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!

The Gait Guys talk more about the myths and truths of foot strike. Join us on this youtube video today.

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

A very cool video comprises this post today. It exemplifies the 3 systems that keep us upright in the gravitational plane: vision, the vestibular system and proprioception (we did a cool post on some of this a while ago here and here)

Enjoy, and have a great weekend!

Ivo and Shawn

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?

Franz JR, Wierzbinski CM, Kram R.

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.

Hayes P, Caplan N.

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]

http://www.ncbi.nlm.nih.gov/pubmed/22857152

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?

http://running.competitor.com/2012/12/injuries/footstrike-101-how-should-your-foot-hit-the-ground_63548

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.

Giandolini M, Arnal PJ, Millet GY, Peyrot N, Samozino P, Dubois B, Morin JB.

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.

Looks like Newbies are heel strikers

“Nearly all novice runners utilize a rearfoot strike when taking up running in a conventional running shoe. Hereby, the footstrike patterns among novice runners deviate from footstrike patterns among elite and sub-elite runners.”

please take some time to explore the links we put in, as they are germane to the post

The question begs, “Why?”

• do they believe running is merely an extension of walking, and just “speed up” the process?
• are they afraid of going too fast and are using the heel strike to “brake”?
• do they learn to strike differently with more experience? at least one paper eludes to “yes”
• is it “more comfortable” as this paper says it may be?
• If there is a rear foot strike, the foot is poised to be able to pronate to a greater degree. This theoretically means it (ie, the foot) can absorb more shock through this mechanism, although this seemingly contradicts the Lieberman study

This paper certainly had a nice cohort size (> 900 runners) so we can state, at least for this group, that this is not by chance.  When there is a fore foot strike, the foot is more supinated and makes a seemingly “rigid lever”, does this mean there is less shock (perceived or actual) with this foot posture?

Lots of questions. This is only 1 part of the puzzle.

The Gait Guys. Sifting through the literature and giving you the beef

Gait Posture. 2012 Dec 29. pii: S0966-6362(12)00448-1. doi: 10.1016/j.gaitpost.2012.11.022. [Epub ahead of print]

Footstrike patterns among novice runners wearing a conventional, neutral running shoe.

Bertelsen ML, Jensen JF, Nielsen MH, Nielsen RO, Rasmussen S.

Aarhus University Hospital, Aalborg Hospital, Orthopaedic Surgery Research Unit, Science and Innovation Center, Aalborg DK-9000, Denmark. Electronic address: miclejber@gmail.com.

Abstract

INTRODUCTION:

It has been suggested that striking on the midfoot or forefoot, rather than the rearfoot, may lessen injury risk in the feet and lower limb. In previous studies, a disparity in distribution in footstrike patterns was found among elite-, sub-elite, and recreational runners.

PURPOSE:

The purpose of this study was to investigate the footstrike patterns among novice runners.

METHODS:

All runners were equipped with the same conventional running shoe. Participants were video filmed at 300 frames per second and the footstrike patterns were evaluated by two observers. The footstrike was classified as rearfoot, midfoot, forefoot, or asymmetrical.

RESULTS:

A total of 903 persons were evaluated. The percentages of rearfoot-, midfoot-, forefoot-, and asymmetrical footstrike among men were 96.9%, 0.4%, 0.9%, and 1.8%, respectively. Among women the percentages were 99.3%, 0%, 0%, and 0.7%, respectively.

CONCLUSION:

Nearly all novice runners utilize a rearfoot strike when taking up running in a conventional running shoe. Hereby, the footstrike patterns among novice runners deviate from footstrike patterns among elite and sub-elite runners.

Copyright © 2012 Elsevier B.V. All rights reserved.

PMID: 23280125 [PubMed - as supplied by publisher]

all material copyright 2013 The Gait Guys/The Homunculus group. Please don’t lift our stuff without asking and giving credit.

A return to "the solitary externally rotated foot"

Dear Gait Guys:

I compete at a high level in a variety of sports, but over the past five years I have developed tremendous discomfort and occasional pain.  I have talked to orthopedic surgeons and physical therapists with no results.  I had MRIs done on my hip, shoulder and knee (my problem areas) but they came back clean.  Finally I saw your article on the “solitary externally rotated foot”.  My symptoms of the outward turned foot, weak glutes, uncomfortable patellar tracking and limited hip rotation.  Also, my shoulder seems to be externally rotated as well which causes pain and inhibits my pec major from firing.  You guys are the only ones who have come close to figuring out my problems and are the only refuge from my frustration.  How can I fix this?  Are their some good exersizes and why have no physical therapists heard of the “kickstand effect”?  

Thank you so much,

(name withheld, NW)

_____

Dear NW

We loosely used the name “kickstand Effect” to describe in part what the foot is acting as. By turning out the foot into the frontal plane you are engaging more of the frontal plane for stability, stability which you likely do not have in the frontal plane by the primary pattern stabilizer(s) and or synergists.

Without more clinical hands on exam we are at a loss to help you, remember a clean objective examination followed by a solid screen of movement patterns is always paramount, something we just cannot obtain over the internet.  We would love to give theories and exercises, but then we would just be shooting from the hip and and in a case like this more compensations (if we give the wrong recommendations) is not what you need at your level and level of frustration.  But, we wanted to share this kind readers case and attach the original article they were referring to. After all, it has been more than a year since we wrote it.

Here is the link:  “THE SOLITARY EXTERNALLY ROTATED FOOT”

http://thegaitguys.tumblr.com/post/14262793786/gait-problem-the-solitary-externally-rotated

SHAWN AND IVO

the gait guys

Functional Ankle Instability and the Peroneals 

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

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

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

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

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

Take home message?

Keep the peroneals strong with lots of balance work!

The Gait Guys: bringing you the meat, without the filler!                                                                         

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

Peroneal activation deficits in persons with functional ankle instability.

Palmieri-Smith RM, Hopkins JT, Brown TN.

Source

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

Abstract

BACKGROUND:

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

HYPOTHESIS:

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

STUDY DESIGN:

Cross-sectional study; Level of evidence, 3.

METHODS:

Twenty-one (18 female, 3 male) patients with unilateral FAI and 21 (18 female, 3 male) uninjured, matched controls participated in this study. Peroneal maximum H-reflexes and M-waves were recorded bilaterally to establish the presence or absence of AMI, while electromyography (EMG) recorded as patients underwent a sudden ankle inversion perturbation during walking was used to quantify dynamic activation. The H:M ratio and average EMG amplitudes were calculated and used in data analyses. Two-way analyses of variance were used to compare limbs and groups. A regression analysis was conducted to examine the association between the H:M ratio and the EMG amplitudes.

RESULTS:

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

CONCLUSION:

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

all material (except for the study); copyright 2013 The Gait Guys/ The Homunculus Group. All rights reserved. Please ask before you lift our stuff. If you are nice and give us credit, we will probably let you use it!

New Study Finds Group of Heel Striking Barefoot Kenyan Runners.

Not all that is barefoot is necessarily forefoot…

You may have seen our tweet yesterday and have read this article. Or maybe, because you are a foot geek, you have seen it already.

Here’s the summary: “Jan. 9, 2013 — A recently published paper by two George Washington University researchers shows that the running foot strike patterns vary among habitually barefoot people in Kenya due to speed and other factors such as running habits and the hardness of the ground. These results are counter to the belief that barefoot people prefer one specific style of running.”

The study reported a 72 percent rearfoot landing when running barefoot at endurance pace speeds supporting the notion that speed affects landing choice (faster speeds transitioned  the runners into more midfoot / forefoot landing).  Lieberman’s Harvard study which brought much of the forefoot strike principle to the western world was often based off of sub 5 mile paced runs.

It raises the question “ If barefoot IS better, and forefoot impact IS BETTER, then, what gives?”

We think the better response is:

• there are many variables (genetics, surface, speed, etc) that can influence foot strike patterns and this paper exemplifies that.
• Fore foot striking in runners does lessen impact forces.
• Forefoot striking does appear to accentuate any forefoot abnormality (ie: varus/valgus) that may be present (something we will continue to say until someone proves it otherwise).
• forefoot striking loads the posterior compartment of the lower leg (tricep surae (gastroc soleus complex)) to a greater degree

We like a mid foot strike, not because it is the middle road, but because it supports the notion in distance running that the entire foot tripod (which is more stable) engages the ground reducing solitary forefoot and rearfoot loading issues which each have their risks and challenges and allows for a more stable contact point for the body to negotiate over.  We have pounded sand on forefoot types, and the inherent risks of forefoot strike running with each of them, from our inception.  But, when it comes to midfoot strike there doesn’t appear to be much, if any literature out there to support our opinion.  Maybe now that the forefoot and rearfoot studies are out there maybe someone will find a tribe of midfoot strikers to support our rants.

We think the key is not necessarily strike position, but rather where the foot is hitting the ground relative to the body AND MORE IMPORTANTLY, having a competent foot and lower kinetic chain and core, along with the body’s ABILITY to absorb or attenuate those forces, no matter where the foot is striking the ground.

This is no doubt the 1st in a series of papers looking at this. It will be interesting to see where it goes from here.

Ivo and Shawn…  The Gait Guys

here is the link: http://www.sciencedaily.com/releases/2013/01/130109185856.htm

all material copyright 2013 The Homunculus Group/ The Gait Guys. Please ask to use our stuff and reference it appropriately. We know a guy named BamBam who helps people play nice.

Gait Guys, What is the truth when it comes time to buying/rotating new shoes ?

A few moons ago an awesome Facebook reader asked us about changing shoes and the validity of the “press test”.  Here was Eve’s link to the press test and here is what it said:

 Do the Press Test

“To determine if the midsoles of your shoes are compressed and are no longer providing cushioning, do the press test. Using your thumb, push on the outsole upward into the midsole. With new shoes, it should be easy to see the midsole compress into lines or wrinkles. As the shoe wears down, the midsole compresses less with the same amount of pressure. When the midsole shows heavy compression lines and the press test reveals a minimal amount of compression, there is little or no cushioning left.”

There is a valid point to this test, but it might be considered too rudimentary by many purists.  But most purists rarely can offer us a better solution.  Here is the issue, EVA foam has a lifespan in terms of maintaining its initial shock absorption. EVA foam cells compress and deform over time, most foam in this world does whether it is your Tempurpedic mattress, the foam base for your rugs or your car seat. And with areas of greater wear and compression the foam accelerates its deformation. This is why certain areas of your car seats, your rugs and your bed get softer.  The same thing goes with your shoes. But they really do not get softer, the areas get compressed and the foam changes its density and its integrity. It no longer performs.  Resistance, compressibility and resilience changes.  This is the problem with shoe foam as well, no matter what foam a company is using.  However, the bigger problem if you really think about it is that the foot type you have and the biomechanics (good or bad) that you drive your foam into will be the direction future foot loadings deviate into.  Can this be good ? Rarely. Can this be bad ? Usually.  EVA simply has a given number of cycles, and that number is variable with many factors in place such as weight, running form, foot strike, foot type, weathering of the foam, wet foam, dry foam, outer sole glue, foot bed components and attachment, number of miles.  So, degrading shoe foam is a fact of life for a walker or runner. 

The “press test” gives the user some idea of how much the foam is compressed and how much resilience it has left. But it is a test limited very much by the subjective assessment.  We wouldn’t hold a torch to the test and make it a solitary assessment factor, in fact we rarely do it ourselves. But every little test and assessment has some perks and information that can be gleaned from it.

For the record, we like to play it cautious because injuries cost money and time to a runner. So we error on the side of caution always and go for lower numbers for the life span of shoes.  Each shoe is different and we will  not leave you with actual numbers here because the algorithm gets a bit large and convoluted but the bottom line is that cheaper shoes usually use cheaper materials and more expensive shoes usually use better materials (yes, this does not always line up as truth, we know this).  But shoes like Newtons and Altras from our experience seem to survive the trials of running a bit better (at least in our athletes) and so we allow more miles in them.  But for those looking for some harder numbers here are our loose rules:

400-500 miles per pair of shoes.  At 200 miles begin a second pair of shoes and start alternating the shoes every run (old shoe one day, next day use the new shoe).  This will reduce the successive days in a shoe in which the foam is driving deeper and deeper into deformity and thus you are only a day away from a reprieve from the deforming shoe. This will reduce injury risk.  This will also give you a dry shoe on a run the day after a shoe got soaked or caked with mud.  Water and mud add shoe weight and change biomechanics. Once the older shoe his the end lifespan mark you have the second shoe at 200-250 and you are ready for a new shoe. So you are never in a shoe until its death, when it is completely deformed and driving pathomechanics and possible injury only to the very next day step into a new shoe with entirely different (albeit neutral and unbiased) mechanics in the foam.  Injuries occur much of the time with change. Be smarter with your shoe rotation and reduce change.

VITAL NOTE:

Running and walking use different biomechanics and loading styles. Walking has heel strike as a norm, running for the most part shouldn’t include heavy or any heel strike depending on the athlete and who’s “pulpit of running form” that athlete chooses to pray at the foot of. Like religion, there is no one right way …  we each need to find what is best for us. And thus, since running and walking biomechanics are so different you should keep your running shoes for running and have another pair for walking and your other workouts.  Remember though, running shoes are build mostly for sagittal (forward) movement and not for lateral sports. This is why you should never, never ever, use your running shoes for tennis, racquet ball, basketball or many forms of cross fit.  Get a court shoe that is build for lateral movement. Not only will the shoe last longer but it is built on a platform that is more suited for such activity.

Shawn and Ivo

The Gait Guys…….

A little neuro, anyone?

Welcome to Monday, and yes, it is a NEURO day. In fact, if you got up this morning, you too are having a NEURO day. Dr Allen thinks it’s all about the ORTHOPEDICS, but without NEURO, there would not be any orthopedics : )

A dialogue from one of our avid readers, Dr. Ryan.

Dr. Ryan: Hey Ivo,

I just read this article on Mercola’s site which is an interview with Dr. Craig Buhler who does muscle activation techniques.  Can you check this for accuracy?  This must be a mistake b/c I always thought spindle activation will facilitate the muscle to contract.  Also, I always wondered why the O/I attachment points are tender in muscles that are inhibited.  Does his description sound right to you.  If not, do you have a better explanation?

“Your muscle system and nervous system relate to each other from within tiny muscle fibers called spindle cells, which monitor stretch. If your muscle is overloaded too rapidly, the spindle cells will temporarily inhibit the muscle. The next time you contract the muscle, it will fire again. Similarly, cells within your tendons called Golgi tendon organs also measure and monitor stretch. If your tendon is stretched too rapidly or exceeds its integrity, the Golgi tendon organs will temporarily inhibit the muscle. But the next time the muscle fires, it will again fire appropriately.

"But there’s a fail-safe system," Dr. Buhler explains. "It’s where the tendon attaches into the periosteum of the bone and the little fibers there are called Sharpey’s fibers. Those fibers are loaded with little receptors that monitor tension. And if the integrity of those fibers are exceeded, they inhibit the muscle, just like a circuit breaker would inhibit an electrical circuit.

Once that happens, the muscle will still fire under passive range of motion. But if you load the muscle, it gives way. If you continue to load the muscle, your body creates pain at the attachment points to protect you. What the central nervous system does at that point is compute an adaptive strategy by throwing stress into the muscle next to it. Other tissues begin to take on more of the load for the muscle that’s been injured.”

Here is a link to the entire article if you want to check it out:

http://fitness.mercola.com/sites/fitness/archive/2013/01/04/advanced-muscle-integration-technique.aspx?e_cid=20130104_DNL_art_1"

Dr Ivo: Thanks Dr. Ryan.

Spindles monitor length and GTO’s monitor tension. My understanding is spindles, when activated, stimulate the alpha motor neuron(at the cord) and cause contraction of that muscle or motor unit. GTO’s, when activated, cause inhibition of the muscle they are associated with. I am not aware of them being inhibitory, only GTO’s. They are believed to be GABAnergic synapses. The impulse (at least in cats) can be smaller or inhibited if the muscle is held in contraction for an extended period of time (see attached)

Perhaps he is talking about spindle dysfunction, where the intrafusal portion of the spindle (which is innervated by a gamma motor neuron) is either excited or inhibited. The gamma’s are more of a slave to the interneuronal pool (in the cord), which would be the sum total of all excitatory and inhibitory input to that area (ie the central integrated state). This not only reflects local receptor input but also cortical information descending (from areas 4s and 6 in the precentral gyrus) AND descending information from the caudal reticular formation.

Based on what you sent, I do not agree with the 1st 2 sentences. I was not aware about increased receptor density of Sharpeys fibers. I did a quick search and found this: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2100202/  , which eludes to it and here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3098959/. I will have to dive in more when I have time.

Not sure why O/I attachments are tender in inhibited muscles. I find them tender in most folks. Maybe because inhibited muscles ave altered receptor function and that preloads the nociceptive afferent pathway or at least that neuronal pool? Are they closer to threshold for some reason? Not sure. LMK what you find.

Thanks for getting me jazzed about sharpeys fibers!

for those of you who need to know YES, there will be a forthcoming Sharpeys fibers article

Dr. Ryan: That’s what I thought.  Thanks for looking into it and I will check out those links.  You have jazzed me plenty of times over the years.  Glad I could jazz you up for a change.  Have a great weekend.

Yes, Dr Ivo is definitely an uber neuro geek, especially when he spends time on the weekend talking about spindles!

all material copyright 2013 The Homunculus Group/ The Gait Guys. All rights reserved. Please as before you lift our stuff.

Previously unreleased Video Available for download

“Performance Theories: Dialogues on Training Concepts”

How about some one on one with Shawn and Ivo? Hear our thoughts on:

• What is the definition of the core and what does it entail ?

• Physiologic overflow of muscles with respect to joint motion

• Isotonic Exercise concepts

• Physiologic characteristics of muscle types

• Strength Training: Neural Adaptation

• Motor Pattern Muscle Compensation Concepts

• Exercise Prescription Concepts

• Hip Extension Motor Pattern: A discussion on compensations

• Neurologic Reciprocal Inhibition: Principles of joint movement and stability

• The Concept of Tight and Short Muscles: They are different

• Stretching: Good or Bad?

We tackle the tough questions and provide real world answers.  An hour packed with hours worth of information! Download your copy here from Payloadz.

all material copyright 2009 The Homunculus Group/ The Gait Guys. All rights reserved.

acupuncture and muscle strength

“The present study shows that a single acupuncture treatment was efficacious for improving isometric quadriceps strength in recreational athletes. These results might have implications not only for athletic performance enhancement, but also for rehabilitation programs aimed at restoring neuromuscular function."  

Wow. What a statement! If you read the abstract, you will also read this ”The difference in the mean change in MIVF from baseline between acupuncture (46.6 N) and sham laser acupuncture (19.6 N) was statistically significant (p < 0.05), but no significant difference was found between acupuncture (46.6 N) and sham acupuncture (28.8 N)“  

So what was "sham acupuncture”? Simply put, acupuncture to non acupuncture meridian points. In other words, they put needles in muscles, just not on established meridians. Hmmm…Sounds alot like a form of dry needling. When you place a needle in a muscle, there is a good chance you will stimulate (or change function) of a muscle spindle or golgi tendon organ (length and tension receptors we have talked about before. see here, here, here, here, and here. guess we wrote about them a bit, eh?). Sham acupuncture still showed a positive result.                                                                  

                                                                                                                             

The bottom line? Needling the muscle changes how it contracts. It can be a useful tool for improving performance and rehabilitation.                                                                                                                                                                    

The Gait Guys. Geeks to the core. Bringing you the information to help you make better decisions with every post.  

European Journal of Applied Physiology

September 2010, Volume 110, Issue 2, pp 353-358

Immediate effects of acupuncture on strength performance: a randomized, controlled crossover trial

• Markus Hübscher,
• Lutz Vogt,
• Thomas Ziebart,
• Winfried Banzer

Download PDF (205 KB) View Article

Abstract

The present study investigated the immediate efficacy of acupuncture compared to sham acupuncture and placebo laser acupuncture on strength performance. A total of 33 recreational athletes (25.2 ± 2.8 years; 13 women) were randomized to receive acupuncture, sham acupuncture (needling at non-acupuncture points) and placebo laser acupuncture (deactivated laser device) in a double-blind crossover fashion with 1 week between trials. Assessment included bipedal drop jumps for maximum rebound height and quadriceps maximum isometric voluntary force (MIVF). Furthermore, surface electromyography (EMG) was used to measure the EMG activity of the rectus femoris muscle during a 30-s sustained MIVF of the knee extensors. Mean power frequency (MPF) analysis was applied to characterize muscular endurance. Measurements were performed at baseline and immediately after treatment by a blinded investigator. Repeated measures ANOVA and post hoc paired-sample t test with Bonferroni–Holm correction were used for statistical analysis. The difference in the mean change in MIVF from baseline between acupuncture (46.6 N) and sham laser acupuncture (19.6 N) was statistically significant (p < 0.05), but no significant difference was found between acupuncture (46.6 N) and sham acupuncture (28.8 N). ANOVA did not show statistically significant treatment effects for drop jump height or MPF. The present study shows that a single acupuncture treatment was efficacious for improving isometric quadriceps strength in recreational athletes. These results might have implications not only for athletic performance enhancement, but also for rehabilitation programs aimed at restoring neuromuscular function.

http://link.springer.com/article/10.1007%2Fs00421-010-1510-y

all material copyright 2013 The Gait Guys/ The Homunculus Group. All rights reserved.

Back and Better than ever….

More on the Core. Excerpted from some previously unreleased material which will be available for download soon…

High Heels and …..Orthotics?

What better way to end the year than to talk about something that some of you have worn last evening. Not only clean underwear, but also high heels!

You have heard all about high heels here on the blog (if not, click here). Now here is some info that may be surprising! This study found that increased heel height caused increased plantar pressures (no surprises) BUT the use of an orthotic or arch pad, attenuated impact forces. IOHO not a reason to wear heels (though we DO like the way they look : )) but if you need to wear them (really? you need to wear them?), then maybe consider an insert to make it more bearable.

Ivo and Shawn                                              

Appl Ergon. 2005 May;36(3):355-62.

Effects of shoe inserts and heel height on foot pressure, impact force, and perceived comfort during walking.

Yung-Hui L, Wei-Hsien H.

Source

Department of Industrial Management, National Taiwan University of Science and Technology, No. 43, Kee-Lung Road, Sec IV, Taipei, Taiwan, 106 ROC. yhlee@im.ntust.edu.tw

Abstract

Studying the impact of high-heeled shoes on kinetic changes and perceived discomfort provides a basis to advance the design and minimize the adverse effects on the human musculoskeletal system. Previous studies demonstrated the effects of inserts on kinetics and perceived comfort in flat or running shoes. No study attempted to investigate the effectiveness of inserts in high heel shoes. The purpose of this study was to determine whether increasing heel height and the use of shoe inserts change foot pressure distribution, impact force, and perceived comfort during walking. Ten healthy females volunteered for the study. The heel heights were 1.0cm (flat), 5.1cm (low), and 7.6cm (high). The heel height effects were examined across five shoe-insert conditions of shoe only; heel cup, arch support, metatarsal pad, and total contact insert (TCI). The results indicated that increasing heel height increases impact force (p<0.01), medial forefoot pressure (p<0.01), and perceived discomfort (p<0.01) during walking. A heel cup insert for high-heeled shoes effectively reduced the heel pressure and impact force (p<0.01), an arch support insert reduced the medial forefoot pressure, and both improved footwear comfort (p<0.01). In particular, a TCI reduced heel pressure by 25% and medial forefoot pressure by 24%, attenuate the impact force by 33.2%, and offered higher perceived comfort when compared to the non-insert condition.