Arm swing and Gait Stability

"When discussing the effects of arm swing on gait stability, it is
necessary to start with a definition of gait stability. In steady-state gait, infinitesimally small perturbations are ever present, and the system’s response to such perturbations may be called local stability. When gait is externally perturbed, global stability can be assessed by quantifying the response to such a perturbation. Following Bruijn et al. [12], in human gait, this response may be divided into two phases: an initial phase, which is dependent upon both the steady state of the system (as it was before the perturbation) and the system’s intrinsic mechanical properties (e.g. inertia, stiffness), and a second, reactive phase (‘recovery’), which is mainly dependent on active control and reflexes." - P. Meyns et al. / Gait & Posture 38 (2013) 555–562

*The how and why of arm swing during human walking
Pieter Meyns a,1 , Sjoerd M. Bruijn a,b,1, Jacques Duysens a,c,

Planks for 10 seconds ?

Take this new "McGill'ism" with a grain of salt and in the context it may have been given, ie. for general core strength for the average person.
For what we do however, we do not agree this is a rule to follow. In our clients, when working on functional stability deficits, adhering to a 10 second rule won't often make sense to resolve the issues of planar skill, endurance or strength deficits.

http://www.businessinsider.com/sports-scientist-says-there-is-no-point-in-holding-plank-for-long-time-2018-3

Nose picking and your running form problems.

Nose picking and running form

I use an example, with the appropriate clients, that humidifying one's home in the dry winter to try and break a nose picking behavior that was borne of resultant dry mucous linings doesn't necessarily mean one will break the 3 month habit of nose picking.
Furthermore, just because you decide to humidify the house doesn't mean your brain is going to halt the nose picking that has become a subconscious habit. Similarly, consciously asking someone to turn in their externally rotated foot (increased foot progression angle) or turn in the entire limb during gait, which might have been the result of frontal plane weakness of the ankle from an ankle sprain, isn't going to fix a problem that has now become an adaptive compensatory behavior at the hip. One has to get to the root of the problem, the unaddressed ankle sprain and neurologic behavioral adaptive patterns, at both the ankle and the hip. Plus, it just might get you to stop picking your beak, although, some sources now say that a good digested booger might be good for your immune system (probably a piece written by a happy confident picker).
- a Monday morning Dr. Allen rant

Got Short leg?

Ahhhh. They get it!

Our favorite quote from this article " Understanding limb-length compensation
We encourage you to pay as much attention to any abnormal compensation pattern as you do to the LLD itself. It is well documented that abnormal biomechanics, such as you would find in a compensatory pattern, can result in vibratory forces and microtrauma along the closed kinetic chain (Figure 1). The spinal facet; hip, knee, ankle and foot joints; and their associated muscles may suffer repetitive microtrauma resulting in sprain, strain, or degenerative joint disease. By addressing compensatory neuro-musculoskeletal function, you may be able to assist the patient with a cascade of dysfunction through the musculoskeletal system.

We also encourage you to make use of gait assessment technology to quantify, document, and monitor patients’ progress. Application of reproducible, documented metrics is essential to communicate effectively within a multidisciplinary system that is committed to practicing evidence-based medicine."

http://lermagazine.com/cover_story/assessing-limb-length-discrepenacy

Ruminations on a child with Calcaneal Valgus

Have a young patient with severe calcaneal valgus? Here are some of our thoughts...

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. 

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.

4 ways to fix your running stride ? ummmm

Just too simple and cooked down an article for us.
eh, maybe 2 of these have some value. But we wouldn't head to the bank on them. We have plenty of pro runners who have a decent hallux rigidus and compensate surprisingly well. But, if it ain't broken, and causing other things to become broken, leave it alone. Consider making anatomic anomalies more durable when you cannot fix or change them. As for premature heel rise, "stretch the calf", that is all they were willing to come up with? Our readers know to go a little deeper (anterior compartment assessement, hip extension assessment etc). Zero mention of hip as a cause. He merely touched on the hip drop one in our post yesterday, but that is a goliath of a topic. Read with a jaundiced eye.
 

4 Ways to Fix Your Running Stride

A seasoned biomechanics expert offers his top insights on running-form danger signs

https://www.outsideonline.com/2293286/four-ways-fix-your-running-stride?utm_medium=social&utm_source=facebook&utm_campaign=onsiteshare

Plantar flexion matters, too. Don't get stuck only on ankle rocker/dorsiflexion.

Plantarflexion matters, too.
"one must gain posterior length through anterior strength, lose the strength, lose the length."

We always seem to be harping on ankle rocker and ankle dorsiflexion. But, ankle plantarflexion matters just as much, but in different ways. This study went off of plantarflexion contracture, but we see shortness in the gastroc and soleus all the time, it seems in fact to go with loss of anterior compartment weakness, which is in essence, a functional (if not more truly restricted) loss of ankle rocker. Typically these 2 beasts are both in the same shopping bag. It is why we like to say, "one must gain posterior length through anterior strength, lose the strength, lose the length." This is not to say that shortness, tightness or contracture are the same thing, in fact they are on completely different spectrums. But, losing "posterior mechanism" length (short, tight or contracture), for whatever reason will do many potentially bad things to one's gait cycle and biomechanics. There are too many here of those to name, but, a functionally longer leg, tendency towards knee extension, knee flexion accomodation, early heel rise, abrupt departure from the limb and and abruptly onto the contralateral side, increased forefoot loading problems, toe clenching, loss of hip extension, impaired hip extension, increased quadriceps tone (and thus possible increased PF joint compression), changes in step and stride length and step width are just the start of some of the things your brain needs to start juggling.

The above are some of the thoughts immediately triggered by reading this abstract , , ,

Clinical Biomechanics. Volume 29, Issue 4, April 2014, Pages 423-428
The impact of simulated ankle plantarflexion contracture on the knee joint during stance phase of gait: A within-subject study
Joan Leung, Richard Smith, Lisa Anne Harvey. Anne M. Moseley, JosephChapparo

Do you really understand a runner's hips ? Coaching out things you don't like to see doesn't make it a "fix".

"All the technique in the world doesn't compensate for the inability to notice"- Elliott Erwitt

Excerpt: "So if your remedy for this runner is to just add a "loaded Farmer's carry" on the opposite side, your thinking is right if it is a strength issue in the contralateral hip. IF it is an endurance issue you need a lighter weight and more unilateral Farmer's carrying. If it is a weight management issue, you may be poking the bear. Maybe it is a multitude of issues. "

There are loads of folks taking 'this' seminar series, or 'that' one, striving for 'this' certification or 'that' one. This is trememdous, it keeps the professions moving. But, all the technique in the world doesn't mean a thing if one cannot see, feel, test, or most importantly comprehend and express a client's primary flaw(s) in mobility and stability. The right tools in unskilled hands are useless, and arguably present risks for clients.

We have said this many times, too many for certain, that what you see in your client is not their problem, it is their means of moving within their present abilities and dysfunctions for whatever reason (ie. lack of skill, endurance, strength, power etc). We have also said that a mere exercise, test or screen doesn't take one to the end zone either, they are also a mere piece of the bigger puzzle. An exercise or test also may only tell you what they are capable (or incapable of), but not why their pain or challenges exist. Thus, taking a failed test, and making it your client's new exercise does not necessarily create an environment for a remedy, it can in fact create one of a more durable compensation. And that is ok, if that is what you are searching for, if that is the emergency bandaid you need before the marathon in 3 weeks, but if you are swinging for the remedy, you may have to trudge the extra yard.

Last week we taught about some basic hip principles during our online class. Take this runner photo for example, below is a basic principle you must glean from the photo. It is a principle based off of remedial joint biomechanics, as incomplete as it is, the thought process should be one you consider and certainly comprehend. In this photo, this runner appears to have insufficient stance phase hip abductor (HAM) strength or endurance. This is in part notable because of the adduction of the contralateral thigh (this is a faulty swing leg pendulum mechanical event, and will undoubtedly lead to a cross over gait and a plethora of other gait problems).

Here is one question that should always come to mind:
Are the stance phase hip abductors strong enough, or have enough endurance, to offset the body mass ? (see the line diagrams). Look at the diagram formula, and let us discuss.
If the pelvis is to remain level (mostly), the D1 and D2 lever arms do not change, the D1 lever arm is always shorter and thus the HAM (Hip abductor muscle strength) will always have to be a large number to offset the BQ (body weight). If BW gets too large, there will be no HAM large enough to offset BW and the pelvis will dip, as in this runner's photo. So, it can be a weight issue, a HAM strength issue, a HAM endurance issue or both. Someone is going to win, and someone is going to pay if the system is not balances and durable. We see this in the failed frontal plane running mechanics all the time in our offices, this is a plague in runners. It is a major source of the spine, pelvis, hip knee and foot issues we see in runners. To fix these clients, you have to understand their mechanics. The latest rehab toy that you bought at after a jazzy seminar pitch doesn't replace the requisite knowledge one needs to have to understand a clients problem. Screens won't get you all the way, tests and pattern assessments won't get you all the way either. You have to do your learning part, the knowledge must precede your interventions.

So if your remedy for this runner is to just add a "loaded Farmer's carry" on the opposite side, your thinking is right if it is a strength issue in the contralateral hip. IF it is an endurance issue you need a lighter weight and more unilateral Farmer's carrying. If it is a weight management issue, you may be poking the bear. Maybe it is a multitude of issues. But, if it is a mobility issue, adding your Farmer's carry doesn't guarantee you will get the client to the promised land, and if it is a stability issue, perhaps you get close.
* This article does not chase down deeper evaluation concepts such as narrow step width, femoral torsions, tibial torsions, swing phase gait mechanic failures, sagittal plane (A-P pelvis control) or rotational plane challenges to the system (failure to control limb rotation at the hip or at the foot) just to name a few. This article ONLY looked at the frontal plane concept, so hopefully one is gleaning how complex these biomechanics are. Hopefully one is gleaning at this point that this is not a spot corrective exercise prescription game, "here is the visually disturbing pattern, here is the exercise to eclipse that pattern". There does need to be some brain engagement in the process to do this right, and this means education and hands on clinical examination.

The Farmer's carry is a beautiful exercise when placed correctly in a client's regimen. There are many who say we take this game too completely, too precisely, too far, that we make this too complex and if one listens to us that one might develop stage fright to execute any intervention. Well, sorry, but we stand our ground. This is not an easy game. Too many people come to see us after intermediate regimens of training and lifting develop problems, problems that were not present at the initiation of their attempts to better they body. If one is being honest with themselves, they should ask themselves, could this have been prevented? Was the work prescribed part of the eventual deliverance? Injuries occur when loads exceed durability, skill, endurance, strength, power etc. One could make the case that if the prescriptions are correct, if the progressions are correct, that injury should be a rare thing. But injuries are not uncommon and those of us who are prescribing corrective exercises and workout regimens have to take self accountability if we are being honest with ourselves.
Don't get us wrong, we are just as much a pupil on this bus as anyone else, we make mistakes all the time. But everyday we force ourselves to pause, consider, double check, reassess, to make sure that the developing patterns are sound, strong, durable and progressive, and ready for more. And when we get it wrong, we reexamine, and try again. It is all one can do.

Stir about your own clinical world with a jaundiced, questioning eye, and you should do just fine. And if you cannot get it right, get it close, prescribe something safe and watch and test for clues of developing problems in the near future. This we all call . . . . learning/ practice.

"All the technique in the world doesn't compensate for the inability to notice"- Elliott Erwitt

Shawn Allen, one of the gait guys

The "most elusive" man in North America

76 runner. Elusive, lives in a bus, running everyday, creating his own trails, calling the shots every minute of his day. Inspiring message.

https://youtu.be/QcJoW9Lwzs0

Rewind: Walking gait in a pencil skirt

Gait Pathomechanics: Walking in a Pencil Skirt.

We wrote this piece 5 years ago. We are updating it with a new disasterous video. Speed ahead to the 30 second mark to get to the good stuff. The Gait stuff.
No longer can there be adequate use of the obliquity of the pelvis and thus abdominals or contralateral leg swing to initiate supination and toe off and . . .

blog link: https://www.thegaitguys.com/…/gait-pathomechanics-walking-i…

https://www.youtube.com/watch?v=LSVzlRouRk4

The glutes are in fact great internal hip rotators, too. Open your mind.

The glutes as an internal rotator ? Yes, to understand squats and lunges and deep hip flexion activities one needs to understand that the glutes , which we typically perceive as hip extensors and external rotators, can also assist in internal rotation. Which, we explain in this 2 years old rewind blog post.
We discussed this at length in our online teleseminar last night. Join us for this and other deep gait and biomechanics topics every 3rd Wednesday of the month !

I recently got a message from a colleague questioning as to how in the world, that when the hip is in flexion, the glutes and piriformis become internal rotators.  This is again another example of lack of functional anatomy knowledge.  It took me awhile to find a picture to help explain this, but I finally found one reasonable to do so. Many readers who are stuck on this concept are just too stuck on the anatomy as presented in the image to the right, neutral stance-like.  This article today will be all about internal and external moment arms, here, this lecture will help a little, it is on glute medius internal moment arms in stance phase however, so there is little carry over but it will at least get you understanding moment arms more clearly. 

We tend to just think of the glute max as a hip stabilizer and extensor, for the most part. It also decelerates flexion in terminal swing.  The glute medius is mostly thought of as a lateral hip stabilizer and abductor, either of the femur (open chain) or of the pelvis in stance position (closed chain), meaning zero degrees or neutral plus or minus the trivial degrees of engaged hip flexion and extension used in normal gait.

No one I know consciously trains the glutes as an internal rotator, but there are many actions where we need this function, such as in crawling and many high functioning activities such as martial arts grappling and kicking for example. Gymnasts should also know that the glutes are powerful internal hip rotators.  If you are doing quadruped crawling work you also need to know this as your client approaches 90 degrees of hip flexion. No one ever seems to check this critical gluteal function, at least I see it missed all the time from my referring doctors and therapists for unresolving hip pain cases. Patients with hip pain, anterior, lateral or posterior, with lack of internal hip rotation need the glutes checked just as much as the other known internal hip rotators we all seem to know (though some still do not understand how powerful the vastus lateralis is as an internal rotator, but again, those are folks who just have not spend the time in a mental 3D space looking at functional anatomy. I live mentally in that 3D space all day long when working with patients, you should too.) Let me be more clear, the anterior bundle, the iliac bundle of the glute max, is an internal rotator in flexion, the sacral and coccyxgeal divisions are not, they are external hip rotators in flexion. The gluteus medius and minimus are internal hip rotators closing in on 90 degrees hip flexion.  Hence, you must be able to tease out these divisions in your muscle testing, one cannot just test the glutes as external rotators or extensors, you are doing a really sloppy job if that is all you are doing. Nor should someone just train the glutes as hip stabilizers, external hip rotators and extensors (which is probably 90% of the trainers and coaches out there I might assume?). IF one knows the origin and insertions (see the blue and green arrows) and moves those points towards each other in a fashion of concentric contraction (purple arrows) one should be able to easily see that this will orient the femur to spin into internal rotation in the acetabulum (follow the arc of the black arrows). The same goes for eccentric contractions, it is the same game.  If you are doing DNS and crawling work, you should know this stuff cold gang. When you close chain the hip in sitting, or are moving from tall kneeling into flexed kneeling chops, performing high knees in sprint training,  or especially in crawling and climbing type actions, you must understand the mechanisms of internal rotation creation and stabilization -- if the glutes are not present and trained and useful in flexion, you are missing a chunk of something big. Amongst many other things, your client must be capable, stable, strong and skilled in moving from supine to quadruped all in one turning-over motion to teach how to stabilize the hip in the quadruped action and then progress into crawling.  This is a reflexive action learned in the early motor developmental phase of locomotion.  So take your client back through this motor pattern if they have some of the hip problems with internal rotation, it is a small piece of the gluteal puzzle.

I am sure this will show up in someone's seminar at some point, hopefully it is in many already, it has always been in my lectures when going down the rabbit hole of all things glutes. And to be fair, I haven't been to seminars in years as I get too frustrated, so this concept may be everywhere for all I know (lets hope).  But that is something I have to get over, I am sure I still have much to learn.  

To give credit where credit is due, which we always insist upon here at The Gait Guys, this was refreshed in my mind by Greg Lehman in a Facebook post forwarded to me by the inquiring doctor.   Link here  and from the article that spurred him to discuss it, an old article I read long ago just after completing my residency, the article is by Delp et al.  It is worth your time.  Thanks Greg for bringing this back into the dialogue, it is critical base knowledge everyone should already know. 

Variation of rotation moment arms with hip flexion.  Scott L. Delp,*, William E. Hess, David S. Hungerford, Lynne C. Jones  J. of Biomechanics 32, (1999)

-Dr. Shawn Allen, the other Gait Guy

link: https://www.thegaitguys.com/thedailyblog/2016/12/7/the-glutes-are-in-fact-great-internal-hip-rotators-too-open-your-mind

Pincer Toe nails: You've seen them; did you know what they were and how they got that way? Or, did you dismiss them?

We think Hitomi’s hypothesis is correct. Here is why (this is paraphrased from our blog post on subungal hematomas and our revolutionary thinking on why they occur and it seems to fit well with pincer nail formation as well).

… when the skin is pulled at a differential rate over the distal phalange (from gripping of the toes rather than downward pressing through the toe pad) there will be a net lifting response of the nail from its bed as the skin is drawn forward of the backward drawn phalange (there is a NET movement of skin forward thus lifting the nail from its bedding). For an at-home example of this, put your hand AND fingers flat on a table top. Now activate JUST your distal long finger flexors so that only the tip of the fingers are in contact with the table top (there will be a small lifting of the fingers). There should be minimal flexion of the distal fingers at this point. Note the spreading and flattening of the nail. Now, without letting the finger tip-skin contact point move at all from the table, go ahead and increase your long flexor tone/pull fairly aggressively. You are in essence trying to pull the finger backward into flexion while leaving the skin pad in the same place on the table. Feel the pressure building under the distal tip of the finger nail as the skin is RELATIVELY drawn forward.] This is fat pad and skin being drawn forward (relative to the phalange bone being drawn backward) into the apex of the nail. Could this be magnifying the curvature of the nail and not offsetting the “automatic curving and shrinkage” function of the nail ? We think it is quite possible.

We have more to say on this topic, the above is just an excerpt of our blog post. More here, in the link below

The season to pathologize our feet is upon us. Toe extension matters.

I blew out my flip flop,
Stepped on a pop top;
Cut my heel, had to cruise on back home.
But there's booze in the blender,
And soon it will render
That frozen concoction that helps me hang on. - Jimmy Buffett

I continue to see more and more people with inadequate toe extension. It is complicated. I see those who do not even have the awareness of toe extension, loss of strength of toe extension, loss of endurance of toe extension, loss of global range of toe extension (dorsiflexion at the MTP joint), more failure of long toe extensor (EHL) strength and more prominence of increased short toe extensor strength (EDB) and more frightening, a lack of disassociation of toe extension (MTP dorsiflexion) and ankle dorsiflexion. Many clients when asked to life their toes, will drive into ankle mortise dorsiflexion; ask them to just purely toe dorsiflex and the mental games begin, a wrinkled brow, intense concentration. If you cannot extended the toes sitting, how are you going to find them in swing phase of gait when balance, and other things, are more important?
Stand and lift your toes. The arch should go up, you have engaged the Windlass Mechanism, that winds up the plantar fascia and raised the arch. If you do not have competent, unconsciously competent, toe extension, your arch is not all that it can, and should, be. If you cannot raise your toes, thus raise the arch, thus plantarflex the first metatarsal, then in gait, when the foot is on the ground, you cannot properly position the sesamoids, properly get safe terminal ranges of hallux dorsiflexion at toe off, properly position the foot for loading and unloading, adequately achieve ankle dorsiflexion, adequately offer the hip a chance for ample hip extension, offer the glutes optimal chance to work in all phases to help control spin of the limb during loading and unloading, and the list goes on and on. I am sure I left much out there, this was written in a few minutes and unedited, just a short rant for the weekend. But if you have not championed toe extension, both in an unloaded and loaded foot (on the ground), achieved control of both long and short extensor muscles to the toes (and paired them well with the long and short toe flexors), disassociated toe extension from ankle dorsiflexion, and then figured out how to properly, timely, engage all these processes into your gait unconsciously, you are working on less of an optimal system than you should be. So, if your feet hurt, hips hurt, or a plethora of other problems that you are trying to fix with orthotics or other toys, maybe start with, "can you lift your toes?". It is a piece of the puzzle, trust me.
Or, you can just stay in your flip flops and perpetuate your toe flexion and wait for bad things to take root After all, tis the season soon !
Yes, toe extension in flip flops (we must flex our toes to keep them on) is as rare as a good multi-tasking man.

Shawn Allen, one of the gait guys.

Functional Ankle Instability and the Peroneals

Lots of links available here with today’s blog post. please make sure to take your time and check out each one (underlined below) 

As you remember, the peroneii (3 heads) are on the outside of the lower leg (in a nice, easy to remember order of longus, brevis and tertius, from top to bottom) and help to stabilize the lateral ankle. The peroneus brevis and tertius dorsiflex and evert the foot while the peroneus longus plantarflexes and everts the foot. We discuss the peroneii more in depth here in this post. It then is probably no surprise to you that people with ankle issues, probably have some degree of peroneal dysfunction. Over the years the literature has supported notable peroneal dysfunction following even a single inversion sprain event. 

Functional ankle instability (FAI) is defined as “ the subjective feeling of ankle instability or recurrent, symptomatic ankle sprains (or both) due to proprioceptive and neuromuscular deficits." 

Arthrogenic muscle inhibition (AMI) is a neurological phenomenon where the muscles crossing a joint become "inhibited”, sometimes due to effusion (swelling) of the joint (as seen here) and that may or may not be the case with the ankle (see here), or it could be due to nociceptive input altering spindle output or possibly higher centers causing the decreased muscle activity. 

This paper (see abstract below) merely exemplifies both the peroneals and FAI as well as AMI.

Take home message?

Keep the peroneals strong with lots of balance work!                                                             

2009 May;37(5):982-8. doi: 10.1177/0363546508330147. Epub 2009 Mar 6.

Peroneal activation deficits in persons with functional ankle instability.

Palmieri-Smith RM, Hopkins JT, Brown TN.

Source

School of Kinesiology, University of Michigan, 401 Washtenaw Avenue, Ann Arbor, MI 48109, USA. riannp@umich.edu

Abstract

BACKGROUND:

Functional ankle instability (FAI) may be prevalent in as many as 40% of patients after acute lateral ankle sprain. Altered afference resulting from damaged mechanoreceptors after an ankle sprain may lead to reflex inhibition of surrounding joint musculature. This activation deficit, referred to as arthrogenic muscle inhibition (AMI), may be the underlying cause of FAI. Incomplete activation could prevent adequate control of the ankle joint, leading to repeated episodes of instability.

HYPOTHESIS:

Arthrogenic muscle inhibition is present in the peroneal musculature of functionally unstable ankles and is related to dynamic peroneal muscle activity.

RESULTS:

The FAI patients had larger peroneal H:M ratios in their nonpathological ankle (0.399 +/- 0.185) than in their pathological ankle (0.323 +/- 0.161) (P = .036), while no differences were noted between the ankles of the controls (0.442 +/- 0.176 and 0.425 +/- 0.180). The FAI patients also exhibited lower EMG after inversion perturbation in their pathological ankle (1.7 +/- 1.3) than in their uninjured ankle (EMG, 3.3 +/- 3.1) (P < .001), while no differences between legs were noted for controls (P > .05). No significant relationship was found between the peroneal H:M ratio and peroneal EMG (P > .05).

CONCLUSION:

Arthrogenic muscle inhibition is present in the peroneal musculature of persons with FAI but is not related to dynamic muscle activation as measured by peroneal EMG amplitude. Reversing AMI may not assist in protecting the ankle from further episodes of instability; however dynamic muscle activation (as measured by peroneal EMG amplitude) should be restored to maximize ankle stabilization. Dynamic peroneal activity is impaired in functionally unstable ankles, which may contribute to recurrent joint instability and may leave the ankle vulnerable to injurious loads.

What do you know about Internal Tibial Torsion?

A great review on how ITT effects gait

The Gluteus Medius: Its not just for abduction anymore...

It would logically follow that the gluteus medius is important for generating both forward progression and support, especially during single-limb stance suggesting that walking dynamics are influenced by non-sagittal muscles, such as the gluteus medius, even though walking is primarily a sagittal-plane task. After midstance, but before contralateral preswing, support is generated primarily by gluteus maximus, vasti, and posterior gluteus medius/minimus; these muscles are responsible for the first peak seen in the vertical ground-reaction force. The majority of support in midstance was provided by gluteus medius/minimus (NOT the maximus), with gravity assisting significantly as well. The gluteus medius has also been highlighted as an abductor of the pelvis, working in concert with the contralateral quadratus lumborum (2), involved with keeping the pelvis level and abducting the pelvis on the stance leg side, such as when ascending stairs. 

Seemingly, the gluteals appear important for extension of the thigh during gait. One of the most common scenarios appears to be a loss of ankle rocker and resultant weakness of the gluteals (personal observations). Lets look at an example. 

Have you ever sat at the airport and watched people walk? I travel a great deal and often find myself passing the time by observing others gait. It provides clues to a plethora of biomechanical faults in the lower kinetic chain, like a loss of ankle rocker with people who wear flip flops or any other open backed shoes.

What is ankle rocker, anyway? According to Jaqueline Perry (THE Matriarch of Gait Analysis) during normal gait, the stance phase (weight bearing) foot depends on 3 functional rockers (pivots or fulcrums) for forward progression (3).

• heel rocker: at heel strike, the calacaneus acts as the fulcrum as the foot rolls about the heel into plantar flexion of about 10 degrees . The pretibial muscles must contract eccentrically to slowly lower the foot and help, along with forward momentum, pull the tibia forward
• ankle rocker: next, the ankle acts as at fulcrum and the tibia rolls forward due to forwardmomentum, with a maximum excursion of approximately 15 degrees. The gastroc and soleus should eccentrically contract to decelerate the forward progression of the lower leg.
• forefoot rocker: the metatarso-phalangeal joints act at the finalfulcrum in the stance phase of gait. Note that the 1st metatrso-phalangeal joint must dorsiflex65 degrees for normal forward progression, otherwise the individual will usually roll off he inside of the great toe. Tibial progression continues forward and the gastroc/soleus groups concentrically contract to decelerate the rate of forward limb movement. This, along with passive tension in the posterior compartment muscles, forward momentum , and the windlass effect of the plantar fascia result in heel lift.

Now watch someone walking in flip flops or open back shoes. There is no pivot past 90 degrees at the ankle (i.e. the tibia never goes beyond 90 degrees vertical). At this point the heel comes up (premature heel rise) and the motion must occur at the metatarso-phalalgeal joint. The only problem is that this joint usually has a maximum of 65 degrees extension, with 50 degrees needed for "normal" ambulation. Since more is now needed, the body borrows from an adjacent joints, namely the knee (which increases flexion) and the interphalangeal joints (which should be remaining flat and now must claw to “create” more available extension at the middle joint, as the proximal is nearly fully extended, through overactivity of the flexor digitorum longus. The tibialis posterior, flexor hallicus longus, and gastroc soleus groups also contract in an attempt to help stabilize the foot . Overactivity of these groups causes reciprocal inhibition of the long toe extensors and ankle dorsiflexors (tibialis anterior for example), causing the toes to buckle further and a loss of ankle dorsiflexion; in short, diminished ankle rocker function.

So there you have it. Glutes. They are a beautiful thing! Now get out there and improve their function!

1. Presswood L, Cronin J, Keogh J, Whatman C (2008). Gluteus Medius: Applied Anatomy, Dysfunction, Assessment, and Progressive Strengthening. Strength and Conditioning Journal, 30 (5), 41-53

2. J. Porterfield, C. DeRosa (Eds.) Mechanical low back pain. 2nd ed. WB Saunders, Philadelphia; 1991

3. Perry J, Burnfield JM, eds. Gait Analysis: Normal and Pathological Function. Journal of Sports Science & Medicine. 2010;9(2):353.

Got Ankle Rocker?

What do you know about ankle rocker? Here's a clip that will help you to learn more..

Coordination of leg swing, thorax rotations, and pelvis rotations during gait: The organisation of total body angular momentum

"In walking faster than 3 km/h, transverse pelvic rotation lengthens the step (“pelvic step”).
The shift in pelvis–thorax coordination from in-phase to out of phase with increasing velocity was found to depend on the pelvis beginning to move in-phase with the femur, while the thorax continued to counter rotate with respect to the femur. "

We are always trying to bring greater understanding to this group at TGG regarding gait mechanics. One must understand the implications of rotational work, and anti-rotational work on the phasic and antiphasic nature of the thorax and the pelvis. We have talked about becoming more phasic when there is spine pain. With today's study, we delve just al little deeper, particularly noting how the pelvis and the femur moving together first, before that is offset by the antiphasic nature of the thorax at higher speeds of gait.
This article uses the terms in phase and out of phase. We have learned over time that those terms to relate more so the description of how the limbs are, or are not, pairing up when a couple is walking together. None the less, the reader here should understand how they are referring to out of phase as antiphasic.

http://www.sciencedirect.com/…/article/pii/S096663620700135X

Ankle inversion sprain ? or off-loading photo ?

How we do one thing, is how we do all things.

I was sitting having my morning coffee earlier than normal this morning, which left me time to ponder some things.
Look at this picture, is this not a magnification of the "cross over gait" x100 ? Thus, is that planted foot not inverted ? Yes, it has to be, to a degree, a high degree. There is a reason why soccer players have a great affinity for ankle sprains.
When we have a narrow based gait, we are most likely going to strike more laterally on the foot, more supinated, if you will. If you widen step width, less inversion, less lateral forces (typically) and less supination (typically) compared to a narrow based gait.
If we descend stairs with our feet in a more narrow based gait, we are not only going to be inverted more, but striking at the ball of the foot, thus, more on the lateral foot tripod. This is the typical inversion sprain injury position.
When we jump, we should be trying to land with our feet more abducted, certainly not narrow based, because if we are too narrow we are at more risk for the same lateral forefoot landing and thus ankle inversion event. Just like descending stairs.

We see plenty of ankle inversion events. Why?
Because most people do not have enough hip abduction or peroneal skill, strength, endurance and they are unaware of their weak gait patterns or their ankle spatial awareness. Many have lazy narrow based gaits and insufficient proprioceptive awareness. And, they carry these things over into running, walking, jump landing (ie. volleyball, basketball, etc), and descending stairs, just to name a few.

How we do one thing, is how we do all things (mostly).

Rickie Lovell As he struck the ball it would been everted. The momentum of the follow through will have off loaded the everted foot as the energy moves in a similar line to that of the ball. It is extremely rare for a footballer to get a sprain from this, I certainly didn't see over several years working in professional football.
On a side note, find some footage of David Beckham taking free kicks - the mechanics are astounding!

The Gait Guys possibly everted, but no guarantee.It still looks pretty inverted to me.But we see your point, and is a real good one, real good. Super good. We will check our the bender-man thanks for chiming in with such great insight !

The Gait Guys yes, the momentum of the leg kicking across the body would externally spin the stance leg. The picture is likely showing the offloading phase, not the loadin

Rickie Lovell The benefits of being a Brit that used to play!