How did you do on yesterday’s photo of 3 foot strikes ?
Now, look at the women ! Almost pristine ! Still a little evidence of cross over gait in each of them, but pretty darn good ! The feet are falling under the body mass, not good for sprinting, but utilized more in endurance athletes. If you have enough abdominal and hip frontal stabilzers (ie. G. Medius et al) you can play safely with the efficiency factor. If you do not have the strength, you sacrifice efficiency and risk injury at multiple sites in the lower limb. The more cross over you have, the more the foot will strike in inversion (more lateral foot strike), then you much hope you have enough gluteus medius strength at the hip, medial knee stability strength and ankle/arch strength in muscles like the tibialis posterior.
Kara Goucher and Shalane Flanagan, right, shown here leading the 2012 Olympic Trials Marathon,
Photo: Kurt Hoy/Competitor
A visual demonstration of 3 different foot strike patterns. Lets test some of what you have learned here at The Gait Guys over the last few months.
On the readers left, blue shirt Bib 232:
The left leg appears to have all joints stacked at this viewer angle (knee is vertically over the foot, hip is over the knee). What we love here is that the foot profile (look at the black sole of the shoe) is parallel to the ground, it is hard to believe that it won’t strike as such. The medial and lateral aspects of the foot should strike flush and simultaneously. This is a neutral foot and is very likely without valgus or varus forefoot typing. The tibia looks pristine and straight without any torsion, at least from this limited perspective. He also looks to be striding nicely, it seems to appear (albeit this is reaching from this head on view) that the foot will strike below the body mass, this may be because he subtly appears to be leaning forward, again hard to see on this view.
Middle runner, white shirt: We see some problems here. First of all, it appears (and again, this is reaching from a front on view) that this runner is striding out with the foot beyond the body mass and will likely heel strike, he also seems to be in more backward lean that the Blue Bib Man but again hard to tell on a frontal view. We also see that the foot is pitched in inversion (note the outward tip of his foot compared to the man in Blue) quite aggressively which will facilitate a strong excessive lateral heel and/or forefoot strike pattern. You can also see that drawing a line through the length of the long bones (tibia and femur) that they are in alignment, they are even in alignment with the 90 degree perpendicular to the forefoot inverted angulation. This clearly represents our classic “cross over gait” which was first brought to you and the internet by yours truly a few years ago (here on Youtube link). It is easy to see that the projected foot landing will be on a virtual line and thus appear to run on a line or even cross the feet over the line indicating that this client is not stacking the foot, knee and hips vertically and thus challenging the gluteus medius and hip stability into the frontal plane (video link here). This client will be wasting energy and efficiency in the frontal plane (side to side movement) and challenging the core, risking knee tracking issues and excessive foot pronation forces beyond the safe and normal.
Running on the readers right, green shirt #8: There appears to be a strong stance phase leg collapse, the hip is lateral to the foot and the knee is perhaps on its way to medial from a vertical line from the foot. This can be, and often is, from the issues of cross over described in the middle runner above but it can also be simply found in someone who is striking with the foot/knee/hip joints stacked but does not have sufficient gluteus medius strength to keep the pelvis level on the horizon (thus drift laterally). When this happens the downward collapse of the opposite side pelvis is often, but not always, see as a valgus collapse at the knee since the femur is allowed to drift medially from insufficient strength, skill or endurance pairing of the gluteus medius/maximus pairing and the medial quadriceps. This client is likely a cross over victim as well and this would give good reason to the aforementioned. Again, this is all theoretical from a static picture but knowing these patterns like we do, we know these typical patterns of breakdown. This is also suspect because of the foot more positioned under the midline of the body instead of under the knee and hip vertically stacked and the obvious proximity of the knees to one another. These clients often kick or brush the foot or shoe against the stance phase lower leg as they swing the foot through.
Who is going to win this race ? One cannot tell. But if they were the same on all levels of endurance, training, VO2 max and equal on every parameter except what was mentioned above, well then our man in Blue, # 232 would be the most efficient and likely the least injured.
Photo from an Outside Magazine article. We Would reference it, and would be happy to do so, but we cannot find the net article anywhere now. Please send it our way if you happen across it !
Shawn and Ivo, The Gait Guys … . followed in 51 countries and counting.
Yes, we are all twisted: Part 2
Last time we spoke of the 3 major versional changes in the normal course of development of he lower extremity and their importance (if you missed out or forgot, click here). In this post, lets look at the talar neck.
The talus is to the foot, as the lunate is to the hand. It is the only bone that has the entire weight of the body passing through it before being distributed to the foot. It’s motion during pronation should be flexion, adduction and eversion, and in supination: extension, abduction and inversion.
At birth, the angle between the talar neck and talar dome is 30 degrees adduction. This reduces to 18-20 degrees in the adult (see above). During this reduction of angle, the talar head also everts or “twists” laterally (ie promotes pronation), which helps to correct the supination and adducted position of the forefoot in adults present in infants (Saffarian 2011).
Abnormal talar loading and “untwisting” in development (see bottom right picture) has been linked to formation of a Rothbart foot type, also known as metatarsus primus elavatus (Rothbart 2003, 2009,2010. 2012). The 1st metatarsal is elevated and inverted with respect tot eh rest of the foot, with it behaving much like a fore foot varus.
Talar torsion (sometimes called subtalar version) results when there is a 10 degree or greater change in the final position of the talar head. This can cause an adducted position of the forefoot, often mistakenly called “forefoot adductus’, which actually only applies to the metatarsals, and not at all to the talus.
An adducted forefoot provides challenges to gait with many possible compensations. As discussed last time, there are at least 3 reasons we need to understand torsions and versions:
1. They will often alter the progression angle (forgot about progression angles? click here). In talar adduction, there will often be a decreased progression angle of the foot.
2. They affect available ranges of motion of the limb. We remember that the lower leg needs to internally rotate the requisite 4-6 degrees from initial contact to midstance, If it is already fully internally rotated, that range of motion must be created elsewhere. This may result in external rotation of the affected lower limb, excessive pronation through the deformity (if possible), or rolling off the lateral aspect of the foot.
3. They often can effect the coronal plane orientation of the lower limb. In talar torsion, the head of the talus often does not “untwist” appropriately resulting in a functional forefoot varus, with excessive forefoot pronation occurring at terminal stance and pre swing.
There you have it in a nutshell. Talar tosion: Present in 8% of the population (Bleck 1982) and coming to your clinic or a shoe store near you!
All meat and no filler. The Gait Guys!
All material copyright 2013 The Gait Guys/ The Homunculus Group. All rights reserved. Please ask before recycling our stuff!
Treat your children well.
We think Crosby, Stills, Nash and Young had it right…
look at this conclusion: “Shoes affect the gait of children. With shoes, children walk faster by taking longer steps with greater ankle and knee motion and increased tibialis anterior activity. Shoes reduce foot motion and increase the support phases of the gait cycle. During running, shoes reduce swing phase leg speed, attenuate some shock and encourage a rearfoot strike pattern."
let’s break that down a bit:
"Shoes affect the gait of children.” Shoes effect EVERYONE’S gait, not just kids. They alter the ground reactive forces, limit some ranges of motion and thus can promote a compensation or mechanics that you may not have seen previously. Take off one of your shoes. Lift your toes up slightly so you are centered on your tripod. Stand on your “barefoot” leg with your eyes closed. See how long you can stand without faltering. Now repeat that with your shod foot. Some difference, eh? I thought shoes dampened proprioception…They do. But they also give you more support and mechanics that you didn’t have previously, so the foot doesn’t have to work as hard.
“With shoes, children walk faster by taking longer steps with greater ankle and knee motion and increased tibialis anterior activity.”Remember we are talking about kids here. Longer steps because with a shoe we promote heel rocker and because of the added support, more stability (or at least more perceived stability). This means more confidence. Greater knee and ankle motion because of the increased stride length. Greater tibialis anterior activity because of greater dorsiflexion of the foot because of the increased weight (the shoe adds ounces and this muscle must work harder to attenuate the foot as it approached midstance) and increased heel and ankle rocker.
“Shoes reduce foot motion and increase the support phases of the gait cycle.” Shoes constrain the foot and reduce available ranges of motion (yes, even non motion control shoes). Less motion (and thus proprioception) means less feedback to the brain about muscles length and tension (via muscle spindles and golgi tendon organs). The brain will need to have the foot have more contact with the ground to know where it is in space.
“During running, shoes reduce swing phase leg speed,probably due to the increased weight so it takes more to start the process of initial (early) swing
…attenuate some shock we know shoes attenuate at least initial ground reactive forces
…and encourage a rearfoot strike pattern.” most likely due to the cushioning (remember from the recent Kenyan study about barefoot heel strikers? (click here if you need a reminder) They were more likely to heel strike on softer surfaces) AND the increased stride length (which would require more ankle dorsiflexion).
Wow. Shoes really do make the, er….kid.
The Gait Guys. Making it real and increasing your shoe and gait IQ with each post.
J Foot Ankle Res. 2011 Jan 18;4:3. doi: 10.1186/1757-1146-4-3.
Effect of children’s shoes on gait: a systematic review and meta-analysis.
Source
Discipline of Exercise and Sports Science, Faculty of Health Sciences, The University of Sydney, Cumberland Campus, PO Box 170, Lidcombe, 1825, NSW, Australia. cweg6974@uni.sydney.edu.au.
Abstract
BACKGROUND:
The effect of footwear on the gait of children is poorly understood. This systematic review synthesises the evidence of the biomechanical effects of shoes on children during walking and running.
METHODS:
Study inclusion criteria were: barefoot and shod conditions; healthy children aged ≤ 16 years; sample size of n > 1. Novelty footwear was excluded. Studies were located by online database-searching, hand-searching and contact with experts. Two authors selected studies and assessed study methodology using the Quality Index. Meta-analysis of continuous variables for homogeneous studies was undertaken using the inverse variance approach. Significance level was set at P < 0.05. Heterogeneity was measured by I2. Where I2 > 25%, a random-effects model analysis was used and where I2 < 25%, a fixed-effects model was used.
RESULTS:
Eleven studies were included. Sample size ranged from 4-898. Median Quality Index was 20/32 (range 11-27). Five studies randomised shoe order, six studies standardised footwear. Shod walking increased: velocity, step length, step time, base of support, double-support time, stance time, time to toe-off, sagittal tibia-rearfoot range of motion (ROM), sagittal tibia-foot ROM, ankle max-plantarflexion, Ankle ROM, foot lift to max-plantarflexion, ‘subtalar’ rotation ROM, knee sagittal ROM and tibialis anterior activity. Shod walking decreased: cadence, single-support time, ankle max-dorsiflexion, ankle at foot-lift, hallux ROM, arch length change, foot torsion, forefoot supination, forefoot width and midfoot ROM in all planes. Shod running decreased: long axis maximum tibial-acceleration, shock-wave transmission as a ratio of maximum tibial-acceleration, ankle plantarflexion at foot strike, knee angular velocity and tibial swing velocity. No variables increased during shod running.
CONCLUSIONS:
Shoes affect the gait of children. With shoes, children walk faster by taking longer steps with greater ankle and knee motion and increased tibialis anterior activity. Shoes reduce foot motion and increase the support phases of the gait cycle. During running, shoes reduce swing phase leg speed, attenuate some shock and encourage a rearfoot strike pattern. The long-term effect of these changes on growth and development are currently unknown. The impact of footwear on gait should be considered when assessing the paediatric patient and evaluating the effect of shoe or in-shoe interventions.
http://www.ncbi.nlm.nih.gov/pubmed/21244647
all material copyright 2013 The Gait Guys/ The Homunculus Group. All rights reserved. Yea, that means ask before you touch!
Pod #22: Primates, Limb Synchrony & Motor Patterns
/Pod #22: Primates, Limb Synchrony & Motor Patterns
blog link:
http://thegaitguys.libsyn.com/pod-22-primates-limb-synchrony-motor-patterns
iTunes link:
https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138
Show notes:
Neurscience piece:
New Study shows primates move in unison as well.
http://www.labspaces.net/126488/Primates_too_can_move_in_unison
http://thegaitguys.tumblr.com/post/29333686230/have-you-ever-wondered-why-people-who-walk
The synchronization between walking partners is more complex than it seems on the surface. There are two types of synchronization,:
1- in-phase (both person’s right foot move forward at the same time) and
2- out-of-phase synchronization (where the right foot moves forward with the partners left foot).
Ankle-Dorsiflexion Range of Motion and Landing Biomechanics
Chun-Man Fong, Athl Train. 2011 Jan-Feb; 46(1): 5–10.
What comes first ? Muscle weakness, Inhibition (muscle) or a Compensated movement pattern ?
Chronic ankle instability alters central organization of movement.
/Haas CJ, Bishop MD, Doidge D, Wikstrom EA. Am J Sports Med 2010 Apr;38(4):829-34.
Epub 2010 Feb 5. Department of Applied Physiology and Kinesiology,University of Florida, Gainesville, Florida, USA.
This is a recycle article from our “The Gait Guys” blog archive, June 2011. This article focuses on altered proprioception. Proprioception (or kinesthesis) is our ability to orient our body or a body part in space. Poor proprioception can result in balance and coordination difficulties as well as being a risk factor for injury. Think about people with syphillis who lose all afferent information from a joint coming in through the dorsal root ganglia, this ultimately leads to a wide based ataxic gait (due to a loss of position and tactile sense) and joint destruction (due to loss of position sense and lack of pain perception). The same consequences can occur, albeit on a smaller scale, when we have diminished proprioception from a joint or its associated muscle spindles. As you read on, keep the thought in your mind that walking or running are both actually repeated attempts at finding a stable single leg stance, one after the other. Impairment of one single leg stance will affect the involved side locally as well as the contralateral side due to accelerated or abbreviated loading responses coming off of the affected side. Arm swing will also be altered and require compensation.
Proprioception is subserved by both cutaneous receptors in the skin (pacinian coprpuscles, Ruffini endings, etc.), joint mechanoreceptors (types I,II,III and IV) and from muscle spindles (nuclear bag and nuclear chain fibers) . It is both conscious and unconscious and travels in two pathways in the nervous system.
Conscious proprioception arises from the peripheral mechanoreceptors in the skin and joints and travels in the dorsal column system to ultimately end in the thalamus, where the information is relayed to the cortex and cerebellum.
Unconscious proprioception arises from joint mechanoreceptors and muscle spindles and travels in the spino-cerebellar pathways to end in the midline vermis and flocculonodular lobes of the cerebellum. This unconscious information is then relayed from the cerebellum to the red nucleus to the thalamus and back to the cortex, to get integrated with the conscious proprioceptive information and then central program generators (CPG’s). We have spoken about receptors more recently in the Gait Guys podcasts, #19 & 20 and CPG’s in our previous blog post this week if you care to delve more deeply into these topics.
Information from both systems (both separate and combined; the nervous system loves redundancy) is then sent down the spinal cord to effect some response in the periphery. As you can see, there is a constant feed back loop between the proprioceptors, the cerebellum and the cerebral cortex. This is what allow us to be balanced and coordinated in our movements and actions.
Chronic ankle instability is merely a more serious form of dysfunction on the continuum of ankle pathomechanics. It refers to subjects with both coronal and saggital plane stability problems due to altered proprioception. This results in a loss of fine motor coordination of the foot (ie foot intrinsics) and a recruitment of larger motor units about the joint (peroneus longus, flexor and extensor digitorum longus, tibialis posterior and anterior, etc) . This is equivalent to writing a letter with a pencil taped to your wrist, rather than in your fingers.
This study looked at plantar pressure changes (actually it measured the amount of deviation in forward/backward and side to side motions, which are corrective motions by the CNS due to a loss of fine motor control). As expected, they were greater in the group with ankle instability, particularly when they led with that foot (ie the impaired foot). Thus they lacked the skill necessary to perform the task and developed another movement or recruitment pattern to compensate.
This would be an excellent example of restoring function (ie skill) for rehab, rather than just increasing strength. If fine motor control is not mastered 1st and you do not change the central pattern, you are carving a turnip with a chainsaw.
We are…. The Gait Guys
An Alternate View of Crawling and Quadrupedal Motor Patterns: A Correlation to Free Solo Mountain Climbers ?
Quadruped Patterns: Part 1
In the last 3 years, if you have been with us here at The Gait Guys that long, you will have read some articles where we discuss quadrupedal gait (link: Uner Tan Syndrome) and also heard us talk about CPG’s (Central Pattern Generators) which are neural networks that produce rhythmic patterned outputs without sensory feedback. You will have also read many of our articles on arm swing and how they are coordinated with the legs and opposite limb in a strategic fashion during gait and running gaits. Through these articles, we have also eluded to some of the fruitless aspects of focusing solely on retraining arm swing in runners because of the deep neurologic interconnectedness to the lower limbs and to the CPG’s.
IF you are interested in any of these articles we have written please feel free to visit our blog and type in the appropriate words (Uner Tan Syndrome, arm swing, cerebellum, cross over gait) into the Search box on the blog.
Here we briefly look at interconnected arm and leg function in crawling mechanics in a high functioning human (as compared to the Uner Tan Syndrome) in arguably the best solo free climber in the world, Alex Honnold. Here we will talk about the possible neurologic differences in climbers such as Alex as compared to other quadruped species. Primarily, there is suspect of an existing shift in the central pattern generators because of the extraordinary demand on pseudo-quadrupedal gait of climbing because of the demand on the upper limbs and their motorneuron pools to mobilize the organism up the mountain. The interlimb coordination in climbing and crawling biomechanics shares similar features to other quadrupeds, both primate and non-primate, because of similarities in our central pattern generators (CPG’s). New research has however determined that the spaciotemportal patterns of spinal cord activity that helps to mediate and coordinate arm and leg function both centrally, and on a cord mediated level, significantly differ between the quadruped and bipedal gaits. In correlation to climbers such as Alex however, we need to keep it mind that the quadrupedal demands of a climber (vertical) vastly differ in some respects to those of a non-vertical quadrupedal gait such as in primates and those with Uner Tan Syndrome. This is obvious to the observer not only in the difference in quadrupedal “push-pull” that a climber uses and the center-of-mass (COM) differences. To be more specific, a climber keeps the COM within the 4 limbs and close to the same surface plane as the hands and feet (mountain) while a primate, human or Uner Tan person will “tent up” the pelvis and spine from the surface of contact.
What some of the research has determined is that in quadrupeds the lower limbs displayed reduced orientation yet increased ranges of kinematic coordination in alternative patterns such as diagonal and lateral coordination. This was clearly different to the typical kinematics that are employed in upright bipedal locomotion. Furthermore, in skilled mountain climbers, these lateral and diagonal patterns are clearly more developed than in study controls largely due to repeated challenges and subsequent adaptive changes to these lateral and diagonal patterns. What this seems to suggest is that there is a different demand and tax on the CPG’s and cord mediated neuromechanics moving from bipedal to quadrupedal locomotion. There seemed to be both advantages and disadvantages to both locomotion styles. Moving towards a more upright bipedal style of locomotion shows an increase in the lower spine (sacral motor pool) activity because of the increased and different demands on the musculature however at the potential cost to losing some of the skills and advantages of the lateral and diagonal quadrupedal skills. Naturally, different CPG reorganization is necessary moving towards bipedalism because of these different weight bearing demands on the lower limbs but also due to the change from weight bearing upper limbs to more mobile upper limbs free to not only optimize the speed of bipedalism but also to enable the function of carrying objects during locomotion.
The take home seems to suggest that gait retraining is necessary as is the development of proper early crawling and quadruped locomotor patterns. Both will tax different motor pools within the spine and thus different central pattern generators (CPG). A orchestration of both seems to possibly offer the highest rewards and thus not only should crawling be a part of rehab and training but so should forward, lateral and diagonal pattern quadrupedal movements, on varying inclines for optimal benefits. Certainly we need to do more work on this topic, the research is out there, but correlating the quad and bipedal is limited. We will keep you posted. Next week we will follow up on this quadrupedal topic with a video that will blow your mind ! So stay tuned !
Shawn and Ivo
The Gait Guys
Scand J Med Sci Sports. 2011 Oct;21(5):688-99. Idiosyncratic control of the center of mass in expert climbers. Zampagni ML, Brigadoi S, Schena F, Tosi P, Ivanenko YP.
J Neurophysiol. 2012 Jan;107(1):114-25. Features of hand-foot crawling behavior in human adults. Maclellan MJ, Ivanenko YP, Cappellini G, Sylos Labini F, Lacquaniti F.
Yes, we are all twisted: Part 1
Developmentally speaking, that is. Version and Torsion are the words we need to know. There are 3 normal versional changes that take place in the lower extremity development from infant to adult: rotation of the talar head/neck, tibial rotation, and femoral rotation (see above).
So, what is the difference between a torsion and version?
A version is a normal variation in the “twistedness” of a limb (longitudinally speaking) between its proximal and distal portions, representing a normal range of development (see femur above) . An example is the head and neck of the femur has an angle of 8-12 degrees with respect the femoral condyles.
A torsion is the same condition with the amount of twist 1 to 2 standard deviations greater. An example is when the angle of the femoral neck and greater than 15 degrees, the condition of femoral ante torsion exists (see photo above).
There are at least 3 reasons you need to understand about developmental torsions and versions that occur with growth:
- Since they occur in the transverse (horizontal) plane, they affect the progression angle of the foot and thus gait
- They affect available ranges of motion of a limb (ex the femur needs to internally rotate 4-6 degrees for normal gait) and can cause pain and/or gait alterations
- They can affect the coronal (frontal) plane orientation of the lower limb, which can affect gait and shoe choices. A Rothbart foot type with an elevated 1st metatarsal head will often result in a varus (or inverted) position of the forefoot with respect to the rear foot.
In this series, we will explore these 3 major versional changes, one at a time.
The Gait Guys. Bald? Yes! Good looking? You bet! Yes, we are a little more twisted than most folks : )
All material copyright 2013 The Gait Guys/ The Homunculus Group. All rights reserved. Please ask before recycling our stuff!
Podcast #21: You Cannot Beat the Brain
Show Link:http://thegaitguys.libsyn.com/pod-21-beating-the-brain-stretching
iTunes link:
https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138
1. Neuroscience Piece:
Scientists learn more about how inhibitory brain cells get excited
http://www.eurekalert.org/pub_releases/2013-01/ghsu-slm013013.php
2.Stretching and the 49ers
Links
http://www.huffingtonpost.com/estelle-underwood/stretching-exercise_b_2575768.html
http://online.wsj.com/article_email/SB10001424127887324734904578243930799732200-lMyQjAxMTAzMDIwNzEyNDcyWj.html?mod=wsj_valettop_email
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1004076/
The Case of the Apropulsive Cyborg Gait !
Can you identify the deficit in this gait pattern ? Yes, the Cyborg looks like he is pulling his feet out of quicksand with each step, but why ?
Please do not read on until you watch the video a few times……watch the video again and improve your powers of observation and of what you know to be true biomechanically to identify the gait deficit.
This is a recycled blog post from our archives in 2011.
For those in the medical field, you have likely seen this problem……but only unilaterally and that is why it might not be initially familiar. HINT: It could be a lesion of S1 (the first sacral nerve root.)
As I (Dr. Allen) sit at my computer at home I have my desk oriented so that I look out of 4 windows onto a secluded quiet street that many runners in the area have adopted as a safe road to travel. Little do they know what I do for a living let alone that I am spying on them. But, some days I feel like I should hire some high school kid to just hand out my cards at the end of my driveway with an additional little typed up synopsis of their running flaws and list of probable injuries they either currently are milking, or have in the past (or are about to experience !). And so, on my days off I get to work at my desk and look up and see more runners run than I do during a busy day at my clinic. It is both a blessing and a curse. It seems that I just can never get away from this stuff. Heck, I was cooking up dinner the other night and I caught a glimpse of a trailer for a new TV show, and I was hit with seeing yet another interesting gait which prompted yet another call to my partner Ivo. I said to him, “man, you think the celebrity and Gait Guys at the Movies was a neat idea (thanks again Bill !) wait until you hear this idea ! (you will get a sample of that very idea later in the week ! It should be a hit !). Ok, enough babbling. I wanted to create enough dialogue between my initial question so that your wandering eye would not look further down for the gait deficit by curious default.
OK, so what did you see ?
if your answer was……..the Cyborg does not have any ankle plantarflexion whatsoever, you would be right. And without any plantarflexion a person will always be in a forward lean like they are pushing a refrigerator across the floor. Or better yet……like a hockey player who’s skates are laced as such to block out plantarflexion. Plantar flexion, eversion and abduction are all components of pronation; the action which makes the foot a “mobile adapter” rather than the rigid lever of supination we need to propel ourselves forward. This is why they power out the movement to the side and off the inner edge of the blade (in fact, if you look closely at the right ankle of the Cyborg, you will see it flip out into external rotation very quickly just like a NHL pro……by turning out the foot into external rotation he can thus create a push off from the medial foot and big toe, utilizing the FHL to assist in push off.
The left foot (which does not do this), has nothing else to offer.
In this gait, the body mass must lurch forward with an abrupt jerking motion (generated by the rectus abdominus, obliques and hip flexors) and heavy forward arm pump to accelerate the mass forward enough to literally PULL the glued foot off of the ground (PULL rather than PUSH from the gastrocsoleus/gluteal complexes). This would be classified as an APROPULSIVE gait. We have heard some in the coaching world would call this a PULL gait rather than a PUSH gait.
So, I wonder what this cyborg’s foot would look like ? We bet there would be a massive toe long flexor response (and likely hammer toes) in an attempt to find something in the posterior compartment for forward propulsion. Of course this phenomenon would likely not be seen in a broad based S1 nerve root lesion but in a non-ablative non-nerve related problem (ie, a functional problem with the posterior compartment) you could see compensations such as this from the other possible ankle plantarflexor muscles (tibialis posterior, plantaris, flexor digitorum longus).
So, good video case……..hope you enjoyed the case of the Apropulsive Cyborg !
we remain, ……. The Gait Guys……..Shawn and Ivo
Lateral Forefoot loading. Why do we see so many runners laterally strike on the forefoot ?
/This was from a reader on our Facebook PAGE. It was a great observation and a great topic to continue on our dialogue here on the blog and on our last 2 podcasts. We discussed this on the last podcast but we feel that there needs to be further clarification. (FB link) and (Pod link)
I think Runblogger or someone like that showed video clips of footstrike at an elite (or pro) level race…virtually all the elites (or pros) were first contacting the ground on the outside of their forefoot and rolling to the inside.
The Gait Guys response:
For some people, their anatomy “works” or can tolerate the forefoot contact better than others. Remember, the natural walking gait foot progression is heel, lateral forefoot, medial forefoot. The natural running foot strike is under greater debate as you all know if you have been following the materials here on our blog, facebook, twitter and podcasts. Our last two podcasts (#19 and #20) have gone into this in greater depth.
What you likely are seeing (the more lateral forefoot loading pattern) for these elite pro runners in the video you spoke of is normal clean biomechanics (for them), but for many people, you are not seeing that (by the way, we saw plenty of nice squared off forefoot loading responses as well in other pics and videos); rather you are seeing a coping compensation or just simply poor biomechanics that will lead them to injury. The question is when does it become excessive for a person via poor running form choice, forefoot varus foot type or internal tibial torsion etc ? Perhaps a more important question is whether the person has a flexible mid foot and fore foot that will allow the drop of the first metatarsal (medial tripod) to the ground to complete the foot tripod without having to over pronate through the midfoot or forefoot ? That is the key !
And these are valid concerns. Many of people have this, the elites you saw obviously have tolerant anatomy and tolerant biomechanics, for them. For them, they orchestrate all of the parts, perfect or imperfect, into a symphony. This is not as common as many of us would wish. Sure a more (not 100%) squared off forefoot strike is more perfect but not many people have perfect anatomy, in fact we are taught in med school that anatomic variance is the norm. And besides, what is perfect for any given person ? Perfect and clean biomechanics for a given person could arguably be debated as that which enables them to be most efficient without injury long term. Meaning that which may not look pristine but that which acts as such over the long term.
Classically, a brief, controlled, and non-excessive lateral strike may be normal, and with a normal and progressive transition to the medial side of the foot however, many people have a rigidity-flexibility issue between the forefoot and rearfoot (ie. rigid or uncompensated forefoot varus for example) and these people often become patients as runners. This was what we were referring to in podcast #20 which spurred the readers inquiry. These folks cannot adequately, safely and efficiently drop the medial tripod down (1st metatarsal head) without having to so much of the movement more grossly through the midfoot and excessive pronation. Many people try to fix this with shoes or orthotics but it is a bit more complicated than that, although on the surface it seems logical and simple.
Obviously those pros that were viewed do not have these issues, hence why they are pros, meaning optimal mechanics, rarely injured for long combined and with gifted cardio fitness. To be a pro you need all of the pieces, just wanting to run fast or simply training hard is often just not enough to become elite. The pros are a small percent of the population. Many others are not in that category and thus remain at risk injury or become statistics. We have had plenty of elite runners in our offices who had the cardio and the will but not the anatomy and biomechanics to stay out of our offices long term (injury free) to compound the necessary training. Many of these folks were converted to triathletes and have been able to compete at world class levels because we found a way for them to dampen the impact miles on tortured running anatomy.
Sometimes a person’s will is not enough, sometimes you have to have the complete package. And that means competent anatomy and a tolerance system to aberrant biomechanics. In our opinion our dialogue here is critical in runners, unfortunately there are some big gaps from the medical and biomechanics side in many of the dialogues on the internet. But that is were we find our niche, and it is where we are best positioned to help the masses.
Join us weekly on our podcasts, here on our blog, or our other social media sites. Join the Gait Guys brethren !
Shawn and Ivo
The Gait Guys
all material copyright 2013 The Gait Guys/ The Homunculus Group. All rights reserved. Please ask before lifting our stuff!
Podcast #20. Foot Strike Truths Part 2, Exoskeletons & Robots & Haglund's Deformity
/Podcast link:
http://thegaitguys.libsyn.com/pod-20-footstrike-part2-robots-haglund-s-deformi
iTunes link:
https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138
___________________________________
Show notes for Podcast #20.
This is another great podcast. We go deeper into the bowels (and Truth) about foot strike and try to further dispell the myths that are abundant on the topic.
1. Neuroscience Talk:
Brain-machine interfaces could provide “superhuman” abilities, enhancing strength and speed. The reports says these interfaces could also potentially give humans new abilities not previously available. The report also mentions benefits to mobility in the elderly in the form of exoskeletons.
http://www.sciencespacerobots.com/
or
http://www.scribd.com/doc/115962650/Global-Trends-2030-Alternative-Worlds
National Intelligence Council Predicts Superhuman Trend in 2030 Report
J Neuroeng Rehabil. 2013 Jan 21;10(1):3. [Epub ahead of print]
2. Haglund’s Deformity / Syndrome
Everything you wanted to know about this heel problem, and more !
3. The Problems with Footstrike and Foot types, Part 2.
Research based truth behind foot stress fractures: Foot Landing and Loading Pathomechanics.
We talk about this journal article and the implications of foot landing mechanics and metatarsal stress fractures in the literature during Podcast # S1-E3 (Season1-Episode3) in case you want to hear what else we had to say on this topic.
http://www.elitetrack.com/blogs/details/7047/
Computer simulation of stress distribution in the metatarsals at different inversion landing angles using the finite element method
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2903174/
From the Expert: Danny Abshire Talks Foot Placement
http://blog.newtonrunning.com/blog/bid/262036/From-the-Expert-Danny-Abshire-Talks-Foot-Placement
Though you weigh less when naked, it doesn’t mean you are more efficient…
“Running barefoot offers no metabolic advantage over running in lightweight, cushioned shoes.”
This study looked at VO2 max (ie. the bodies ability to utilize oxygen, or more precisely, the maximal oxygen uptake or the maximum volume of oxygen that can be utilized in one minute during maximal or exhaustive exercise. It is measured as milliliters of oxygen used in one minute per kilogram of body weight ).
The study found that VO2 increased as weight was added to the foot, whether or not ehy were wearing shoes AND there was not significant difference.
“V˙O(2) increased by approximately 1% for each 100 g added per foot, whether barefoot or shod (P < 0.001). However, barefoot and shod running did not significantly differ in V˙O(2) or metabolic power. A consequence of these two findings was that for footwear conditions of equal mass, shod running had ∼3%-4% lower V˙O(2) and metabolic power demand than barefoot running (P < 0.05).”
An interesting finding was that VO2 was actually 3-4% less for shod running than barefoot, indicating increased metabolic efficiency (albeit small) for shoes.
Why? Our theory is increased biomechanical efficiency with shoes. Shoes, creating less pronatory force and accessory motion (due to cushioning and constraints of the shoe; ie it takes some of the complexity out of the motion) created a more rigid lever with better force transduction.
The Gait Guys. Asking the hard questions and giving you the facts with each post.
Med Sci Sports Exerc. 2012 Aug;44(8):1519-25. doi: 10.1249/MSS.0b013e3182514a88.
Metabolic cost of running barefoot versus shod: is lighter better?
Source
Locomotion Lab, Department of Integrative Physiology, University of Colorado, Boulder, CO, USA. jason.franz@colorado.edu
Abstract
PURPOSE:
Based on mass alone, one might intuit that running barefoot would exact a lower metabolic cost than running in shoes. Numerous studies have shown that adding mass to shoes increases submaximal oxygen uptake (V˙O(2)) by approximately 1% per 100 g per shoe. However, only two of the seven studies on the topic have found a statistically significant difference in V˙O(2) between barefoot and shod running. The lack of difference found in these studies suggests that factors other than shoe mass (e.g., barefoot running experience, foot strike pattern, shoe construction) may play important roles in determining the metabolic cost of barefoot versus shod running. Our goal was to quantify the metabolic effects of adding mass to the feet and compare oxygen uptake and metabolic power during barefoot versus shod running while controlling for barefoot running experience, foot strike pattern, and footwear.
METHODS:
Twelve males with substantial barefoot running experience ran at 3.35 m·s with a midfoot strike pattern on a motorized treadmill, both barefoot and in lightweight cushioned shoes (∼150 g per shoe). In additional trials, we attached small lead strips to each foot/shoe (∼150, ∼300, and ∼450 g). For each condition, we measured the subjects’ rates of oxygen consumption and carbon dioxide production and calculated metabolic power.
RESULTS:
V˙O(2) increased by approximately 1% for each 100 g added per foot, whether barefoot or shod (P < 0.001). However, barefoot and shod running did not significantly differ in V˙O(2) or metabolic power. A consequence of these two findings was that for footwear conditions of equal mass, shod running had ∼3%-4% lower V˙O(2) and metabolic power demand than barefoot running (P < 0.05).
CONCLUSIONS:
Running barefoot offers no metabolic advantage over running in lightweight, cushioned shoes.
PMID: 22367745
http://www.ncbi.nlm.nih.gov/pubmed/22367745
all material copyright 2013 The Gait Guys/The Homunculus Group.
The debate continues. More support for mid and forefoot strikers.…
“Forefoot and midfoot strikers had significantly shorter ground contact times than heel strikers. Forefoot and midfoot strikers had significantly faster average race speed than heel strikers.”
We are not saying “better”, but according to this study “faster”!
What is the ideal? We wish we knew…Biomechanics seem to point to less impact is better, but what is actually best for the individual is probably due to genetics, training, practice, running surface and that individuals neuromuscular competence and ability to compensate.
The Gait Guys. bringing you the facts, even if you or we don’t like them…
J Sports Sci. 2012;30(12):1275-83. doi: 10.1080/02640414.2012.707326. Epub 2012 Aug 2.
Foot strike patterns and ground contact times during high-calibre middle-distance races.
Source
Department of Sport and Exercise Sciences, School of Life Sciences, Northumbria University, Newcastle-upon-Tyne NE1 8ST, UK. phil.hayes@northumbria.ac.uk
Abstract
The aims of this study were to examine ground contact characteristics, their relationship with race performance, and the time course of any changes in ground contact time during competitive 800 m and 1500 m races. Twenty-two seeded, single-sex middle-distance races totaling 181 runners were filmed at a competitive athletics meeting. Races were filmed at 100 Hz. Ground contact time was recorded one step for each athlete, on each lap of their race. Forefoot and midfoot strikers had significantly shorter ground contact times than heel strikers. Forefoot and midfoot strikers had significantly faster average race speed than heel strikers. There were strong large correlations between ground contact time and average race speed for the women’s events and men’s 1500 m (r = -0.521 to -0.623; P < 0.05), whereas the men’s 800 m displayed only a moderate relationship (r = -0.361; P = 0.002). For each event, ground contact time for the first lap was significantly shorter than for the last lap, which might reflect runners becoming fatigued.
PMID:22857152[PubMed - indexed for MEDLINE]
Podcast #19: Of Fish, Footstrike and Facts about Running
/Podcast #19: Of Fish, Footstrike and Facts about Running
Permalink URL
http://thegaitguys.libsyn.com/pod-19-fish-foot-strike-facts
itunes link:
https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138
Today’s Topics:
1. Neuroscience piece: Fish and limb buds and becoming bipedal.
Link: http://www.sciencenews.org/view/generic/id/346972/description/News_in_brief_Fins_to_limbs_with_flip_of_genetic_switch
2. Joint Replacement: new research and updates
http://www.jospt.org/issues/articleID.2815,type.1/article_detail.asp
3. Footstrike 101: How Should Your Foot Hit The Ground?
Support for a midfoot strike?
“Running with a midfoot strike pattern resulted in a significant increase in gastrocnemius lateralis pre-activation (208 ± 97.4 %, P < 0.05) and in a significant decrease in tibialis anterior EMG activity (56.2 ± 15.5 %, P < 0.05) averaged over the entire stride cycle. The acute attenuation of foot-ground impact seems to be mostly related to the use of a midfoot strike pattern and to a higher pre-activation of the gastrocnemius lateralis. ”
Do these results surprise you? They didn’t really surprise us.
The lateral head of the gastroc is a midstance to preswing stabilizer and works synergistic with the medial head, with the medial head firing earlier. Sutherland talks about these muscles not being propulsive in nature, but rather maintainers of forward progression, step length and gait symmetry. Thinking this through in a closed chain (foot up) fashion, this would counter the inversion moment created by the medial gastroc for supination in the second half of contact phase. If the foot is already partially supinated (as we believe it would be in a midfoot strike), it would have to pre activate.
A decrease in tibialis anterior activity? Sure. If the foot is striking more parallel to the ground, the anterior compartment (including the tibialis anterior, extensor hallucis longus, and extensor digitorum longus) would not have to eccentrically contract to decelerate the lowering of the foot to the ground.
Better? Maybe, maybe not. We are seeing more and more literature about foot strike (if you missed our last few posts, click here, here, here and here), We still maintain that you need a competent lower kinetic chain, including the foot and an intact nervous system to drive the boat.
We remain, handsome, bald and nerdy…Ivo and Shawn
Eur J Appl Physiol. 2012 Aug 9. [Epub ahead of print]
Impact reduction during running: efficiency of simple acute interventions in recreational runners.
Source
University of Lyon, 42023, Saint-Etienne, France.
Abstract
Running-related stress fractures have been associated with the overall impact intensity, which has recently been described through the loading rate (LR). Our purpose was to evaluate the effects of four acute interventions with specific focus on LR: wearing racing shoes (RACE), increasing step frequency by 10 % (FREQ), adopting a midfoot strike pattern (MIDFOOT) and combining these three interventions (COMBI). Nine rearfoot-strike subjects performed five 5-min trials during which running kinetics, kinematics and spring-mass behavior were measured for ten consecutive steps on an instrumented treadmill. Electromyographic activity of gastrocnemius lateralis, tibialis anterior, biceps femoris and vastus lateralis muscles was quantified over different phases of the stride cycle. LR was significantly and similarly reduced in MIDFOOT (37.4 ± 7.20 BW s(-1), -56.9 ± 50.0 %) and COMBI (36.8 ± 7.15 BW s(-1), -55.6 ± 29.2 %) conditions compared to NORM (56.3 ± 11.5 BW s(-1), both P < 0.001). RACE (51.1 ± 9.81 BW s(-1)) and FREQ (52.7 ± 11.0 BW s(-1)) conditions had no significant effects on LR. Running with a midfoot strike pattern resulted in a significant increase in gastrocnemius lateralis pre-activation (208 ± 97.4 %, P < 0.05) and in a significant decrease in tibialis anterior EMG activity (56.2 ± 15.5 %, P < 0.05) averaged over the entire stride cycle. The acute attenuation of foot-ground impact seems to be mostly related to the use of a midfoot strike pattern and to a higher pre-activation of the gastrocnemius lateralis. Further studies are needed to test these results in prolonged running exercises and in the long term.
PMID:22875194 [PubMed - as supplied by publisher]
All material copyright 2013 The Gait Guys/The Homunculus Group, yada, yada, yada…
Gait Guys, can I wear my racing flats during regular weekly base runs ?
/Perhaps the better question is “should you wear your racing flats for regular base building runs ?" Most injuries are based on a volume of impact miles across anatomy structures that are not appropriately protected or which have been encouraged into biomechanically challenged positions because of surrounding weakness or functional asymmetry.
In previous blog posts we have talked about the theory that more EVA foam is not always better and supported these ideas with research. However, the pendulum can swing to the opposite as well. It is also plausible that a tipping point of less foam also increases risk because of a lack of shock attenuation. The results of the study below demonstrated significant differences in peak pressure, maximum force, and contact area between the two shoe conditions of racing flat and regular training shoes (see study for specifics). There was a significantly higher maximum force measured in the lateral midfoot in the racing flats while an increased maximum force was observed beneath the rearfoot in the training shoe,
What the study did not go into was the foot type and the running form from what we could tell. Heck, it is even possible that the small "n” of the study could have included a bolus of cross over runners with forefoot varus for all we know. the study did not delve that deep. We have all learned that often it is not what you do but how you do it and additionally, although not entirely pertinent here, that what we see is often not the problem (translation: just because the peak pressures measured high in an area does not necessarily mean that the adjacent anatomical structure to the peak pressure will suffer the impact and trauma of said pressures. This is a dynamic load sharing organism, where things break down is rarely where the problem exists)
Bottom line from our standpoint, and this does not hold true for everyone but it is a fairly safe statement, if your foot type is not pristine and your running form could stand some perfecting then perhaps running flats for anything than race day is not the most sane and cerebral decision. This may be especially true if you are milking some subtle injuries or asymmetries that speak to you from time to time on a run. But to each his own. Human’s are inherently risk takers and subject to cognitive dissonance, especially when things are going well. And who knows, runners may fall even deeper into this profile for all we know.
Here is the study for your perusal.
If you want to get better at this game of assessment, shoe fitting and foot type matching you might want to consider our National Shoe Fit Program. Email us at thegaitguys@gmail.com if you want us to send you some information on our program.
Shawn and Ivo, The Gait Guys
Differences in plantar loading between training shoes and racing flats at a self-selected running speed.
Wiegerinck JI et al. Gait Posture. 2009 Apr;29(3):514-9. Epub 2009 Jan 14.
Summarized Abstract:
The purpose of this study was to examine the difference in plantar loading between two different running shoe types. We hypothesized that a higher maximum force, peak pressure, and contact area would exist beneath the entire foot while running in a racing flat when compared to a training shoe. Peak pressure, maximum force, and contact area beneath eight different anatomical regions of the foot as well as beneath the total foot were obtained. The results of this study demonstrated a significant difference between training shoes and racing flats in terms of peak pressure, maximum force, and contact area. The significant differences measured between the two shoes can be of importance when examining the influence of shoe type on the occurrence of stress fractures in runners.
