Where do you want to load your foot in relation to your center of mass ?

Who do you want to be ? The guy loading his head over his foot
(narrow step width), or the gal loading the head and COM inside the foot (less narrow step width) ?
It is not hard to guess who is gonna be faster and more powerful from these photos. The lady is stacking the knee over the foot, the hip over the knee and stabilizing the hip and pelvis sufficiently and durably to keep the pelvis level for the next powerful loading step, and the other is flexion collapsing into the stance phase knee, insufficiently loading the hip and thus dropping the opposite side pelvis. He is not stacking the joints, there is a pending cross over (look at the swing leg knee approaching midline with barely any knee spacing, thus guaranteeing a cross over step or at the very least a very narrow step width.)
Sure, some one is going to say one is a distance runner and the other is a sprinter. Yes, and our point is that the sprinter is not head-over-foot, the one with all the highly suspect flaws is head over foot ! Wider step width means more glutes. Go ahead, walk around right now with a very narrow step width and see how little efficient glute contraction you get, then walk with a notably wider step width, and you will see wider means more glutes. Keep your COM moving forward, not oscillating back and forth sideways over each stance foot, that is a power leak.

The distance runner is showing sloppy in technique. Say what you want, but one of these runners is weak and very likely at greater risk for injury, the other is strong and durable, and likely at less risk for injury.
If you ask us, but what do we know . . . .
So, again, was ask . . . . which one do you want to be ?

Dual tasking and neurocognitive decline.

Your holiday homework . . . . look for the gait clues Ivo and Shawn have talked about this year (*see below)

Dual tasking and neurocognitive decline.
Mild cognitive impairment (MCI) is considered a predementia state associated with a 10-fold increased risk of progression to dementia. Dual tasking during gait may help predict neurocognitive decline.

So, When you are around aging family this holiday season, pay close attention to them when moving about around them. Dual tasking during gait should not be difficult for most healthy folks, but if you add in things that the aging population are challenged with (things like physical weaknesses, mild vestibular challenges, visual challenges , mild neuropathy, cold feet, proprioceptive losses) and then throw in some dual tasking (talking, carrying bags) we can often bring out predictors of future decline.
Remember, falls in the elderly are huge predictors of near term morbidity.

* Look for the clues during dual tasking or during intimidating situations (ie, crossing a busy street), look for things like slowing of gait, wider or narrower step width, shorter steps, frustration, confusion, reaching for support (grapping your hand or arm), stopping, shuffling, arresting of talk to negotiate an area, etc.

"A dual-task gait test evaluating the cognitive-motor interface may predict dementia progression in older adults with MCI (mild cognitive impairment)."

Association of Dual-Task Gait With Incident Dementia in Mild Cognitive Impairment
Results From the Gait and Brain Study. Manuel M. Montero-Odasso et al.
JAMA Neurol. 2017 Jul; 74(7): 857–865.

Circumducting gait , at the ankle level ?

We often circumduct a leg to get around a clearance problem. Sometimes the clearance problem is the leg length itself, and sometimes it is a foot clearance issue, one that doesn't dorsiflex/toe extend enough.

This is what the foot clearance circumduction strategy looks like (more clear on the left foot). It is a heavy peroneal, tib anterior (more lateral belly, interosseous) and lesser toe extensor strategy. The foot clearly dorsiflexes and everts the rear and fore foot during early swing. It is not until just before heel strike that the tib anterior seem to jump in to do its primary job of dorsiflexion AND inversion.
Finding out why a client is circumducting this way is the key. It could be from the opposite hip abductors being weak, and it could be poor abdominal control on the same side, or it could be down in the foot (perhaps extensor hallucis/big toe extensor) and of highest suspect is a weak or motor pattern delayed tib anterior. Bad lazy habits can happen around trivial weakness, and then can mushroom into other bigger things.

Your exam will help you.
Seeing a problem in someones gait is not their problem, it is their strategy to get around the parts that are not working well.

shawn allen, the other gait guy

#gait, #gaitproblems, #gaitanalysis, #anklerocker, #ankledorsiflexion, #shinsplints, #swingphase, #thegaitguys, #circumductinggait

The “Standing on Glass” Static Foot/Pedograph... PART 2

The “Standing on Glass” Static Foot/Pedograph... PART 2
We hope you find this case presentation dialogue interesting.

* note: This is a static assessment dialogue. One cannot, and must not, make clinical decisions from a static assessment. As in all assessments, information is taken in, digested and them MUST be confirmed, denied and/or at the very least, folded into a functional and clinically relevant assessment of the client before the findings are accepted, dismissed and acted upon.

Here is the case . . .

Part 2: “Standing on Glass” Static Foot/Pedograph Assessment

* note (see warning at bottom): This is a static assessment dialogue. One cannot, and must not, make clinical decisions from a static assessment. The right and left sides are indicated by the R and L circled in pink. There are 4 photos here today.

Blue lines: Last time we evaluated possible ideas on the ORANGE lines here, it would be to your advantage to start there.

We can see a few noteworthy things here in these photos. We have contrast-adjusted the photo so the pressure areas (BLUE) are more clearly noted. There appears to be more forefoot pressure on the right foot (the right foot is on the readers left), and more rearfoot pressure on the left (not only compare the whiteness factor but look at the displacement of the calcaneal fat pad (pink brackets). There is also noticeably more lateral forefoot pressure on the left. There is also more 3-5 hammering/flexion dominance pressure on the left. The metatarsal fat pad positioning (LIME DOTS represent the distal boundary) is intimately tied in with the proper lumbrical muscle function (link) and migrates forward toward the toes when the flexors/extensors and lumbricals are imbalanced. We can see this fat pad shift here (LIME DOTS). The 3-5 toes are clearly hammering via flexor dominance (LIME ARROWS), this is easily noted by visual absence of the toe shafts, we only see the toe pads. Now if you remember your anatomy, the long flexors of the toes (FDL) come across the foot at an angle (see photo). It is a major function of the lateral head of the Quadratus plantae (LQP) to reorient the pull of those lesser toe flexors to pull more towards the heel rather than on an angle. One can see that in the pressure photos that this muscle may be suspicious of weakness because the toes are crammed together and moving towards the big toe because of the change in FDL pull vector (YELLOW LINES). They are especially crowding out the 2nd toe as one can see, but this can also be from weakness in the big toe, a topic for another time. One can easily see that these component weaknesses have allowed the metatarsal fat pad to migrate forward. All of this, plus the lateral shift weight bearing has widened the forefoot on the left, go ahead, measure it. So, is this person merely weight bearing laterally because they are supinating ? Well, if you read yesterday’s blog post we postulated thoughts on this foot possibly being the pronated one because of its increased heel-toe and heel-ball length. So which is it ? A pronated yet lateral weight bearing foot or a normal foot with more lateral weight bearing because of the local foot weaknesses we just discussed ? Or is it something else ? Is the problem higher up, meaning, are they left lateral weight bearing shift because of a left drifted pelvis from weak glute medius/abdominal obliques ? Only a competent clinical examination will enlighten us.

Is the compensation top-down or bottom up, or both in a feedback cycle trying to find sufficient stability and mobility ? These are all viable possibilities and you must have these things flowing freely through your head during the clinical examination as you rule in/rule out your hands-on findings. Remember, just going by a screen to drive prescription exercises from what you see on the movement screen is not going to necessarily fix the problem, it could in fact lead one to drive a deeper compensation pattern.

Remember this critical fact. After an injury or a long standing problem, muscles and motor patterns jobs are to stabilize and manage loads (stability and mobility) for adequate and necessary movement. Injuries leave a mark on the system as a whole because adaptation was necessary during the initial healing phase. This usually spills over during the early movement re-introduction phase, particularly if movement is reintroduced too early or too aggressively. Plasticity is the culprit. Just because the injury has come and gone does not mean that new patterns of skill, endurance, strength (S.E.S -our favorite mnemonic), stability and mobility were not subsequently built onto the apparently trivial remnants of the injury. There is nothing trivial if it is abnormal. The forces must, and will, play out somewhere in the body and this is often where pain or injury occurs but it is rarely where the underlying problem lives.

Come back tomorrow. We will try to bring this whole thing together, but remember, it will just be a theory for without an exam one cannot prove which issues are true culprits and which are compensations. Remember, what you see is often the compensatory illusion, it is the person moving with the parts that are working and compensating not the parts that are on vacation. See you tomorrow friends !

Shawn and ivo, the gait guys

* note: This is a static assessment dialogue. One cannot, and must not, make clinical decisions from a static assessment. As in all assessments, information is taken in, digested and then MUST be confirmed, denied and/or at the very least, folded into a functional and clinically relevant assessment of the client before the findings are accepted, dismissed and acted upon. As we always say, a gait analysis or static pedograph-type assessment (standing force plate) is never enough to make decisions on treatment to resolve problems and injuries. What is seen and represented on either are the client’s strategies around clinical problems or compensations. Today’s photo and blog post are an exercise in critical clinical thinking to get the juices flowing and to get the observer thinking about the client’s presentation and to help open up the field to questions the observer should be entertaining. The big questions should be, “why do i see this, what could be causing these observances ?”right foot supinated ? or more rear and lateral foot……avoiding pronation ?

The “Standing on Glass” Static Foot/Pedograph Assessment: Part 1

The “Standing on Glass” Static Foot/Pedograph... PART 1
We hope you find this case presentation dialogue interesting.

* note: This is a static assessment dialogue. One cannot, and must not, make clinical decisions from a static assessment. As in all assessments, information is taken in, digested and them MUST be confirmed, denied and/or at the very least, folded into a functional and clinically relevant assessment of the client before the findings are accepted, dismissed and acted upon.

The “Standing on Glass” Static Foot/Pedograph Assessment: Part 1

* note: This is a static assessment dialogue. One cannot, and must not, make clinical decisions from a static assessment. As in all assessments, information is taken in, digested and them MUST be confirmed, denied and/or at the very least, folded into a functional and clinically relevant assessment of the client before the findings are accepted, dismissed and acted upon. As we always say, a gait analysis or pedograph-type assessment is never enough to make decisions on treatment to resolve problems and injuries. What is seen and represented on either are the client’s strategies around clinical problems or compensations. Today’s photo and blog post are an exercise in critical clinical thinking to get the juices flowing and to get the observer thinking about the client’s presentation and to help open up the field to questions the observer should be entertaining. The big questions should be, “why do i see this, what could be causing these observances ?”

* note the right and left sides by the R and L circled in pink.

ORANGE lines: The right foot appears to be shorter, or is it that the left is longer (see the lines and arrows drawing your attention to these differences)? A shorter foot could be represented by a supinated foot (if you raise the arch via the windlass mechanism you will shorten the foot distance between the rear and forefoot). A longer foot could be represented by a more pronated foot. Is that what we have here ? There is no way to know, this is a static presentation of a client standing on glass. What we should remember is that the goal is always to get the pelvis square and level. If an anatomically or functionally short leg is present, the short leg side MAY supinate to raise the mortise and somewhat lengthen the leg. In that same client, they may try to meet the process part way by pronating the other foot to functionally “shorten” that leg. Is that what is happening here ? So, does this client have a shorter right leg ? Longer left ? Do you see a plunking down heavily onto the right foot in gait ? Remember, what you see is their compensation. Perhaps the right foot is supinating, and thus working harder at the bottom end of the limb (via more supination), to make up for a weak right glute failing to eccentrically control the internal spin of the leg during stance phase ? OR, perhaps the left foot is pronating more to drive more internal rotation on the left limb because there is a restricted left internal hip rotation from the top ? Is the compensation top-down or bottom up ? These are all viable possibilities and you must have these things flowing freely through your head during the clinical examination as you rule in/rule out your hands-on findings. Remember, just going by a FMS-type screen to drive prescription exercises from what you see on a movement screen is not going to necessarily fix the problem, it could in fact lead one to drive a deeper compensation pattern. You can be sure that Gray Cook’s turbo charged brain is juggling all of these issues (and more !) when he sees a screen impairment, although we are not speaking for him here.

Remember this critical fact. After an injury or a long standing problem, muscles and motor patterns jobs are to stabilize and manage loads (stability and mobility) for adequate and necessary movement. Injuries leave a mark on the system as a whole because adaptation was necessary during the initial healing phase. This usually spills over during the early movement re-introduction phase, particularly if movement is reintroduced too early or too aggressively. Plasticity is the culprit. Just because the injury has come and gone does not mean that new patterns of skill, endurance, strength (S.E.S -our favorite mnemonic), stability and mobility were not subsequently built onto the apparently trivial remnants of the injury. There is nothing trivial if it is abnormal. The forces must, and will, play out somewhere in the body and this is often where pain or injury occurs but it is rarely where the underlying problem lives.

Come back tomorrow, where we will open your mind into the yellow, pink, blue and lime markings on the photo. Are the hammering toes (lime) on the left a clue ? How about the width of the feet (yellow) ? The posturing differences of the 5th toe to the lateral foot border ? What about the static plantar pressure differences from side to side (blue)? Maybe, just maybe, we can bring a logical clinical assumption together and then a few clinical exam methods to confirm or dis-confirm our working diagnostic assumption. See you tomorrow friends !

Shawn and ivo, the gait guys

Here is the case link.......

https://thegaitguys.tumblr.com/post/99409232289/the-standing-on-glass-static-footpedograph?fbclid=IwAR3gd3d81Gwt3ywAB7BcTwXqST2Z_5nmieODzSb8rJQYBcJFhTs6rS_9auA

Forefoot running, achilles loads & gait retraining

tag/key words: gait, gaitproblems, gaitanalysis, forefootrunning, forefootstrike, achilles, heelstrike, elastography, thegaitguys, microvascularity, rockeredshoes, HOKA, metarocker, gaitretraining,

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Show notes:

Ultrasound elastographic assessment of plantar fascia in runners using rearfoot strike and forefoot strike. Tony Lin-WeiChen et al
https://www.sciencedirect.com/science/article/pii/S0021929019302775
J Sci Med Sport. 2015 Mar;18(2):133-8. doi: 10.1016/j.jsams.2014.02.008. Epub 2014 Feb 14.

Rocker shoes reduce Achilles tendon load in running and walking in patients with chronic Achilles tendinopathy.. Sobhani S et al
https://www.ncbi.nlm.nih.gov/pubmed/24636129/

The increase in muscle force after 4 weeks of strength training is mediated by adaptations in motor unit recruitment and rate coding. Alessandro Del Vecchio et al
https://physoc.onlinelibrary.wiley.com/doi/10.1113/JP277250

Learning new gait patterns is enhanced by specificity of training rather than progression of task difficulty. ChandramouliKrishnan et al
https://www.sciencedirect.com/science/article/pii/S0021929019301927

The microvascular volume of the Achilles tendon is increased in patients with tendinopathy at rest and after a 1-hour treadmill run. Pingel J et al
Am J Sports Med. 2013 Oct;41(10):2400-8. doi: 10.1177/0363546513498988. Epub 2013 Aug 12.
https://www.ncbi.nlm.nih.gov/pubmed/23940204/

*** Our PODcast disclaimer:
This podcast is for general informational purposes only. It does not constitute the practice of medicine, nursing, rehab, treatment, therapy recommendations or anything of the sort. This podcast should not replace proper medical advise that should only be attained through proper medical channels that would entail a full medical and/or biomechanical physical examination and/or appropriate diagnostic testing. No doctor-patient relationship is formed by listening to this podcast or any information gleaned from our writings or social media work.
The use of this information and the materials linked to the podcast is taken at the users own risk. This podcast and the content shared is not intended to replace or be a substitute for appropriate professional medical advise diagnosis or treatment. Users should not disregard or delay obtaining medical advice for any condition they have and should seek the advice and assistance from their providers for any such conditions.

Top end heel raises. The top end might matter.

Thought experiment . . .
If top end posterior compartment (loosely, the calf complex) strength is lacking, then heel rise may not be optimized to transfer body mass forward sufficiently and effectively.
This lack of forward progression, fails to move the body mass sufficiently forward enough to reduce the external moment arms and optimize the internal moment arms to take maximal advantage of the calf complex (I am talking about moment arms between the grounded 1st MTP joint and ankle mortise & ankle mortise and achilles tendon).
These are rough thoughts today gang, letting you inside our heads and how we juggle multiple parameters when we are struggling to solve a client's problems.

In the lower heel rise photo, The body mass does not progress forward enough over the grounded first MTP joint at the big toe (during gait, the heel doesn’t just rise up, the axis of the ankle joint moves both up and forward).
In this case, the foot may not be fully rigid in a supinated position to benefit from joint closed-packed positions. Thus, the foot may be more pliable and one might suppose that if not adequately supinated, they are inadequately still too much relatively pronated. This might put more load into the tibialis posterior and other soft tissue mechanical loading scenarios that are less optimally suited to do this job. Over time, might this lead to pathology? Likely.
Thus, when running on a weaker posterior mechanism (often found unilaterally) the higher up posterior chains might be overburdened, the tendon loads and loading response of the achilles, tibialis posterior, and long flexors will be most likely altered, likely negatively, the naturally occurring foot locking mechanisms might be less optimal than desired, subtalar and forefoot loading might be premature (ie. sesamoid malpositioning for one, as a simple example), etc etc. Loading a foot(the mid and forefoot) into heel rise that is still somewhat pronated creates a different moment arm around the subtalar joint axis (that moves through the 1st metatarsal), than a foot that is more supinated.

Now, put these ideas into the 2 photos from yesterday where one might be loading the forefoot laterally or more medially, and now make the top end strength more in one of those scenarios. Is it any wonder why so many struggle with posteiror mechanism tendonopathies ? There are so many parameters to consider and examine. And, if not examined in great detail, the key lacking parameter can be missed.
Hence, just forcing calf strength loading is too simple a solution, there is a needle in that haystack that upset the client's apple cart, it is the job of the clinician to find it and remedy it.

Today, looking into the research and finding some interesting things that are spurring some thoughts.

Shawn Allen, one of the gait guys

You are mostly likely not getting to your big toe at push-off if you are doing this.

You are mostly likely not getting to your big toe at push-off if you are doing this. And, if you have a painful big toe, you will do it as well. Oh, and Head-over-foot related, yup. Read on . . .

Yes, the cross over gait. Yes, when you are into a cross over gait you are most certainly head over foot. And that is most likely not a good thing.

If you are not closer to stacking the hip over the knee, and knee over the foot (like in the photo "SUI" bib runner) you are not likely getting to much of your big toe at terminal stance loading, when you could be getting more power at push off.
Said another way, if you are attacking the ground with the feet closer together, as if you are running on a line (as in the photo) you are going to be more on the outside of the foot (note the lateral foot contact), show a similar wear/loading pattern as in these shoes, and hardly load the medial foot tripod effectively.
Go ahead, walk around your office or home right now . . . . with a very narrow step width and see how little you can load into the bit toe-medial foot tripod (note how little effective glute engagement you get as well). Then, walk with a wider step width, note the easier more effective big toe-medial tripod loading, and, not the glutes come into play.

Thus, head over foot/cross over gait is foolish for effective gait. You have a big toe, don't you wish to use it ? One has to find that balance between an economical step width that still allows an effective toe off event in walking and running. A very narrow cross over-style gait does not afford us this.
So, should it be any surprise to any of us that someone with pain in the big toe or medial tripod complex will choose a narrow step width to avoid the painful loading ? No, no surprise there at all.
We have been writing about the cross over gait for 10 years, bringing little pieces of research to the forefront to prove our theories on it as the research presents itself. We first brought it to you with our 3 part video series here. Search our blog, type in "cross over gait" into the search box on the site www.thegaitguys.com and get a LARGE coffee before hand, you are going to be reading for several hours.

https://www.youtube.com/watch?v=LG-xLi2m5Rc
https://www.youtube.com/watch?v=WptxNrj2gCo
https://www.youtube.com/watch?v=oJ6ewQ8YUAA

Support for visual gait analysis... with respect to leg length discrepancies

image credit: https://pixabay.com/photos/eye-blue-eyelashes-vision-make-up-691269/

We talk about leg length discrepancies all the time here on the blog and sometimes, how small discrepancies cause changes in peoples biomechanics. The gold standard for measuring a leg length difference is full length lower extremity X ray, but this presents a problem due to the ionizing radiation, accessibility as well as impracticality of X rays every person with a suspected difference.

We have talked about different compensations as to how to get around a leg length discrepancies. Last week we actually did a tell a seminar on this entire subject. Your patient or client needs to “create clearance” for the longer leg side. This can be accomplished in many ways.

The 5 most common strategies (keep in mind there are many more) are:

• lean the torso to the short leg side (essentially hip adduction of the longer side)

• hike the torso on the long leg side

• circumduct the longer lower extremity

• increase plantar flexion of the calf of the short leg side

• increase hip and knee flexion on the longer leg side

And that is exactly what this study found. They looked at kinematics in people with anatomical leg length discrepancies and found that hip adduction as well as increased hip and knee flexion were 2 variables that were consistent in folks with anatomical differences and suggest these variables are a useful screening tool.

Paying attention to how people move and looking for asymmetries. In our opinion, that’s the name of the game : )

Dr Ivo Waerlop, on of The Gait Guys

Zeitoune G, Nadal J, Batista LA, Metsavaht L, Moraes AP, Leporace G.Prediction of mild anatomical leg length discrepancy based on gait kinematics and linear regression model. Gait Posture. 2019 Jan;67:117-121. doi: 10.1016/j.gaitpost.2018.09.027. Epub 2018 Sep 29.

#LLD #leglengthdifference #leglengthinequality #visualgaitanalysis #thegaitguys #gaitanalysis

Pronation anyone? Coupling? Walking Speed? How do they relate?

We have talked many times here on TGG about pronation, supination, overpronation, asymmetrical pronation, and more.

When most people think of pronation, they think of midfoot pronation, or pronation about the subtalar or transverse tarsal joints. Pronation can actually occur about any articulation or bone, but with respect to the foot, we like to think of rearfoot (ie. talo-calcaneal), midfoot (talo-navicular) and forefoot (transverse tarsal). The question is why does this matter?

Pronation, with respect to the foot, is defined as a combination of eversion, abduction and dorsiflexion (see picture attached) which results in flattening of the planter vault encompassing the medial and lateral longitudinal arches. In a normal gait cycle, this begins at initial contact (heel strike) and terminates at midstance, lasting no more than 25% of the gait cycle.

In a perfect biomechanical world, shortly following initial contact with the ground, the calcaneus should evert 4-8 degrees, largely because the body of the calcaneus is lateral to the longitudinal axis of the tibia. This results in plantar flexion, adduction and eversion of the talus on the calcaneus, as it slides anteriorly. At this point, there should be dorsiflexion of the transverse tarsal (calcaneo-cuboid and talo-navicular joints). Due to the tight fit of the ankle mortise and its unique shape, the tibial rotates internally (medially). This translates up the kinetic chain and causes internal rotation of the femur, which causes subsequent nutation of the pelvis and extension of the lumbar spine. This should occur in the lower kinetic chain through the 1st half of stance phase. The sequence should reverse after the midpoint of midstance, causing supination and creating a rigid lever for forward propulsion.

Pronation, along with knee and hip flexion, allow for shock absorption during throughout the 1st half of stance phase. Pronation allows for the calcaneo-cuboid and talo-navicular joint axes to be parallel making the foot into a mobile adaptor so it can contour to irregular surfaces, like our hunter gatherer forefathers used to walk on before we paved the planet. Problems arise when the foot either under pronates (7 degrees valgus results in internal tibial rotation), resulting in poor shock absorption or over pronates (> 8 degrees or remains in pronation for greater than 50% of stance phase).

This paper talks about how foot and ankle pathologies have effects on other articulations in the foot. They looked at stance phase of gait in 14 people without pathology at 3 different walking speeds. they found:

coupling relationships between rear foot inversion and hallux plantar flexion and rear foot eversion with hallux dorsiflexion.... When the rear foot everts (as it does as discussed above) during pronation from initial contact to mid stance , the hallux should be extending AND when the rear foot everts, as it should from mid stance to terminal stance/pre swing, the hallux should be plantar flexing to get the 1st ray down to the ground

medial (internal) rotation of there leg was accompanied by mid foot collapse (read pronation) and lateral (external) rotation with mid foot elevation (read supination).... Because of the shape of the talar dome and shape of the talo calcaneal facet joints, the talus plantar flexes, everts and adducts from initial contact to mid stance, and dorsiflexes, inverts and adducts from mid stance to terminal stance/ pre swing

walking speed significantly influenced these coupling relationships....meaning that the faster we go, the faster these things must happen and the greater degree that the surrounding musculature and associated cortical control mechanisms must act

So, when these relationships are compromised, problems (or more often, compensations) ensue. Think about these relationships and the kinetics and kinematics the next time you are studying someones gait.

Dr Ivo Waerlop, one of The Gait Guys

Dubbeldam R1, Nester C, Nene AV, Hermens HJ, Buurke JH. Kinematic coupling relationships exist between non-adjacent segments of the foot and ankle of healthy subjects.Kinematic coupling relationships exist between non-adjacent segments of the foot and ankle of healthy subjects.Gait Posture. 2013 Feb;37(2):159-64. doi: 10.1016/j.gaitpost.2012.06.033. Epub 2012 Aug 27

cool video on our blog to go with this post:

https://www.thegaitguys.com/thedailyblog/2018/8/7/what-do-you-know-about-pronation-and-supination

#gaitanalysis #thegaitguys #pronation #couplingrelationshipsandgait #pronation

Case Studies in Gait Analysis: Focus on the Short Leg (online video class)

Case Studies in Gait Analysis: Focus on the Short Leg
*link is below

*this is the online Continuing education class we did last week, for those of you who could not get to the Wednesday evening class.
*our entire catalogue of lectures and seminars are all here on this site for CE/CEU

Case Studies in Gait Analysis: Focus on the Short Leg
- Review anatomical vs functional short leg
-Review the kinematics and kinetics of the short leg during the gait cycle
-View and discuss case studies looking at functional and anatomical short legs
-Predict pathomechanics that will arise from a short leg
-Propose remedies for the gait abnormalities seen

Link: https://chirocredit.com/course/Chiropractic_Doctor/Biomechanics_211

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.

More on the scourge of Flip Flops. Riding the inside edge of the sandal. Mystery hunting with Dr. Allen.

Tis the season upon us. Riding the inside edge of the sandal.
You can see it in the photo, the heel is a third of the way off the sandal.

You either have it or have seen it. It is frustrating as hell if you have it. Your heel rides on only half of your flip flop or summer sandals. You do not notice it in shoes, only in sandals, typically ones without a back or back strap. This is because the heel has no controlling factors to keep it confined on the rear of the sandal sole. There is no heel counter on open backed shoes and sandals, the counter keeps the heel central on the back of the footwear. There is a reason this inside edge riding happens to some, but not everyone. It is best you read on, this isn’t as simple as it might seem.

These clients may have restricted ankle rocker (dorsiflexion), restricted hip extension and/or adductor twist (if your reference is the direction the heel is moving towards). I could even make a biomechanical case that a hallux limitus could result in the same scenario. So what happens is that as the heel lifts and adducts it does not rise directly vertically off the sandal, it spins off medially from the “adductor twist” event. This event is largely from a torque effect on the limb from the impaired sagittal mechanics as described above, manifesting at the moment of premature heel rise resulting in an slightly externally rotating limb (adducting heel). The sandal eventually departs the ground after the heel has risen, but the sandal will rise posturing slightly more laterally ( you can clearly see this on the swing leg foot in the air, the sandal remains laterally postured). Thus, on the very next step, the sandal is not entirely reoriented with its rear foot under the heel, and the event repeats itself. The sandal is slightly more lateral at the rear foot, but to the wearer, we believe it is our heel that is more medial because that is the way it appears on the rear of the sandal or flip flop. Optical illusion, kind of… . . a resultant biomechanical illusion is more like it.

You will also see this one all over the map during the winter months in teenagers who swear by their Uggs and other similar footwear, as you can see in the 2nd photo above. This is not an Ugg or flip flop problem though, this is often a biomechanical foot challenge that is not met by a supportive heel counter and may be a product of excessive rear foot eversion as well. This does not translate to a “stable” enough shoe or boot, that is not what this is about. This is about a rearfoot that moves to its biomechanical happy place as a result of poor or unclean limb and foot biomechanics and because the foot wear does not have a firm stable and controlling heel counter. This is not about too much pronation, so do not make that mistake. And orthotic is not the answer. A heel counter is the answer. The heel counter has several functions, it grabs the heel during heel rise so that the shoe goes with the foot, it give the everting rearfoot/heel something to press against, and as we have suggested today, it helps to keep the rearfoot centered over the shoe platform. To be clear however, the necessary overuse and gripping of the long toe flexors to keep flip flops and backless sandals on our feet during the late stance and swing phases of gait, clearly magnifies these biomechanical aberrations that bring on the “half heel on, half heel off” syndrome.

There you have it. Another solution to a mystery in life that plagues millions of folks.

Shawn Allen, the other gait guy

So forget repairing your ACL tear huh?

Soapbox rant today: So forget repairing your ACL tear huh?

Just give it some deep thought before you decide rehab is enough for you. Don't get fully sucked into the non-surgery hype, sometimes there is value and purpose. We are not necessarily saying that we are pro-ACL surgery, but it does have a place when we are talking about a major ligament with many functions beyond articular vector restraint.

*Here is where we see the present problem with the "newer" rehab-only hype for ACL tears . . . . the follow up time frames of the research pieces that suggest that ACLR is sufficient, in our opinion are not long enough into the future (years) to substantiate that secondary instability is not occurring or not a risk. In fact, there are enough articles to substantiate that secondary instability (often deeply rotational) will occur if no ACL repair occurs.

But, other bad things can happen if the joint is not cinched up tightly.
"Increases in TFI (time from injury) are associated with medial meniscal tears, including irreparable medial meniscal tears, medial femoral condyle chondral damage, and early medial tibiofemoral compartment degenerative changes at time of ACLR. These findings highlight the importance of establishing a timely diagnosis and implementing an appropriate treatment plan for patients with ACL injuries. This approach may prevent further instability episodes that place patients at risk of sustaining additional intra-articular injuries in the affected knee. "
*in this study 47.2% were classified as playing competitive or professional sports versus recreational sport

There have been some therapists in the field around the world that have been promoting that ACL surgeries ** are seemingly becoming more and more unnecessary. Their stance seems to be that with hardcore rehab that the knees do just as well, that performance is not lost. Sure, this is possible this or next season, but what about in 2 years? 5 years ? And what will the consequences be then? This article outlines some thoughts.
So, lets just all be careful of the strong points of view we put out there for the consumer. We get their point, but it is foolish to dismiss that the ligament doesn't have a function and is never necessary to replace/repair as this article (and many others report). SECONDARY instability is a real thing, rotational instability in non-ACL repaired** knees is a real thing. Attenuation of secondary joint restraints over time is a real thing, and the cost that comes with those changes. The consequences to the joint structure as secondary instability sneaks in, are a real thing, they are most likely to occur, even if you rehab your client's knee deeply. So be sure that you educate your client, that without their ACL their knee will never be as good, even if you are a champion rehab guru, you are just not that good that you and your rehab can negate all of the rotational vectors of loading in your high level athletes. Time and load will win, just be honest. Just because you do not see consequences tomorrow, just because your top-tier athlete continues to perform this season at top levels without compliant, doesn't mean they will not be present next year. Just be up front with your clients.
And here is another thought to chew on. 24 months ago my Jui-jitsu master Prof Carlos Lemos Jr. tore his ACL. We rehabed and he did well, he even won his 4th world championship without his ACL. But, we had these talks, and he knew that even though he was able to perform at the top level, he knew that the leg was not like the other. He decided 6 weeks ago to have it repaired because we discussed many times the above kinds of long term possibilities. I placed what facts and experiences I have had over 20+ years, the research that is presently out there, and let him decide. He decided that "hope" only goes so far, that he knows he will not be exceptionally as strong on the long term rehab to the degree it was initially performed, and he did not want to risk subsequent internal joint damage that might ensue.
Yes, not everyone needs ACL surgery, especially those who are not highly active or sporting, or the aging/elderly, but we can make a case that just rehabing and dismissing repair is also going to miss some vital points. We are not saying that we are pro-ACL surgery, but it does have a place.
Just educate your client honestly, then let them decide the direction, and do good work.

If anyone wishes to debate here, lets do it. But come at us with 5-10 year post-rehab no-ACL surgery cases with MRI's showing no intra-articular cost. (Good luck with that.) But if you find such unicorns, we definitely want to see them so we can share it and adjust our stance more softly. We want to be as smart and accurate on our rants as possible, it is important.

**corrected/ammended 10:57central time

photo credit: pixabay.com. thank you !

Orthop J Sports Med. 2018 Dec 11;6(12):2325967118813917.
Relationship Between Time to ACL Reconstruction and Presence of Adverse Changes in the Knee at the Time of Reconstruction.
Sommerfeldt M1,2, Goodine T2, Raheem A3, Whittaker J1,4, Otto D

How do humans run faster ?

Runners appear to use two different strategies to increase their speed according to this article we are appreciating by Dorn, Schache and Pandy

In specific observance of the lower limb muscles,
"Humans run faster by increasing a combination of stride length and stride frequency. In slow and medium-paced running, stride length is increased by exerting larger support forces during ground contact, whereas in fast running and sprinting, stride frequency is increased by swinging the legs more rapidly through the air". . . . .
"For speeds up to 7ms–1, the ankle plantarflexors, soleus and gastrocnemius, contributed most significantly to vertical support forces and hence increases in stride length. At speeds greater than 7ms–1, these muscles shortened at relatively high velocities and had less time to generate the forces needed for support. Thus, above 7ms–1, the strategy used to increase running speed shifted to the goal of increasing stride frequency. The hip muscles, primarily the iliopsoas, gluteus maximus and hamstrings, achieved this goal by accelerating the hip and knee joints more vigorously during swing."

Muscular strategy shift in human running: dependence of running speed on hip and ankle muscle performance
Tim W. Dorn, Anthony G. Schache and Marcus G. Pandy*
Department of Mechanical Engineering, University of Melbourne, Victoria 3010, Australia. The Journal of Experimental Biology 215, 1944-1956
© 2012. Published by The Company of Biologists Ltd
doi:10.1242/jeb.064527

More on tendon stiffness

There has been much discussion about tendon stiffness in the last few years. Here is an interesting paper.

Here is a piece of the authors' hypothesis. " If tendons can be overloaded, their mechanical properties should change during exercise. "
The present study measured AT stiffness before and after a marathon.
Here is what they found in this study, "AT stiffness did not change significantly from the pre-race value of 197±62 N mm−1 (mean ± s.d.) to the post-race value of 206±59 N mm−1 (N=12, P=0.312). Oxygen consumption increased after the race by 7±10% (P<0.05) ". This was a small N study, but that leaves room for more large scale studies to see if it holds up.
What remains interesting and head scratching to us is that a tendon has its tension developed by the muscle contracting that is attached to it. So, one would think that a marathon would cause some fatigue in the calf which would change the tension in the achilles. But we are brought to the thought that perhaps stiffness and tension are not the same animals, not even close ?
However, the article mentions this, "A typical training effect, regardless of whether training is plyometric or isometric resistance training, is an increase in AT stiffness (Burgess et al., 2007), although the effect may be invariant to training background as runners and non-runners were found to have similar AT stiffness (Rosager et al., 2002). " Perhaps, what we are talking about however is a "baseline" level of stiffness, that is so fixed that even fatigue does not impact this low level ?
The big question is then, why the AT is so prone to injuries if stiffness remains the big question, and the goal post in rehab restoration?
Here is where these authors leave us, "Thus it may be that running itself does not predispose the AT to injuries. Rather, a combination of a rapid increase in stress, a quick crossover to new sporting activities without a training period, poor technique and/or improper footwear could play a role that has not yet been identified."
A reasonable thought, but leaving us all with more questions than answers it seems.

Additionally, 9 of the 12 subjects, the marathon induced a change in their foot strike technique but they postulated that this could be muscle fatigue related. After all, we cannot forget that there is a whole body attached to this achilles.

Achilles tendon stiffness is unchanged one hour after a marathon
Jussi Peltonen, Neil J. Cronin, Lauri Stenroth, Taija Finni, Janne Avela
Journal of Experimental Biology 2012 215: 3665-3671; doi: 10.1242/jeb.068874

Effects of high loading by eccentric triceps surae training on Achilles tendon properties in humans.

Maximum isometric force had increased by 49% and tendon CSA by 17% !
Tendons can change their cross sectional area, if you load them.

Here I show lateral forefoot loading in a heel raise, and a medial forefoot loading in heel raise. This has to be part of the discovery process outlined below.

Isometrics are useful, they have their place. In a recent podcast to load up here in the future, we discuss the place and time to use isometrics, isotonics, eccentrics and concentrics.
One of the goals in a tendinopathy is to restore the tendon stiffness. Isometrics are a safe way to load the muscle tendon complex without engaging a movement that might have to go through a painful arc of movement. With isometrics here is neurologic over-spill into the painful arc without having to actually go there.
The key seems to be load. More load seems to get most people further along. Remember, the tendon is often problematic because it is inflamed and cannot provide a stiffness across its expanse. Heavy isometric loading seems to be a huge key for most cases. But, we have to say it here, not everyone fits this mold. Some tendons, in some people, will respond better to eccentrics, and strangely enough, some cases like stretching (perhaps because this is a subset of an eccentric it seems or because there is a range of motion issue in the joint that is a subset of the problem). Now the literature suggests that stretching is foolish, but each case is unique all in its own way, and finding what works for a client is their medicine, regardless of what the literature and research says.
Finding the right load for a given tendon and a right frequency of loading and duration of loading is also case by case specific. Part of finding the right loading position is a discovery process as well, as noted in the photos above. Finding the fascicles you want to load, and the ones you do not want to load (painful) can be a challenging discovery process for you and your client. Finding the right slice of the pie to load, and the ones not to load takes experimentation. When it is the achilles complex, finding the safe However, if one is looking for a rough template to build from, brief, often, heavy pain free loads is a good template recipe to start with.

Here, in this Geremia et al article, "ultrasound was used to determine Achilles tendon cross-sectional area (CSA), length and elongation as a function of plantar flexion torque during voluntary plantar flexion."
They discovered that, "At the end of the training program, maximum isometric force had increased by 49% and tendon CSA by 17%, but tendon length, maximal tendon elongation and maximal strain were unchanged. Hence, tendon stiffness had increased by 82%, and so had Young’s modulus, by 86%.

Effects of high loading by eccentric triceps surae training on Achilles tendon properties in humans. Jeam Marcel Geremia, Bruno Manfredini Baroni, Maarten Frank Bobbert, Rodrigo Rico Bini, Fabio Juner Lanferdini, Marco Aurélio Vaz
European Journal of Applied Physiology
August 2018, Volume 118, Issue 8, pp 1725–1736

Look at his guys right leg, the lower leg and foot.

Look at his guys right leg, the lower leg and foot.

This photo was part of an insert in an old Altra shoe box when we got our shoes.

Is that internal tibial torsion, a fixed bony issue that is causing what appears to be the intoe? Or is it a drop of the right hemipelvis into anterior tilt, to try to get more hip extension, which often leads to full leg internal rotation from the hip ? Is it from a weak left hip complex, particularly the abductor players? Remember, internal hip rotation and hip extension can be paired events. Internal hip rotation is a precursor event, in gait, to hip extension. But this is beyond the normal hip extension-internal limb rotation pairing.

There is no way to know except to examine him.
Coaching this out is a mistake until you know what it is.
Prescribing a corrective exercise to attempt to correct it is also a huge mistake without examining the person hands on, and determining whether this is a fixed bony issue, or a functional pattern of choice/power/biomechanics.
It could also be a compensation to another issue, such as I eluded to in a possible weak right lower abdominal interval, allowing the pelvis to tip too far forward.
We have to understand anatomy, biomechanics, compensations and we have to examine our clients.
If a coach tries to train this out, because they do not like the way it looks, it is foolish. Just plain foolish. And if a coach notes this, but does nothing about it, and merely adds training and strength to the "potential" dysfunction, do not be surprised if injury arises. It might not, but adding strength, load and training onto faulty mechanics can have a consequence. There will be those who say, " if it is not a problem, don't fix it". Our response is, sure, that might work, and then again it might not work. Just take responsibility and honest self inventory if that athlete might injure. And learn from it. We are all students.
Do not add strength to dysfunction.

How do you know ? In this case, one has to get educated on osseous torsions and versions, anatomy, biomechanics, to start. Listen, read, learn. We do these things all the time, every day here on The Gait Guys.

Shawn Allen, one of the gait guys

#gait, #gaitproblems, #gaitcompensations, #tibialtorsion, #internaltibialtorsion, #intoed, #running, #sprinting, #thegaitguys, #hipextension, #powerleak

Wild Haggis? Leg length discrepancies on the uphill side? What?

An old Scottish myth has it that the wild haggis (given the fitting taxonomic moniker Haggis scoticus ) is a small fictitious creature (although many folks visiting Scotland believe they are real) that has legs that are longer on one side than the other. There are two varieties: in one the right fore and hind limb are shorter and the other, of course, the left. The asymmetry helps the haggis to circumnavigate the steep mountainsides of its native terrain, but only in a clockwise (if the right legs are short) or counter clockwise (if the left legs are short) direction, so as to not roll down the steep hillside and come to an untimely death; this is purported to be one of the reasons for their near extinction (the other was the introduction of sheep).

The two species coexist peacefully but are unable to interbreed in the wild because in order for the male of one variety to mate with a female of the other, he must turn to face in the same direction as his intended mate, causing him to lose his balance before he can mount her. As a result of this difficulty, differences in leg length among the haggis population are further accentuated, as is there dwindling numbers.

image source: https://en.wikipedia.org/wiki/Wild_haggis#/media/File:Haggis_scoticus.jpg

It’s an amusing concept, but unfortunately there’s a non-mythical human corollary: Leg-length discrepancies (LLDs), which do not discriminate and affect a wide variety of people, including children with cerebral palsy, people who’ve had hip and knee replacements, and those with scoliosis, pelvic obliquity, or certain muscle contractures/dysfunctions.

Haggis is actually a Scottish dish; lungs and liver of a sheep cooked with other ingredients inside its stomach. Yum (Not!) We are not sure why or how the two are related but it does make for an interesting post : )

Learn more about LLD’s and their compensations by joining us Wednesday, April 17th 5 PST, 6MST, 7CST and 8 EST on onlinece.com: Biomechanics 307

Dr Ivo Waerlop, one of The Gait Guys

#haggis #wildhaggis #LLD #leglengthdiscrepancy #leglengthdifference #leglengthinequality #gait #thegaitguys

https://en.wikipedia.org/wiki/Wild_haggis

https://lermagazine.com/article/limb-length-discrepancy-when-how-to-intervene

https://www.atlasobscura.com/articles/what-is-haggis

https://www.thehaggis.com/wild-haggis-all-about-haggis/

https://www.undiscoveredscotland.co.uk/usfeatures/haggis/wildhaggis.ht

the current understanding of how tendons respond to loading, unloading, ageing and injury

A muscle contract, transfers load across the tendon into the attachment to another bone on the other side of a joint, sometimes across 2 joints. There can be a mechanical flaw/injury in the muscle or tendon, or the joint, if inflamed, can neurologically inhibit that muscle-tendon team. The journal abstract has a nice diagram looking at the potential cellular and molecular changes at the tendon interval.
"Here we review the current understanding of how tendons respond to loading, unloading, ageing and injury from cellular, molecular and mechanical points of view. "- S. Peter Magnusson, Michael Kjaer

https://physoc.onlinelibrary.wiley.com/doi/10.1113/JP275450