For about 2 decades we have been saying in our lectures, posts and podcasts that it is the reduction of the obliquity of the pelvis during gait from various other tissues and biomechanical events that causes leg swing, meaning the trail leg is brought forward in swing largely by the abdominal muscle linkage to the pelvis (and other loaded tissues) that is responsible for forward swing of the leg. It is not the hip flexor group that does this hip flexion action. Thus it could be considered foolish to train the hip flexors to be the primary swing drivers. Here is another supporting piece of research.

"These experiments also showed that the trailing leg is brought forward during the swing phase without activity in the flexor muscles about the hip joint. This was verified by the absence of EMG activity in the iliacus muscle measured by intramuscular wire electrodes. Instead the strong ligaments restricting hip joint extension are stretched during the first half of the swing phase thereby storing elastic energy, which is released during the last half of the stance phase and accelerating the leg into the swing phase. This is considered an important energy conserving feature of human walking. "

Dan Med J. 2014 Apr;61(4):B4823.
Contributions to the understanding of gait control.
Simonsen EB1.

The hip flexors do not cause initial hip flexion.

The hip flexors are not responsible for pulling/flexing the swing leg forward in gait or running. The psoas is a mere swing phase perpetuator, not an initiator.
For about 2 decades we have been saying in our lectures, posts and podcasts that it is the reduction of the obliquity of the pelvis during gait from various other tissues and biomechanical events that causes leg swing, meaning the trail leg is brought forward in swing largely by the abdominal muscle linkage to the pelvis (and other loaded tissues) that is responsible for forward swing of the leg. It is not the hip flexor group that does this hip flexion action. Thus it could be considered foolish to train the hip flexors to be the primary swing drivers. Here is another supporting piece of research.

"These experiments also showed that the trailing leg is brought forward during the swing phase without activity in the flexor muscles about the hip joint. This was verified by the absence of EMG activity in the iliacus muscle measured by intramuscular wire electrodes. Instead the strong ligaments restricting hip joint extension are stretched during the first half of the swing phase thereby storing elastic energy, which is released during the last half of the stance phase and accelerating the leg into the swing phase. This is considered an important energy conserving feature of human walking. "

Dan Med J. 2014 Apr;61(4):B4823.
Contributions to the understanding of gait control.
Simonsen EB1.

https://www.ncbi.nlm.nih.gov/pubmed/24814597?fbclid=IwAR3yZQLb2Z0X1LZSVp2hOFLCt3wefsPt4iWEGveswn7-aGaou5OdDqmj4lA

So, what attaches to that hip capsule anyway....

I was trying to figure to which muscles attached to the labrum of the hip, as I see many folks where theres has gone south. I had always wondered if the iliopsoas attached, since many people with labral pathology have hip flexor dysfunction, where they use their psoas and iliacus as hip flexion initiators (or sometimes the rectus femoris, TFL and sartorius), instead of the abdominals. It turns out that NO MUSCLES attach to the labrum, but some attach to the capsule. 

Screen Shot 2018-03-26 at 9.18.31 AM.png

Have you noticed that many of the muscles on the list below (not the obturator internus) are internal rotators AND work during the 1st part of stance phase? Remember "glide and roll"? With internal rotation of the hip comes posterior translation of the femoral head. If these are dysfunctional, you may get capsular "pinching". Think about it with the next patient with hip joint pain from initial contact to midstance. 

"An updated knowledge of the intricate relationship of the pericapsular and capsular structures is essential in guiding our treatment of the hip. Following dissection the authors were able to discern that the iliocapsularis, indirect head of the rectus, conjoint tendon (of the psoas and iliacus),  obturator externus and gluteus minimus all have consistent capsular contributions whereas the piriformis did not have a capsular attachment."

 

Walters BL, Cooper JH, Rodriguez JA New findings in hip capsular anatomy: dimensions of capsular thickness and pericapsular contributions.
Arthroscopy. 2014 Oct;30(10):1235-45. doi: 10.1016/j.arthro.2014.05.012. Epub 2014 Jul 23.

Labral tears and altered motion during loading.

Screen Shot 2017-11-22 at 8.37.23 AM.png

"One might argue, that we sit the majority of our days with our femur and thus our femoral head pressed forward into the anterior and roof of the acetabulum. This becomes particularly suspect when in a conforming chair, such as a "bucket" seat in a car." -Shawn Allen



This article follows nicely with yesterday's post about hip joint control and anterior hip pain.

The premise behind this study referenced below was to determine if contact forces and electromyography (EMG) muscle amplitudes were altered during lunging activities in clients with painful labral tears compared to hose who are symptom free.
The unsurprising conclusions of this study ("contact forces and EMG muscle amplitudes are altered during the lunge for patients with symptomatic labral tears") are mostly predictable. But one should, we would hope, propose the chicken or the egg theory here.  Are these clients having pain because they are loading into the labral tear, or is the pain from poor joint stabilitation (and thus possible impaired normal mobility and motion) which incidentally lead to the labral loading and thus tear ?  We propose this one all the time. Why? Because we get a decent population of clients with typical "suspect" anterior hip labral pain and after rehabbing them, the pain resolves. So in these cases, was it a labral tear? Labral irritation? Or just a faulty loading response?
*However, we also get enough clients who present with an MRI in hand that confirms a labral tear, and we take them through the same process, and many of them also stabilize and have pain resolved. This then proposes the end question from them "So, was my pain from the labral tear at all? Or was it because had a poor stabilization capability, which lead to the tear/irritation?" 
And that folks, is the big question that has to be asked in all cases, and that is the unanswerable question.  But, should the process change regardless? If your client is going to head into surgery for the tear, should they not be fully rehabbed in the first place? And if the rehab works, is surgery even necessary ?  In the successful cases, we just stare openly at the client and smile, we let them answer the question. After all, they know the answer anyways.

Make no mistake. not everyone responds to our, or your, care. And, not every labral tear is incidental. Not every labral tear is undamaging to the femoral head and to the longer term health of the joint.  But, taking a few weeks and dedicating some good work into your client's skill, endurance, strength, power and loading responses often either give your client answers or prepare them for a great outcome post-operatively. 

In a nut shell, these can be tricky challenging cases. People sit and use the glutes as a cushion all day. We sit the majority of our days with our femur and thus our femoral head pressed forward into the anterior and roof of the acetabulum (depending on our sitting posture and chair choice).  They load similarly in their cars in challenged ways. They do not move well or often enough. They have weak glutes and abdominals and their ability to control the pelvis in safe loading is poor.  So many patients, and non-patients are on this bus, in fact, the majority of us are on it as well.  It feels like we are seeing more and more of these anterior hip problems, and we are not surprised as the average human moves less, is getting weaker and less durable and robust physically, and they sit more, and drive more.  This anterior hip pain clinical entity should really be no surprise to anyone anymore.
To be thorough, this study did "surface electromyography electrodes were placed over the gluteus medius, gluteus maximus, adductor longus, and rectus femoris muscles of the patients' involved limb and matched limb of asymptomatic controls."  This makes this an incomplete study with incomplete conclusions. As we said yesterday, without information on the mighty psoas and iliacus to name a few other big players, this study is somewhat suspect, but overall, we do not thing the results would come out too terribly different.

-Shawn and Ivo, the gait guys


Do Neuromuscular Alterations Exist for Patients With Acetabular Labral Tears During Function?
Arthroscopy. 2016 Jun;32(6):1045-52. doi: 10.1016/j.arthro.2016.03.016. Epub 2016 Apr 27.  Dwyer MK1, Lewis CL2, Hanmer AW3, McCarthy JC4.

https://www.ncbi.nlm.nih.gov/pubmed/27129378

More anterior hip pain dialogue.

Screen Shot 2017-11-20 at 9.55.19 PM.png

On a recent podcast we discussed complex hip problems, particularly hip stability and mobility issues lending themselves to anterior hip pain.
We have often mentioned ankle rocker being important in the discovery of hip pain, insufficient rocker can cause some impairments and abilities to get to ample hip extension function and range.
Here, this slightly older article mirrors a discussion we had on a recent podcast. We discussed the need for balance in the hip. More so, that focusing only on the glutes and hip extension can get one into trouble. One needs to also consider hip flexion skill, endurance and strength. The glutes and the hip flexors are a team to help maintain hip stability, mobility, and centration of the opposing joint surfaces during roll and glide motions. This is some of Shirley Sahrman's work, and others of course. When these component parts are not in harmony, and a loading force potentiates the femoral head towards the anterior labrum, it is the job of the glutes and hip flexors, to name two of the big players, to centrate that femoral head and keep it from impinging, and applying a forward load especially when this occurs during end motion loading into hip flexion and extension. I came across an article a while back that suggested these anterior directed movement risks are greater when the limb is loaded from being externally rotated, such as when making a strong power move or "cut" off the stance leg into the contralateral direction (we are looking for that source).
The bottom line is pretty simple, create sufficient stability to endure the loading challenge, but have enough strength and skill to still enable safe mobility. That being said, it is the diagnostics and the remedy that can be the tricky and challenging part of this game.

Anterior hip joint force increases with hip extension, decreased gluteal force, or decreased iliopsoas force. Lewis CL1, Sahrmann SA, Moran DW. J Biomech. 2007;40(16):3725-31. Epub 2007 Aug 17.

"Abnormal or excessive force on the anterior hip joint may cause anterior hip pain, subtle hip instability and a tear of the acetabular labrum.

We found that decreased force contribution from the gluteal muscles during hip extension and the iliopsoas muscle during hip flexion resulted in an increase in the anterior hip joint force. The anterior hip joint force was greater when the hip was in extension than when the hip was in flexion."

Gaining Anterior Length, Through Posterior Strength. A Lesson in Reciprocal Inhibition

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tumblr_oco89rcuI61qhko2so1_1280.png

Gaining Anterior Length, Through Posterior Strength and vice versa….A Lesson in Reciprocal Inhibition

I found a really cool article, quite by accident. I was leafing through an older copy of one of, if not my favorite Journals “Lower Extremity Review” and there it was. An article entitled “Athletes with hip flexor tightness have reduced gluteus maximus activation”. Wow, I thought! Now there is a great article on reciprocal inhibition! This reminded me of a piece we wrote some time ago

What is reciprocal inhibition, also called “reciprocal innervation” you ask? The concept, was 1st observed as early as 1626 by Rene Descartes though observed in the 19th century, was not fully understood and accepted until it earned a Nobel prize for its creditor, Sir Charles Sherrington, in 1932.

Simply put, when a muscle contracts, its antagonist is neurologically inhibited (see the diagram above) When your hip flexors contract, your hip extensors are inhibited. This holds true whether you actively contract the muscle or if the muscle is irritated in some manner, causing contraction. The reflex has to do with muscle spindles and Type I and Type II afferents which I have covered in an article I wrote some time ago.

We can (and often do) take advantage of this concept with treating the bellies of hip flexors (iliopsoas, tensor fascia lata, rectus femoris, iliacus, iliocapsularis) and extensors (gluteus maximus, posterior fibers of gluteus medius). This is especially important in folks with low back pain, as they often have increased psoas activity and cross sectional area, especially in the presence of degenerative changes.

There also appears to be a correlation between decreased hip extension and low back pain, with a difference of as little as 10 degrees being significant. Take the time to do a thorough history and exam and pay attention to hip extension and ankle dorsiflexion as they should be the same, with at least 10 degrees seeming to be the “clinical” minimum. Since the psoas should only fire at the end of terminal stance/preswing and into early swing, problems begin to arise when it fires for longer periods.

Can you see now how taking advantage of reciprocal inhibition can improve your outcomes? Even something as simple as taping the gluteus can have a positive effect! Try this today or this week in the clinic, not only with your patients hip flexors, but with all muscle groups, always thinking about agonist/antagonist relationships.




In the moment: Sports medicine  Jordana Bieze Foster: Athletes with hip flexor tightness have reduced gluteus maximus activation  Lower Extremity review Vol 6, Number 7 2014

https://tmblr.co/ZrRYjx1VG3KYy

Mills M, Frank B, Blackburn T, et al. Effect of limited hip flexor length on gluteal activation during an overhead squat in female soccer players. J Athl Train 2014;49(3 Suppl):S-83.

Ciuffreda KJ, Stark L.  Descartes’ law of reciprocal innervation. Am J Optom Physiol Opt. 1975 Oct;52(10):663-73.
Jacobson M Foundations of Neuroscience Springer Science and Business Media, Plenum Press, NY 1993 p 277

http://www.nobelprize.org/nobel_prizes/medicine/laureates/1932/sherrington-bio.html

https://thegaitguys.tumblr.com/post/9708399904/ah-yes-the-ia-and-type-ii-afferents-one-of-our

Arbanas J, Pavlovic I, Marijancic V, et al MRI features of the psoas major muscle in patients with low back pain. Eur Spine J. 2013 Sep;22(9):1965-71. doi: 10.1007/s00586-013-2749-x. Epub 2013 Mar 31.

Roach SM, San Juan JG, Suprak DN, Lyda M, Bies AJ, Boydston CR. Passive hip range of motion is reduced in active subjects with chronic low back pain compared to controls. Int J Sports Phys Ther. 2015 Feb;10(1):13-20. Erratum in: Int J Sports Phys Ther. 2015 Aug;10(4):572.

Paatelma M Karvonen E Heiskanen J Clinical perspective: how do clinical test results differentiate chronic and subacute low back pain patients from “non‐patients”? J Man Manip Ther. 2009;17(1):11‐19.[PMC free article] [PubMed]

Evans K Refshauge KM Adams R Aliprandi L Predictors of low back pain in young adult golfers: a preliminary study. Phys Ther Sports. 2005;6:122‐130.

Mellin G Correlations of hip mobility with degree of back pain and lumbar spinal mobility in chronic low‐back pain patients. Spine. June 1988;13(6):668‐670. [PubMed]

Lewis CL, Ferris DP. Walking with Increased Ankle Pushoff Decreases Hip Muscle Moments. Journal of biomechanics. 2008;41(10):2082-2089. doi:10.1016/j.jbiomech.2008.05.013.

Nodehi-Moghadam A, Taghipour M, Goghatin Alibazi R, Baharlouei H. The comparison of spinal curves and hip and ankle range of motions between old and young persons. Medical Journal of the Islamic Republic of Iran. 2014;28:74.

Daniel Moon , MD, MS; Alberto Esquenazi , MD Instrumented Gait Analysis: A Tool in the Treatment of Spastic Gait Dysfunction JBJS Reviews, 2016 Jun; 4 (6): e1. http://dx.doi.org/10.2106/JBJS.RVW.15.00076

Kilbreath SL, Perkins S, Crosbie J, McConnell J. Gluteal taping improves hip extension during stance phase of walking following stroke. Aust J Physiother. 2006;52(1):53-6.

Psoas, iliacus. . . .  hip flexors ?

How many times have you heard us say, “hip flexion in the swing phase of gait is not driven by the hip flexors. In swing phase, the psoas and iliacus complex is not a hip flexor initiator, it is a hip flexion perpetuator/” ?
More evidence … . .
“These experiments also showed that the trailing leg is brought forward during the swing phase without activity in the flexor muscles about the hip joint. This was verified by the absence of EMG activity in the iliacus muscle measured by intramuscular wire electrodes. Instead the strong ligaments restricting hip joint extension are stretched during the first half of the swing phase thereby storing elastic energy, which is released during the last half of the stance phase and accelerating the leg into the swing phase. This is considered an important energy conserving feature of human walking. ”

http://www.ncbi.nlm.nih.gov/pubmed/24814597

This Client went Phasic in their Gait. Do you know what that means ? We do, and so does McGill, Liebenson, Cook and many others.

Long ago on this blog we showed and discussed a video (link) that discussed Stu McGill's research of the human movements of Georges St-Pierre and David Loiseau. The basic tenets of that video were that the hips and shoulders are used for power production and that the spine-core are used for creating stiffness and stability for the ultimate power transmission through the limb.  He made it clear that if power is generated from the spine, it will suffer. 

Here on TGG we have long talked about phasic and antiphasic motions of the arms and shoulder-pelvic blocks during gait and locomotion/sport activity.  Many of our 1000+ blog writings and 80 podcasts have talked about spine pain and how spine pain clients reduce the antiphasic rotational (axial) nature of the shoulder girdle and pelvic girdle. In the video above, we see anything but antiphasic gait, to be clear, this is a classic representation of a phasic gait. This is pathologic gait, the frontal plane sway is exaggerated and necessary because there is no axial antiphasic motion.  There is essentially frozen arm and torso movements. This client has a long standing history of severe spine trauma and pain, their central pattern generators (CPG) had to make this motor pattern choice in an attempt to avoid pain and negotiate force streams across trauma zones. If you are curious and wish to go deeper down this rabbit hole, read the 30+ articles we have produced more specifically on arm swing and locomotor phasics, just click here.

In these types of cases, the client subconsciously makes the subcortial pattern choice (overrides the normal CPG) to rotate them as a solid unit to reduce spine rotation, axial loading and compression.  We could say that quite often spine pain disables the normal arm-leg pendulums via altering the shoulder-torso and hip-pelvis phasics and the CPG that dictates them. Normally, the spine and core must present sufficient amounts of recruited stiffness, yet mobility where necessary, to enable the locomotive power and velocity generated by movements of the shoulders and hips. These are the two main portals of limb movement off of the spine/core.  These principles holds true in gait and sport. For and interesting example, in human gait the psoas is not entirely a hip flexor initiator when it comes to leg swing, it is a huge hip flexion perpetuator. The initial hip flexion in human gait comes from derotating the obliqued pelvis, via abdominal contraction, on a stiff and stable spine.  Once the pelvis rotation is initiated, the femur can further pendulum forward (via contraction of the psoas and other muscles) on the forward accelerated pelvis in the hip joint proper creating an energy efficient movement (the towel flick/whip effect). This premise holds true in gait, running, kicking etc.  This is a solid principle of effective and efficient human locomotion. This principle also holds true for a punch or throwing an object, the stable torso/spine provides a stable anchor upon which to accelerate the arm in order to create a high velocity limb movement with power.  But here is where we get annoyed much of the time.  (Soap box Tangent coming up) How often do you read articles about tight ITBand, tight psoas, tight piriformis and the like ?  As a “diagnosis” these are weak and they are the “go to diagnosis or cause” of the unseasoned clinician, trainer, coach, therapist. If we all are to be really good at our job, we must go beyond what we see in someone’s gait (since it is the compensation) and go beyond the CNS neuroprotective strategy of tightness/shortness when there is weakness or motor pattern failure.  This does not mean that you cannot, or should not, incorporate restoration methods and principles to restore length-tension relationships in your client, it means you have to resolve ALL of the problems, including the aberrant CPG they have set up as a protective default to avoid injury or further injury. 

In the case above, returning the discussion to arm and leg swing, one must understand clearly that faulty arm swing patterns and lack of antiphasic torso and pelvis oscillation is a product of surgery,  trauma and more so, pain. The client is avoiding the antiphasic presentation (hence, he is phasic) for a reason and coaching more arm swing would be just about the dumbest intervention, so don’t be “that guy”. We know this is an altered motor pattern choice, not a new fixed set point. We know this because on clinical examination the range is available, we know because we examined for it, it is just not being used.  In an example of this same principle, in this case talking hip ranges of motion, McGill discusses the same in his paper*:

“Despite the large increases in passive hip ROM, there was no evidence of increased hip ROM used during functional movement testing. Similarly, the only significant change in lumbar motion was a reduction in lumbar rotation during the active hip extension maneuver (p < 0.05). These results indicate that changes in passive ROM or core endurance do not automatically transfer to changes in functional movement patterns. This implies that training and rehabilitation programs may benefit from an additional focus on grooving new motor patterns if newfound movement range is to be used.”

Think about that next time you stretch, or are stretched by someone. As we have said before, just because you increase someone’s range of motion, does not mean they will be able to incorporate that range of motion into a movement pattern, or compensation pattern for that matter. It is only ¼ of the equation: Range of Motion,  Skill (or proprioception),  Endurance (or the proportion of slow twitch muscle) and Strength (the proportion of fast twitch muscle). There is our S.E.S. mnemonic again.

In this video case, lack of NORMAL antiphasic spinal motion (torso and pelvis moving opposite one another) is noted. Without the obliqued pelvis the swing and stance phases will be impaired. The psoas may have to become more of a hip flexor initiator, AS WELL AS the perpetuator of limb swing, because there is no pelvic obliquity from the antiphasic principles to drive it from. And so, when you see this fella in your office with bilateral tight psoas/hip flexor complex and tight quadriceps mechanisms with resultant impaired glutes and hip extension, please do not begin lengthening them as your point of initiation.  They are that way because he has gone phasic in his gait.  Change the motor patterns that drive this as best as possible, restore any weaknesses that are contributory to, or initiate, these motor patterns and then, if needed, encourage some progressive new length-tension in these muscle groups as improved motor patterning evolve to allow for it.  You are likely going to have to go back and reteach and restore primitive and postural sensory motor windows in these cases, so be patient, be kind, be wise. Oh, and do not forget that with impaired hip function, there will most likely be impaired ankle rocker,  you are going to need a wide angled lens to see, capture and remedy this lads problems.

On another note, can you imagine what this client’s video gait analysis would show and interpret ? Let alone the diagnostics and recommendations that could come from it?  What about the appearance of their foot pressures across a dynamic foot pressure plate (or God forbid a static one !), surely what is seen at the foot is this client’s problem (not !) And forgive those poor fools who recommend a shoe for this client based off of just those mediums alone.  Without a complete hands-on clinical examination to correlate gait cycle observances, any recommendations for this case will be traumatic on many levels. 

Today’s bottom line……. read, learn, think, stay hungry, be wise.

Shawn and Ivo, The Gait Guys

* Improvements in hip flexibility do not transfer to mobility in functional movement patterns.  Moreside, Janice: McGill, Stuart

link: http://journals.lww.com/nsca-jscr/Fulltext/2013/10000/Improvements_in_Hip_Flexibility_Do_Not_Transfer_to.1.aspx

Podcast 46: Georges St. Pierre, Regenokine & Compensation Patterns,

Podcast 46 is live !
Topics: Diffuse Axonal Shear in the nervous system, the new procedure Regenokine, the neurologic status of UFC fighter Georges St. Pierre, PCP thearpy, the new generation of slow running children, posture, compensation patterns, pre-race Tylenol effects/dangers, tibialis posterior tendonitis, shoe selection and so much more !  If you have not listened to one of our podcasts, this one will surely give you a good taste of what you are missing !

A. Link to our server:

http://thegaitguys.libsyn.com/podcast-46-slow-kids-regenokine-compensation-patterns-monty-python

B. iTunes link:

https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138

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

http://store.payloadz.com/results/results.aspx?m=80204

D. other web based Gait Guys lectures:

www.onlinece.com   type in Dr. Waerlop or Dr. Allen,  ”Biomechanics”

________________________________________

* Today’s show notes:

Neuroscience Pieces:
1.  Future of computing 
 
2. We have been talking about body part replacements like bionics etc……but this could be the stone in the road to this progress
 

REGENOKINE: THE UNPROVEN TREATMENT THAT PROFESSIONAL ATHLETES ARE FLYING TO GERMANY FOR

5. Gait Factoid, posture matters
This week you did another post on running faster and about  "lifting the head to engage extensors"……  here was an article in the news on posture
- can you give the listeners a neat neuro tidbit on posture and the brain ?
6. Ivo: What is your take on leaving obvious problems and compensations alone or fixing them ?      
7 . National Shoe Fit Program
8 . Tylenol Boosts Performance in Hot Conditions
 9. from a blog reader:
Hello Gait Guys,
What would you look to do with a 20 year-old competitive 5k runner (me) with chronic posterior tibialis problems?
- a short background: surgery two years ago on left talo-navicular joint osteochondral defect, since then mileage has been extremely limited (now it begins to fatigue painfully on 30 minute runs). 
Both sides affected, or sometimes one or the other. Arch of right foot got so painful last summer I was on crutches and could not walk/stand without supportive shoes. Currently the left side is most troubling and I can see no pattern!
Many thanks for the fantastic blog
Joy
10. Facebook reader:
  • I thought I’d go the experts on this one. I just took a myofacsical release class and the instructor said the most efficient running gait is by using your psoas. So, forward lean until you are about to fall forward and then contract psoas to lift the leg just enough to catch up with the body. He said this is how all the Kenyans run… makes sense kind of.. but???

11. Disclaimer:

“Georges St-Pierre, MMA Limb Power & Spinal Stiffness” … Gait Guys style.

Here at ‘The Gait Guys’ we have been going at this teaching, writing and filming process for many years now. On our blog we have written over 1100 articles, our YouTube Channel and Facebook page continue to grow  and our podcasts continue to be heard presently in 85 countries.  We have a long way to go to get our message heard but we trust that our message is clean and clear and based on science and fact. Today we share with you a video of one of our personal professors from our undergraduate studies in human kinetics back in Canada in the late 1980’s, the world renowned Dr. Stuart McGill. In this video he speaks some of these clear honest facts about the spine, movement, joint loading and the sport of MMA (Mixed Martial Arts).  Watch the video, but be sure to read on here, where we bring things full circle for our readers.

We have been on a long academic quest when it comes to learning about different types of movement and we are willing to go to great lengths to humble ourselves to further this mission. Many of our long time readers are aware by now that at the end of 2012 Dr. Allen completed 3 years of private study of smooth and Latin dance to better understand the intricacies of core strength, foot work and complex limb coordination amongst other things. If it was good enough for Bruce Lee (1958 Hong Kong Cha Cha Champion) it is good enough for us ! Just like Tim Ferris, one of the modern day bio and brain hackers, who also took up the Tango to put to the test some facts about brain learning, we too are in it to learn and take things to the highest level possible. 

   Many of you by now know that I have moved my learning from dance into a different kind of study in human movement. I have now committed my brain and body to learning Brazilian Jiu-Jitsu under the instruction of World renowned World Champion Professor Carlos Lemos Jr. You can read about them here, Gracie Barra Downers Grove

There are many similarities between dance and jiu-jitsu (believe it, it is true) and we have completed a comparative article which we will post on The Gait Guys blog in the coming days to validate these thoughts on the human frame in both sports.  However, this is not the point of this brief blog article today, our point was to share the teachings of one of our mentors Dr. McGill.  In this video, showing the research of human movements of Georges St-Pierre and David Loiseau, Dr. McGill discusses the basic tenet that the hips and shoulders are used for power production and that the spine and core are used for creating stiffness and stability for the ultimate power transmission through the limb.  He makes it clear that if power is generated from the spine, it will suffer.  As gait experts, you should never forget this principle, if the spine and lumbopelvic interval is not strong/stiff and stable enough, the limbs can over power them and thus your gait, your running, your sport, could be causing you pain as the forces are poorly managed as they attempt to traverse the spine. 
McGill implies that martial artists find themselves near the top of the heap when it comes to power, strength and speed with an ability to contract muscles with great velocity but also the ability to relax the muscles with a terrific rate of speed. It is this ability to effectively and timely contract and relax that gives a martial artist the advantage.
However, these advantages can only be realized with a special ability to create spinal stiffness effectively, efficiently and with speed and coordination. These are huge advantages when in combat. We all hear about the importance of the core but these are the tenants that are key when referring to the core. And as McGill states, in martial artists who kick and punch, there must be an ability to create an initial pulse of energy, premised off of a stiff and stable spine. This is then followed by a relaxation of some of the limb muscles to ensure maximal velocity (a kinetic chain whip effect, like snapping/flicking a towel) and then followed by a sudden and timely re-stiffening of the spine, core and limb muscles to ensure that maximal force is transmitted to the opponent.
The spine and core must present sufficient amounts of recruited stiffness, yet mobility where necessary, to enable the power and velocity of the movements of the shoulders (punching) and hips (kicking) which are the two main portals of limb movement off of the spine/core.  These principles holds true in gait as well. For example, in human gait the psoas is not a hip flexor initiator when it comes to leg swing, it is a hip flexor perpetuator. The initial hip flexion in human gait comes from derotating the obliqued pelvis, via abdominal contraction, on a stiff and stable spine.  Once the pelvis rotation is initiated, the femur can further pendulum forward (via contraction of the psoas and other muscles) on the accelerated pelvis in the hip joint proper creating an energy efficient movement (again, the towel flick/whip effect). So, this premise holds true in gait, in an effective martial arts kick or even in a soccer kick. This is a solid principle of effective and efficient human locomotion. This principle also holds true for a punch or throwing an object, the stable torso/spine provides a stable anchor upon which to accelerate the arm in order to create a high velocity limb movement with power.

Watch the attached video of Georges St-Pierre, David Loiseau and Dr. Stuart McGill. These are foundational principles of movement in many sports and the martial artists seem to have it down pretty darn well.  These are the things we study and write about here at The Gait Guys. We are more than just gait.
Dr. Shawn Allen 
Dr. Ivo Waerlop 
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The Psoas Muscle in a Runner: An Endurance Savy Muscle ?

 We received a question yesterday from a doctor. We felt it was worthy of sharing. Here it is, followed by our response.

Doctor:  I do have a question about one of my athletes in particular.  He is a fairly good (All-State in IL) high school track distance runner that has some left sided femoral acetabular impingement.  He gets some capsular hip pain that also will ‘tighten up’ his low back during speed endurance/threshold running only.  Moderate and easy distance runs cause no problem and neither do track/speed workouts.  Only during speed endurance does he have issues.  Upon evaluation after these sessions he does seem to have some low back QL tightness, but joint mobility is fairly good in his lumbar spine.  He does show marked hypertonicity through his left hip joint.  I’m not quite sure the mechanism here- why he would only flare up with speed endurance running- any insights?
Thanks a bunch and I look forward to hearing from you!

The Gait Guys response:

 You state “only during speed endurance” does he have issues. We will assume you mean a long, hard anaerobic workout, which would tax type II b fibers. You also mention he has hypertonicity through his hip joint.  Since the psoas crosses this joint it should be considered in sprinting and long, hard endurance activities, especially if the patient is flexor dominant. The psoas major muscle is composed of type I, IIA and IIX muscle fibers. It has a predominance of type IIA muscle fibers. The fiber type composition of the psoas major muscle was different between levels of its origin starting from the first lumbar to the fourth lumbar vertebra. The psoas major muscle has dynamic and postural functions, which supports the fact that it is the main flexor of the hip joint (dynamic function) and stabilizer of the lumbar spine, sacroiliac and hip joints (postural function). The cranial part of the psoas major muscle has a primarily postural role, whereas the caudal part of the muscle has a dynamic role. This is all very much supported in this journal article here (link) (http://www.ncbi.nlm.nih.gov/pubmed/19930517) and making it work in an endurance capacity would certainly cause issues. Flexor dominance is a common scenario we see clinically, due to insufficient extensor activity (and decreased vestibulo and reticulo spinal drive to extensors) and increased cortico spinal drive (to the flexors, including the iliopsoas). This would fuel the “bail out” (lack of stability) of the lower abs. The anterior tippage of the pelvis would drive the femur posteriorly, binding the joint (the opposite of an anterior femoral glide).

Video footage and some pix of your athlete would provide more insight for us to help.

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