Try THIS at home...

Cool test, results you can see and some literature to back it up. If you are interested at all in proprioception, this is an interesting read.

So, the question for us is: "Does ankle dorsiflexion actually create more stability, like is purported?"

“The point is that if I make their ankle rigid this way, then they can more effectively use the balance mechanisms at their knees, hips, and proximally, because they’re on a stable base. My proposition is that their balance is actually normal, apart from that distal segment. When their ankle is stabilized, they use their knees more effectively, and they become less dependent on their eyesight to maintain their balance.”

http://lermagazine.com/article/afos-and-balance-issues-in-peripheral-neuropathy

The Calcaneo Cuboid Locking Mechanism...Revisited...

Do you know what this is? You should if you treat folks who walk or run!

It is the mechanism by which the tendon of the peroneus longus travels behind the lateral malleolus of the ankle, travels underfoot, around the cuboid to insert into the lateral aspect of the base of the 1st metatarsal and adjacent 1st cunieform. Remember the peroneus longus?

The peroneus (or fibularis) longus arises from the head and upper two-thirds of the lateral surface of the fibula, from the deep surface of the fascia, and from the intermuscular septa between it and the muscles on the front and back of the leg; occasionally also by a few fibers from the lateral condyle of the tibia.  You can see from it attachments that it can influence the entire upper lateral leg.

It’s tendon runs down the fibular shaft, wraps around the lateral malleolus, travels obliquely under the foot, crossing the lateral cuboid (which it everts after midstance to help with supination) crosses the sole of the foot obliquely, and inserts into the lateral side of the base of the first metatarsal and lateral aspect of the 1st cunieform.  

It acts from just prior to heel strike to limit excessive rearfoot inversion, through midstance to decelerate subtalar pronation and assists in stabilization of the midfoot articulations, and into terminal stance and pre swing to lock the lateral column of the foot for toe off and plantar flex the 1st ray (creating a good foot tripod), allowing dorsal posterior shift of the 1st metatarsal-phalangeal joint axis (necessary for dorsiflexion of the hallux (big toe)).

When the peroneus longus contracts, in addition to plantar flexing the 1st ray, it everts the cuboid and locks the lateral column of the foot, minimizing muscular strain required to maintain the foot in supination (the locked position for propulsion). Normally, muscle strength alone is insufficient to perform this job and it requires some help from the adjacent articulations.

In addition, the soleus maintains spuination during propulsion by plantar flexing and inverting rear foot via the subtalar joint. This is assisted by the peroneus brevis and tertius which also dorsflex and evert the lateral column, helping keep it locked. Can you see why the peroneii are so important?

signs of a faulty calcaneo cuboid locking mechanism

• weak peroneus longus, brevis and or tertius
• excessive rear or midfoot pronation
• low arch during ambulation
• poor or low gear “push off”
• subluxated cuboid

The calcaneo cuboid locking mechanism. Essential for appropriate supination and ambulation. Insufficiency, coming to a foot you will soon examine.

Sagittal gait change in arthritic hips.

Asymmetries are the norm, whether they are anatomic or functional. This however does not mean that there may, or may not, be present or future consequences to the asymmetries.  It can take time for compensations to develop to accommodate these compensations, and it may take even further time for the body to present (and perhaps not present) consequences to the compensations.

In this study, progressing osteoarthritis in the hip began to eat away as some functional parameters that might otherwise have allowed for more symmetrical step and strike lengths, and one must not forget step width has to be in this discussion as well. 

"The patients walked significantly slower than the controls (p=0.002), revealed significantly reduced joint excursions of the hip (p<0.001) and knee (p=0.011), and a reduced hip flexion moment at midstance and peak hip extension (p<0.001). Differences were primarily manifested during the latter 50% of stance, and were persistent when controlling for velocity." - Eitzen et al.

Thus, to walk a straight line, some adaptive compensations will have to occur in the body to enable a linear progression. This might mean altering hip extension patterns, altering hip rotation relationships within the affected hip and thus of the contralateral hip (which might lead to pelvis distortion patterning), pelvis drift in the frontal plane, pelvis drift in the sagittal plane (APT, PPT), asymmetries in spinal rotation and thus arm swing, to name a few just regionally at the hip-pelvis-spine interval. Adaptations must be made. The question is, does your gait assessment afford you the insight to be addressing the problem, or merely their visible compensation, that is the hard part.  And remember what we always say, you gait analysis is only going to show you what your client is doing, not why they are doing it. Thus, fixing what you see is likely not fixing
"the why".

"Reduced gait velocity, reduced sagittal plane joint excursion, and a reduced hip flexion moment in the late stance phase of gait were found to be evident already in hip osteoarthritis patients with mild to moderate symptoms, not eligible for total hip replacement. " - Eitzen et al.

* Differences were primarily manifested during the latter 50% of stance, and were persistent when controlling for velocity.

https://www.ncbi.nlm.nih.gov/pubmed/23256709

BMC Musculoskelet Disord. 2012 Dec 20;13:258. doi: 10.1186/1471-2474-13-258.
Sagittal plane gait characteristics in hip osteoarthritis patients with mild to moderate symptoms compared to healthy controls: a cross-sectional study.
Eitzen I1, Fernandes L, Nordsletten L, Risberg MA.

Body Composition and gait speed.

"In older adults, every 0.1-m/s slower gait speed is associated with a 12% higher mortality. However, little research has identified risk factors for gait-speed decline."

Reduction in activity, particularly challenging difficult activity, stuff that asks a little more from you, the typical stuff that the elderly do not wish to engage in, is a bigger piece to their gait and movement decline that they likely think.

Conclusions: "High and increasing thigh intermuscular fat are important predictors of gait-speed decline, implying that fat infiltration into muscle contributes to a loss of mobility with age. Conversely, a decreasing thigh muscle area is also predictive of a decline in gait speed."

https://www.ncbi.nlm.nih.gov/pubmed/23364001

Am J Clin Nutr. 2013 Mar;97(3):552-60. doi: 10.3945/ajcn.112.047860. Epub 2013 Jan 30.

Associations between body composition and gait-speed decline: results from the Health, Aging, and Body Composition study.

Beavers KM1, Beavers DP, Houston DK, Harris TB, Hue TF, Koster A, Newman AB, Simonsick EM, Studenski SA, Nicklas BJ, Kritchevsky SB.

Internal hip rotation and low back pain.

Internal hip rotation and low back pain.

No brain surgery here if you have been on our station for the last several years. We pound home the critical importance of internal hip rotation all the time, here and in our clinic.
When the foot is on the ground, loading, the opposite leg is in swing. Part of this swing phase requires the hemipelvis on that swing side to also advance forward as well. This means that the stance phase leg will see the pelvis rotating atop of the static femoral head, this rotation is internal hip rotation. If one does not have sufficient internal hip rotation then the heel will be lifted prematurely, the foot might undergo an adductory twist (the heel moves medially into adduction which can look like the foot spinning "relatively" outward into external rotation) to name just a few (of many possible) pattern consequences. The loads can also move up into the lumbar spine, because, if the rotation is not there in the hip, or not buffered there, it either moves down into the limb or up into the pelvis and spine, or both. There are many strategies and patterns of loading responses available to the framework, it is your job to find them, source out the problem, and remedy. One must look for and understand the importance of sufficient internal hip rotation in your client, and the ramifications when it is not sufficiently present.
This study brings this principle to mind.

https://www.ncbi.nlm.nih.gov/pubmed/26751745

Have impaired ankle rocker or ankle dorsiflexion ? Try out these shoes.

Have impaired mid or forefoot rockers?

This will come to little surprise to anyone who has been here awhile at TGG. But I finally got around to putting on a pair of the HOKA Bondi 5 recently and boy was I surprised how much rocker was built into the forefoot. I can now see why there is such a dramatically beneficial response to patients with a painful hallux joint complex. I had been in their Claytons and Cliftons before to trial them out, but never a pair of Bondi 5's.
If you have a client with impaired mid to late stage ankle rocker or forefoot rockers (there are 3 rockers, Heel Rocker, Ankle rocker, and Forefoot Rocker) this shoe will buffer the loads. It is no replacement for attempting to remedy biomechanical faults or limitations, but , if you have a client where solution is not available and management of loads i the only way, then this shoe will be a gem to you and the client. Go try a pair on so you know what we mean. The rocker is massive and effective, and one might argue, a little excessive (but we are not complaining). The Dansko clog can be another alternative for some clients.

https://www.ncbi.nlm.nih.gov/pubmed/19744753
Changes in running kinematics and kinetics in response to a rockered shoe intervention.
Boyer KA, Andriacchi TP.
Clin Biomech (Bristol, Avon). 2009 Dec;24(10):872-6. doi: 10.1016/j.clinbiomech.2009.08.003. Epub 2009 Sep 9.

Hoka Bondi or Dansko Clog

Neuromechanical adaptations in achilles tendinosis

It is not just about the tendon. A perspective on asymmetry.

We are coming back to this important article again.
When you have a tendon problem, you have other problems. There is the muscle-tendon relationship, there is the CNS component, and there are the other muscles regionally within the related loaded chains. Because of these multiple integrated components, this "illustrates the human body's capacity to adapt to tendon pathology and provide the physiological basis for intervention or prevention strategies".
"If a component in the loop loses its integrity, the entire system has to adapt to that deficiency. "
We have discussed on recent TGG podcasts this important ability of a tendon to have sufficient stiffness, to be more precise, to produce sufficient stiffness. Degenerative tendons exhibit less stiffness and so when this issue is present, we move into the adaptive strategies of the entire system that was alluded to above. Adaptation begins; agonist, synergist, antagonist muscles, CNS, motor pattern adaptive patterns ensue.
It has been suggested by this study that these compensations are unilateral, on the affected side, thus driving asymmetrical neuromechanical adaptations.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4553058/

Cannabis users walk differently.

We all have experienced or viewed the alcohol impaired gait at some point in our lives, the sloppy malcoordinated limb and torso movements. There are some classic observable characteristics there that many of us are familiar with. But what about cannabis gait ?

"The research from the University of South Australia, published in the journal Drug and Alcohol Dependence, found those who smoke cannabis tend to move their shoulders less and elbows more as they walk. The pilot study also found marijuana users swing their knees more quickly during walking. The differences in gait were small and found in people who smoked a light or moderate amount of cannabis. Some changes were so small it was impossible for a specialist to detect."

However, the thing we found interesting was the papers final question, as to whether the subtle gait changes over a longer period of time would increase or become more apparent.

*We have seen this variation in arm swing gait many times before. We have discussed numerous times that when there is a reduction in the normal shoulder and pelvic "girdle" counter rotations, the normal antiphasic gait that presents us with the clearly obvious opposite arm-leg swings, we lose the ability to tap into these oscillations that afford us this free arm and leg swing. So, when these girdle rotations are reduced, the limb movement has to come from further down into the limb, from elbow movement, a sort of casting the lower arm forward from biceps and triceps activity and from a kicking forward of the lower leg from quadriceps activity instead of hip flexion-extension activity.

Gait affects everything, and everything seems to affect our gait.

https://www.9news.com.au/national/2017/09/01/15/25/marijuana-users-walk-differently-australian-study-claims

Lumbar spine mechanics and boots

Your footwear can affect your hips and low back ? Yes.

If you have been with us even a short while, this study should be of zero new value to you. But this study looked at the ankle dorsiflexion restricting firefighting boots on the low back.
We know that there are several force dissipators in the lower limbs, those being hip flexion, knee flexion and ankle dorsiflexion not to forget the all important foot pronation. When one of those is compromised, the job of that joint complex typically gets shunted elsewhere, and often proximally into the body.
Obviously, above ankle boots will restrict ankle dorsiflexion. Imagine an ice skate laced up all the way, or a ski boot, the ankle dorsiflexion virtually disappears. The came can happen in an inappropriately laced hiking boot or high ankle trail running shoe.
This will hit home the posts earlier in the week on the "z-angle" we discussed and Gray Cooks video from the weekend.
It is possible if you dial back the ankle dorsiflexion you cheat hip extension, or you make the lumbar spine extend into more lordosis than it is happy to perform.
You just cannot rob Peter to pay Paul all the time. Eventually Peter is gonna get pretty pissed.

http://www.sciencedirect.com/…/article/pii/S0003687017301333

More on the Z-angle

More on the "Z-angle". Why your hip and ankle have to talk to each other.

We have been saying this kind of stuff for years, but in this video perhaps Gray Cook says it in a way that will resonate well with some when we can be a bit too wordy at times, Gray is always eloquent and well spoken. We often discuss this ankle and glute relationship he mentions in a topic we refer to as "the Z- angle". And, we discuss the greater global ramifications of unresolved ankle sprains. Search our blog for these terms and topics.
It is rare that our in-office therapy and our corrective home work for a client does not address both the ankle and hip simultaneously. We know this tight relationship exists, and so should you.
In many of our podcasts and blog posts we pound sand on the fact that just because you have ankle mobility on the exam table does not mean you will have it available in some movement patterns or in some of your sport movements. And, ankle functional impairments are key players in multiple injuries and impaired movement patterns. We like the "software vs hardware" terminology he uses, we will be borrowing that verbiage in the future, it is a nice way to tighten up a dialogue without getting wordy. Great job as always Gray !
https://www.youtube.com/watch?v=U93MoOxN49c

Forefoot Varus vs Forefoot Supinatus

We talked about forefoot varus, forefoot supinatus and subsequent biomechanics in a recent onlinece.com course. Here is a great commentary on a review article we discussed as well as a great explanation about thew tru differences between at forefoot varus (rare) and the more common forefoot supinatus.

Take home message? FROM THE ARTICLE:

" In summary: both look the same, but they are totally different beasts:

    a forefoot varus is bony and a forefoot supinatus is soft tissue
    a forefoot varus is a cause of ‘overpronation’ and a forefoot supinatus is the result of ‘overpronation’
    a forefoot varus is rare and a forefoot supintus is common
    a forefoot varus cannot be corrected and a forefoot supinatus can be corrected"

http://www.runresearchjunkie.com/the-effect-of-forefoot-varus-on-the-hip-and-knee-and-the-effect-of-the-hip-and-knee-on-forefoot-supinatus/

A shoe inside a shoe ? . . . yup !

Have you ever used a "shoe in a shoe" to solve a problem? We did and it was magical ! (see photo below)

2 things you may have missed last night if you were not on our seminar call at onlineCE.com. but no worries, we had the course recorded, look for Biomechanics 323 in a week or so. It is in our catalogue of courses, you can take them all and go deep down the Gait Guys rabbit hole any day of the week ! If you can't find the rabbit hole, message us or email us.

Your gait analysis is lying to you more than you think. The more difficult motor program your client is running occurs before the gait analysis even begins.

Even before you client walks back to your treatment room, there are several things that we may not be aware of. Gait initiation is a different and more complex motor program than the simple gait motor program.

Here is a little something we do in our clinics, all the time. When the session room is open for the next client, we greet our client in the lobby. We do not have our staff send them back to the room to change and wait for us. We watch them closely, but without them knowing. How does the client stand up? How do they initiate their gait cycle ? How is their balance? How do they carry their bags, purse, backpack ?
We ask them to head back to the session room to get changed, letting them think we are grabbing a drink of water. And then, in a sneaky manner, we watch them stand, initiate gait, and walk back to the room.
We do this, because, gait initiation is separate motor program. It requires several component parts, a squat, weight shift, double support balance acquisition, COP (center of pressure acquisition), step length precalculations, step width precalculation, foot strike targeting, weight shift again, initial weight transition, and then the gait cycle. And gait initiation is different and asymmetrical in people with pain, we know this for a fact in clients with painful osteoarthritis. These clients develop adaptive posturomotor strategies that shorten the monopodal phase on the affected leg.*
For many gait disorders, these are the component parts that will first show up if there is a problem in the system. Gait initiation is more difficult than gait perpetuation. Besides, how we walk when we do not think we are being watched, when we are carrying our things (purse, phone, bottle of water, backpack, etc) is how we typically walk. Clients will show all the goodies we need to see: the turned out foot, the hiked shoulder, the limps, the staggers, stumbles, speed, step width, and the like. We also get to see how they move in the shoes they live in, the heeled ones, the broken down ones, the work shoes.

So, when your client is having a formal treadmill gait analysis, what are you seeing? Their best behavior, or the truth ? One thing is for sure, you do not see the most important program the precedes their treadmill analysis, namely, how they get out of the chair and up onto the treadmill. This stuff matters.
There are clues everywhere, grab all of them, in as natural a manner as possible.

The Gait Guys

*Arch Phys Med Rehabil. 2000 Feb;81(2):194-200.
Asymmetry of gait initiation in patients with unilateral knee arthritis.
Viton JM1, Timsit M, Mesure S, Massion J, Franceschi JP, Delarque A.

Parkinsons Patients? How about textured insoles or walking barefoot more?

Is it at all surprising that increasing afferent input (in this case: textured insoles) to one of the areas in the brain (parasaggital sulcus in the post central gyrus) from one of the structures that has the greatest cortical representation (ie the feet) can improve gait on folks that have a disorder with their basal ganglia (which provides background positioning of joints)?

"After one week of insole wear, plantar sensation and stride length were significantly improved relative to baseline; the improvement in plantar sensation was maintained after another week of wearing conventional insoles."

Lirani-Silva E, Vitorio R, Barbieri FA, et al. Continuous use of textured insole improve plantar sensation and stride length of people with Parkinson disease: A pilot study. Gait Posture 2017;58:495-497.

Asymmetry doesn't matter?

Asymmetry doesn't matter?
There were many people jumping on the Usain Bolt "asymmetry doesn't matter" train in the last few weeks after all the discussion on his scoliosis and leg power differentials. Now nothing but silence.
We think asymmetry matters, and we wrote about it all last week.
What if Bolt were just a little more symmetrical ? Would he have been a little faster ? Is Gatlin faster or just more symmetrical ? Lucky race? I bet Gatlin doesn't think so or care, nor does Coleman. LOL. Fuel for the fire. We will stand our ground however.

We are not pointing fingers or picking on anyone, fact of the matter is we love the good debates that have been going on. That is where the learning occurs. We are always happy to be wrong, as long as we leave a debate smarter than when we went in to it.
#crickets #maybeasymmetrymatters

Addendum worth adding here (from comments below):

Eric A Johnson , asymmetry is the law/rule. How much is too much? No one can answer that. But if we drive a patient towards less asymm and they don't have pain, injury incidence reduces, their chronic complaint becomes less of issue or resolves, or if performance improves...... then maybe, just maybe, their asymmetry mattered. #noguarantees #wishwecouldclone #crystalballs

And . . . if Bolt had won, everyone would be just saying that more proof that asymmetry is ok, ignore asymmetries in your clients.
Fact of the matter is, as we said in our post, that asymmetries are the norm, the rule of law, but that does not mean that asymmetries are not an issue in some people and some athletes. When is an asymmetry too much that it poses an injury risk or a performance loss ? No one knows until we can clone people, but there is a tipping point in everyone where it is just plainly too much to risk. That is the point of the discussion.
So, we are glad Gatlin and Coleman beat Bolt. Only because an older guy beat the King are we having this discussion, thankfully. Which is really what matters here, the discussion, instead of defending ones flag because of one journal article that has a big unknown hanging over it.

We have acquired the asymmetry study below.
We hope to have something to share that helps in the asymmetry dialogue. The authors did quote "To the authors’ knowledge, this is the first study to present the magnitude of asymmetry in sprinters with mean maximal velocity >10 ms-1 " So anyone hanging their hat on one study should consider pulling back on the reigns a little before planting their flag. More research needs to be done.

To clarify our stance, since it became clear in the ensuing debate yesterday that our perspective was not well postured, that we are talking about physical biomechanical asymmetries in muscle strength, power, endurance, skill and torsional issues, functional leg length differences, etc. Not performance asymmetries that may result from these asymmetries. We apologize for our lack of clarity, we all at times assume that others we debate with know what angle we are jousting from, hence why debate is good, to clarify all the factors and find some better answers and common (or uncommon) ground.
We also will assume that most of those debating yesterday from the article's perspective, had likely not read the article either since it was just released and is a fee-based paper.

For those wondering, here were the variables looked at:
"The following variables were included in analyses;
step length, step rate, contact time , aerial time, touchdown angle (for the stance leg), knee separation (assessed as inter-thigh angle) at touchdown, lift-off angle, thigh - and knee angle at lift-off (for the stance leg), maximal thigh flexion, range of thigh motion, rear knee flexion at maximal thigh extension, and horizontal ankle velocity (of the lateral malleolus marker for the soon -to -be stance foot) relative to CoM"

Our stance would be, based off our comments previously, if these things were asymmetrical, could driving the client toward greater symmetry, result in better outcome performance. That was and is, our thought experiment.

This was a dialogue we had recently and we have been messaged on it numerous times. Don't get too rigid in your beliefs, it might come back to bite you (that goes for us too). It is best we all keep our eyes and minds open. Science moves forward, so don't plant your flag so far in the ground that you can't pull it up when the landscape of knowledge moves the frontline further ahead.

Paraphrased:
Research has not yet provided all the answers to all our questions in the study of the human frame. There are plenty of studies we have all found that are flawed, so we are not going to always agree with research, research is a starting place, a foundation work from, but things change and they change fast sometimes . . . . just because something has not been validly proven yet (or disproven) in research doesn't mean it is not going to be nor does that proposed thought not deserve deeper thought . . . learning doesn't stop at the end of the pen of a researcher who may know a little less on a topic than others. Just because there is a published journal article on a topic doesn't necessarily make it a reliable paper or make it law or a template we must all embrace or "forever hold our peace". Challenging the present facts and knowledge doesn't necessarily always make it "bro science" either.
Question everything while working from a present day base of knowledge. And be ok with being called a bro, it can a compliment , sometimes, and sometimes not by those who may be feeling uncomfortable that their belief system may be quivering in uncertainty from some new paradigms in thought.

http://www.tmz.com/2017/08/05/usain-bolt-loses-final-solo-100m-race-justin-gatlin/

Walking: The brain leads the body by one step.

Researchers have discovered that we most accurately hit targets when we see them 1 to 1.5 steps ahead of where we were. This is more difficult that it seems because we are making a plan, and at the same time we're making that plan, we're making a movement based on the stuff that we saw a second and half in the past.
Below this link, you will find our post on projecting and estimating steps. Much along the same lines but with a great video to set it up.

https://www.axios.com/when-walking-the-brain-leads-the-body-by-one-step-1513304440-3035f0bb-a992-403f-b084-51e4205cda58.html
https://thegaitguys.tumblr.com/post/44642195883/the-funny-problem-with-the-stairs-at-brooklyns

Helping the shoes bend where you do.

Sometimes, when someone has a foot that is a half or whole size smaller and the shoe doesn't bend where their 1st MTP joint bends, you have to perform shoe surgery. Rather than throwing a pair of shoes away because its causing pain at the joint (and you have ruled out all other causes and this is the only pair of shoes that bothers them), sacrifice a few hundred miles on the newer shoes and make it bend where your client bends.

ADDENDUM to video:
Sometimes, when someone has a foot that is a half or whole size smaller and the shoe doesn't bend where their 1st MTP joint bends, you have to perform shoe surgery. Rather than throwing a pair of shoes away because its causing pain at the joint (and you have ruled out all other causes and this is the only pair of shoes that bothers them), sacrifice a few hundred miles on the newer shoes and make it bend where your client bends.

ADDENDUM: we recieved a good question about this, as to "Where and how deep etc" to make the cut.

the shoe bends momentarily before the toe bends, so i like to create the cut (start little, just enough for the client to feel the shoe now bends easier and is creating less pressure into the joint) , i like to create the cut about 2mm to where the metatarsalphalangeal joint bends, proximal on the sole of the shoe...... since the shoe will begin to flex at heel lifting before much toe dorsiflexion occurs. But, as ivo said, they are not bending at the regular build in toe break of the shoe (where it naturally breaks/bends) so you will typically be proximal to that toe break interval. And yes, start small, because the cut will grow larger, and often fast........so the shoe will trash out sooner. I encourage folks to return the shoe if it is new, it was a bad shoe fit......but if they have 50 miles or more on it and the shoe is not working, rather than trash them........play surgeon and learn ! The client will most likely say "that was it, the shoe bends easily now, i can toe off comfortably".......... until the cut extends and ruins the shoe. In my experience that is about at another 150 miles

Trying again here. VIDEO CASE: Is this lateral compartment weakness ?

Quite simply, there are too many people playing doctor out there that do not have the ability to examine their clients appropriately. Here is another case of just that.
It is clear that this client has left lateral compartment deficits. Or is it too much medial compartment tone ? Your screens and loading tests will not likely show you this specifically, this client may merely present, as they did in this case of left frontal plane hip-pelvis drift and a right cross over step. If you have been with us for awhile, you know these 2 match up when it comes to locomotion. But one must solve the "Why" for the "how" to be accurate (how to fix it).
But, if you are looking for weakness, you will find it here, yes, peronei and lateral gastroc are weak. But is it inhibition or neurologic or frank weakness ? It is because of heightened medial compartment tone ? It could be, thus making one think of possible centrally mediated processes.
And, is the ankle the source or the frontal plane drift (glute weakness) the source ? Cart or the horse ? Chicken or the egg ? You have to examine your clients, on and off their feet, shoes off, socks off (yes, i took the socks off afterwards). Screens are not enough if you are trying to solve problems. Fixing how your client's improper loading is not a fix always, it could merely be teaching a compensation over a compensation to a problem. Be smarter than the rest, get the knowledge to examine your clients deeper , and more specific, function. Then, how they are moving, and the movements that you see that you do not like, will make more sense.
in this case, if you do not address the foot and the hip abductors and pelvis stabilizers, you lose, and so does your client as you build more strength into their asymmetry . . . . eventually leading, possibly, to complaints.

Gait and peripheral arterial disease

When we think of slowing gait we think of the elderly. There is nothing new in this regard and there have been plenty of papers supporting the cognitive decline the coincides with this aging population. There is even correlation to increased fall risk, which matches up with significant fall mortality studies. Reduced, especially right sided, hippocampus volume and function is the current suspect in most research, and it is linked to some impairments in non-verbal memory and the slowing of gait.

Here, we see that PAD (peripheral arterial disease) can also cause a slowing of gait, particularly in stair ascent in this particular study. PAD can cause intermittent claudication pain in the calf and result in altered gait mechanics during level walking as well. The study found that those with claudication walked more slowly than healthy controls. They also found that there was reduced vertical ground reactive forces, reduced knee extensor moment during forward continuance, reduced ankle angular velocity at peak moment and reduced ankle power generation. They were also able to determine that the slower gait was related to the claudicated limb, that limb was the one that set the speed of gait. In other words, the system down regulated to the affected limb's capability. The study highlighted the importance of maintaining plantarflexor strength and power in those with peripheral arterial disease with effective claudication.

Sagittal plane joint kinetics during stair ascent in patients with peripheral arterial disease and intermittent claudication. Stephanie L. King, Natalie Vanicek, Thomas D. O’Brien

Degenerative Achilles tendons have reduced stiffness.

On yesterday's podcast 127 recording (launch in 3 weeks), we go down this rabbit hole. A worthy hole.
This is important stuff, if you are treating people, (unlike Joe Rogan and the Scibabe, soft slap there, they should use their platform to interview really smart people when it comes to medicine :), you need to know this stuff.

"Achilles tendon, when degenerated, exhibits lower stiffness. This local mechanical deficit may be compensated for by an alteration of motor commands from the CNS. These modulations in motor commands from the CNS may lead to altered activation of the agonist, synergist and antagonist muscles. "

https://www.ncbi.nlm.nih.gov/pubmed/26046962