This week Dr Ivo talks about interneurons and interneuronal pools. Sounds a little unexciting till you learn the importance of these little buggers!
Enjoy!
Why Runners need to take a page out of their automobile maintenance manual when it comes to running injury prevention.
Tissues have limits. They are like a tire, they only have so much tread on them before they show pathology. But like a tire, it takes time for a wear pattern to show up enough to make the tire wobble or the axle to pull the car mildly towards the ditch. Take a spinal disc, it has a certain number of compression and load cycles before it begins to desiccate, especially in the higher load / transition zones of the spine. Cartilage has a certain number of cycles before it begins to desiccate and crack/fissure and flake. Osteoarthritis then begins its slow sneaky onset. Tendons and ligaments have the same “limited lifespan” especially if loaded imperfectly with strained joint loads. Just because someone is pain free doesn’t mean they are safe. The abnormal load on an ITB band doesn’t begin the moment that pain presents itself. The problem brews in the background long before there is pain. Pain and injury represent a failure point in the mechanism. At this point it is too late. Being in medicine, we would be just like all the others if we crisis managed every athlete that walks in the door. So, we are in the game of prevention. We know our biomechanics, we know our orthopedics, physiology and neurology as good as the best out there. And so , we are well positioned on the front lines to identify problems before they ensue, and pick up on that aberrant wear pattern on the proverbial “tire” long before the pattern of wear is so bad that an injury is immanent and a foregone conclusion. So, this bodes the bigger question, just because you are injury free for many marathons and decades, doesn’t mean you shouldn’t take your car in , have its tires rotated, lug nuts snugged up, and alignment tweaked so that your car’s life will be maximized. Remember, unlike a car, we get one set of tires. We cannot replace bolts, we cannot remove the rust or put in a new oil or air filter. All we can do it make sure our “car” , our body, is working as best it can with the anatomical parts it has.
We do not think anyone would disagree that leaving alone and ignoring a 99% stenosed artery in the heart’s “widow maker” artery is a good idea just because someone hasn’t had a heart attack yet. Checking the body for malfunction early can prevent some unpleasant problems down the road. Pain or tightness is the dashboard’s “check engine” light. Regular check ups should keep that light off and reduce the sudden anxiety that comes when it turns on.
In summary, we take our cars in for tune up maintenance 2-3 times a year. And usually we drive away without the car driving too much different. But, we are at ease knowing it is in tip top shape and can go another 6000 miles before it might show signs of wear. We should do the same with our body and our gait mechanics and fix and change the little things that are sneaking up on us that could trigger that “check engine” light. By the time it comes on, it could be too late and require major repairs which just might keep your “car” off the road for awhile while repairs are made. No one likes to hear from the mechanic, “well Mr. Jones…….if we had checked up on this earlier before it was a big problem, we could have prevented this expensive set back on the sidelines.”
Our bottom line, even if your running is pain and injury free for years on end (which would make you a rare bird as runners go), it should make sense to you that improving biomechanical deficiencies isn’t likely a bad thing for the long term. Rather, it is probably the smartest of choices to keep you on your journey down the road, around the next bend, one efficient step after another.
“An ounce of prevention is worth a pound of cure”. -Ben Franklin
In this PART 2 installment of Applied Hip Gait Biomechanics, Dr. Allen delves deeper into a complex topic and attempts to bring it to a level that everyone can understand and implement. Here he talks about the hip mechanics in relation to pelvic stability and gait.
It is our goal to share as much of our collective 37 years of clinical experience as we can in a medium that is usable, friendly and understandable to all viewers.
Thanks for taking time out of your busy lives to care about watching our videos.
Shawn & Ivo, ……. The Gait Guys
The New Brooks Pure Project line. 4 models in the line.
To set your understanding level for the entire video…… at the start he says the first shoe has a 14-10 offset. That means 10mm of foam under the forefoot, and 14 under the heel, almost a 1:1 heel rise:forefoot rise meaning that the heel is only raised 4 mm compared to the forefoot. This leaves a ramp angle probably well below 5 degrees, depending on your foot length. As he discusses the other 3 shoes, he will mention different offsets…… like 15-11 for the Pure Grit. Notice the net change is still 4mm offset. So they all have the same 4 mm heel rise. The 14-10 Pure Connect as the least amount of EVA foam under the foot, so you supposedly will “feel” the ground more. With less foam, you need to be a better shock absorber with your body. The Pure Flow is 18-14 offset, meaning more EVA foam for more cushion and shock absorption. Remember…. transitioning to minimalistic shoe wear like this means that your heel will be suddenly ~10 lower than it is used to in shoes. Your “trainers” , your older style shoes, have raised the heel and allowed for a slight shortening of the calf and achilles complex, let alone monkey’d around with the normal biomechanics that should have been occurring. So, suddenly dropping 10mm may take some time. Play it safe, start with every other short run, wean into them.
We have been waiting for this shoe line. We hope it holds up to our standards, and prior Brooks Standards.
The Gait Guys
Kicking gait?
/And now… A question from a reader….
Dr Allen- There are a few questions troubling me. The first one concerns the loss of the ankle rocker phase of gait which can have implications further up the kinetic chain. It concerns the interplay of gastroc and soleus. Is it possible for gastrocnemius to work as a knee extensor when the foot is in the closed chain position - especially if the bodies centre of mass has advanced in front of the knee joint ? Thanks - RB
Hi RB_____,
yes it is possible…….it is a retrograde movement as you have described.
it is not commonly seen, but can be, and usually manifests itself, in one of 2 ways.
Typically the client is more ligamentously lax than others……..and they tend to have a “kicking” type gait, where they thrust the leg out in front, like kicking a ball, with each step forward. This causes a heavy heel strike and locks the knee in preparation for midstance, and then follows your thinking. By the way, this client also seems to like standing in a hyperextended knee position at rest.
We remember that the gastroc soleus group begins to fire in the first 10% of stance phase (it is acting as a knee extensor here); to promote eccentric deceleration of the forward moving tibia, and continues to fire until terminal swing. It is believed the soleus provides much of the deceleration force and the gastroc assists in inverting the ankle at midstance and primarily flexes the knee at pre swing, just prior to toe off (Nordin, Frankel 2001). If the gastroc /soleus group fires prematurely, or excessively, particularly in prior to midstance, then we see the action you describe, and it manifests itself as premature heel rise and loss of ankle rocker.
A sudden hyperextesion at midstance or later, in a neurologically competent individual, is unlikely, as he force is too abrupt at this point and there is too much of a mechanical disadvantage.
We hope this helps explain things a bit. Please email us back if it doesn’t!
Uber Geeks, Shawn and Ivo
Listening to music while you run. Research shows there is something to it.
/J Sci Med Sport. 2011 Jul 29. [Epub ahead of print]
Effects of synchronous music on treadmill running among elite triathletes.
Terry PC, Karageorghis CI, Saha AM, D'Auria S.
Source
Department of Psychology, University of Southern Queensland, Australia; Centre of Excellence for Applied Sport Science Research, Queensland Academy of Sport, Australia.
Abstract
Music can provide ergogenic, psychological and psychophysical benefits during physical activity, especially when movements are performed synchronously with music. The present study developed the train of research on synchronous music and extended it to elite athletes using a repeated-measures laboratory experiment. Elite triathletes (n=11) ran in time to self-selected motivational music, a neutral equivalent and a no-music control during submaximal and exhaustive treadmill running. Measured variables were time-to-exhaustion, mood responses, feeling states, RPE, blood lactate concentration, oxygen consumption and running economy. Time-to-exhaustion was 18.1% and 19.7% longer, respectively, when running in time to motivational and neutral music, compared to no music. Mood responses and feeling states were more positive with motivational music compared to either neutral music or no music. RPE was the lowest for neutral music and highest for the no-music control. Blood lactate concentrations were lowest for motivational music. Oxygen consumption was lower with music by 1.0-2.7%. Both music conditions were associated with better running economy than the no-music control. Although neutral music did not produce the same level of psychological benefits as motivational music, it proved equally beneficial in terms of time-to-exhaustion and oxygen consumption. In functional terms, the motivational qualities of music may be less important than the prominence of its beat and the degree to which participants are able to synchronise their movements to its tempo. Music provided ergogenic, psychological and physiological benefits in a laboratory study and its judicious use during triathlon training should be considered.
Well, in some ways, Barefoot IS better!
In those famous words: Res ipsa loquitur (The thing speaks for itself)…Well sort of…
Though some research is conflicting regarding barefoot running as being better, or more injury preventative, chalk one up for the efficiency of barefoot.
Glossary:
vVO is percentage of maximal velocity of graded exercise test. in this case 70%.
VO(2) is the maximal amount of O2 the body utilizes for an exercise
RPE: is how hard you perceive you are working for a given exercise or task
video provided courtesy of Two Rivers Treads and Newton Running
Int J Sports Med. 2011 Jun;32(6):401-6. Epub 2011 Apr 6. Oxygen cost of running barefoot vs. running Shod. Hanson NJ, Berg K, Deka P, Meendering JR, Ryan C. Source
Health, Physical Education and Recreation, University of Nebraska at Omaha, United States. njhanson@gmail.com
Abstract
The purpose of this study was to investigate the oxygen cost of running barefoot vs. running shod on the treadmill as well as overground. 10 healthy recreational runners, 5 male and 5 female, whose mean age was 23.8±3.39 volunteered to participate in the study. Subjects participated in 4 experimental conditions: 1) barefoot on treadmill, 2) shod on treadmill, 3) barefoot overground, and 4) shod overground. For each condition, subjects ran for 6 min at 70% vVO (2)max pace while VO (2), heart rate (HR), and rating of perceived exertion (RPE) were assessed. A 2 × 2 (shoe condition x surface) repeated measures ANOVA revealed that running with shoes showed significantly higher VO (2) values on both the treadmill and the overground track (p<0.05). HR and RPE were significantly higher in the shod condition as well (p<0.02 and p<0.01, respectively). For the overground and treadmill conditions, recorded VO (2) while running shod was 5.7% and 2.0% higher than running barefoot. It was concluded that at 70% of vVO (2)max pace, barefoot running is more economical than running shod, both overground and on a treadmill.
Pretty cool, eh?
Ivo and Shawn, 2 geeks making a difference
Forefoot stiffness. It’s all in the supination…
Remember a month ago when we talked about the basics of gait? If not, please see posts the week of 6/27 for a in depth discussion
Suffice it to say, in stance phase (about 60% of the walking and 40% of the running gait cycles) we have 2 motions occurring: pronation and supination. In pronation (which begins as soon as the foot hits the ground and should end at midstance) the foot is becoming a mobile adaptor, so it can adapt to irregular surfaces and act as a shock absorber.
In supination (which begins at midstance and ends at preswing) the foot is becoming a rigid lever, to assist in transferring muscular forces to the lower limb to propel us forward.
The picture above shows supination nicely. Remember that when one foot is in midstance, the opposite leg (in swing phase) assists in supination.
This study (IOHO) demonstrates the principle of supination nicely and demonstrates the (major) role the foot plays in forefoot stiffness.
J Biomech. 2005 Sep;38(9):1886-94. A comparison of forefoot stiffness in running and running shoe bending stiffness. Oleson M, Adler D, Goldsmith P. Source http://www.ncbi.nlm.nih.gov/pubmed/16023477
Department of Mechanical and Manufacturing Engineering, University of Calgary, 2500 University Drive, N.W. Calgary, Alberta, Canada T2N 1N4.
Abstract
This study characterizes the stiffness of the human forefoot during running. The forefoot stiffness, defined as the ratio of ground reaction moment to angular deflection of the metatarsophalangeal joint, is measured for subjects running barefoot. The joint deflection is obtained from video data, while the ground reaction moment is obtained from force plate and video data. The experiments show that during push-off, the forefoot stiffness rises sharply and then decreases steadily, showing that the forefoot behaves not as a simple spring, but rather as an active mechanism that exhibits a highly time-dependent stiffness. The forefoot stiffness is compared with the bending stiffness of running shoes. For each of four shoes tested, the shoe stiffness is relatively constant and generally much lower than the mean human forefoot stiffness. Since forefoot stiffness and shoe bending stiffness act in parallel (i.e., are additive), the total forefoot stiffness of the shod foot is dominated by that of the human foot.
The Geeks of Gait: Ivo and Shawn
Born to Run?
Perhaps we really were born to run. This study looks at the forefoot, the phalanges and their potential role in the evolution of our feet.
We know impact forces increase with running, so it makes sense that physical and metabolic demand to continue forward momentum would increase as well. Longer lever arms (such as longer toes) would require greater torque on the muscles as well as increased lift of the foot (to provide ground clearance), and most likely a different orientation of the rearfoot and trochlea that the flexor tendons would have to pass through. This would probably result in a more cavus, rigid foot as well.
The study did not state, but suggested muscular recruitment of the flexors is distinctly different in walking vs running, and that there is less “balance” between the flexors and extensors. We contend that with appropriate gait patterns (ie, using the glutes as a primary hip extensor), long flexor activity would be more balanced with long extensor activity and this disparity would not be seen.
The video has nothing to do with the study, we just thought it was pretty funny
Sorting out the details so you don’t have to; The Gait Guys
J Exp Biol. 2009 Mar;212(Pt 5):713-21. Walking, running and the evolution of short toes in humans. Rolian C, Lieberman DE, Hamill J, Scott JW, Werbel W. Source http://www.ncbi.nlm.nih.gov/pubmed/19218523
Department of Anthropology, Harvard University, Cambridge, MA 02138, USA. cprolian@ucalgary.ca
Abstract
The phalangeal portion of the forefoot is extremely short relative to body mass in humans. This derived pedal proportion is thought to have evolved in the context of committed bipedalism, but the benefits of shorter toes for walking and/or running have not been tested previously. Here, we propose a biomechanical model of toe function in bipedal locomotion that suggests that shorter pedal phalanges improve locomotor performance by decreasing digital flexor force production and mechanical work, which might ultimately reduce the metabolic cost of flexor force production during bipedal locomotion. We tested this model using kinematic, force and plantar pressure data collected from a human sample representing normal variation in toe length (N=25). The effect of toe length on peak digital flexor forces, impulses and work outputs was evaluated during barefoot walking and running using partial correlations and multiple regression analysis, controlling for the effects of body mass, whole-foot and phalangeal contact times and toe-out angle. Our results suggest that there is no significant increase in digital flexor output associated with longer toes in walking. In running, however, multiple regression analyses based on the sample suggest that increasing average relative toe length by as little as 20% doubles peak digital flexor impulses and mechanical work, probably also increasing the metabolic cost of generating these forces. The increased mechanical cost associated with long toes in running suggests that modern human forefoot proportions might have been selected for in the context of the evolution of endurance running.
We always think of ourselves as the CSI or NCIS geeks of gait. We were aware of forensic analysis of footprints and this article is just the icing on the cake!
article source: http://www.google.com/hostednews/afp/article/ALeqM5jhIh9jpQmYAgl6Rv0uBjNQgT1ItQ?docId=CNG.4ecd62b490d0f49529b2cfb2c331d332.481
Security first: When a footstep is like a fingerprint
PARIS — How a bare foot strikes the ground as one walks reveals your identity almost as well as a fingerprint, according to a study released Wednesday.
The discovery means that one day retinal scans, voice recognition and old-fashioned mugshots may be joined by foot-pressure patterns as a means of confirming ID, it suggests.
Previous research has shown that everyone has a unique stride. Computers can determine “gait patterns” – the way a person walks, saunters, swaggers or sashays – with up to 90-percent accuracy.
Scientists led by Todd Pataky at Shinshu University in Tokida, Japan, looked at enhancing this finding by measuring how the foot hits and leaves the ground during walking.
They used 3-D image processing and a technique called image extraction to analyse the heel strike, roll-to-forefoot and push-off by the toes among 104 volunteers.
Footstep patterns were matched to the individual with 99.6 percent accuracy, according to their paper, published on Wednesday in Britain’s Journal of the Royal Society Interface.
The study is “proof of concept,” meaning that it was carried out in experimental conditions among volunteers who were barefoot to see whether the theory was sound.
In an email exchange with AFP, said the technology would be useful in security checks.
But it would only work in situations where an individual wants to be recognised, “since anyone can modify their gait,” he explained.
“Automated airport security checks, ATM security, controlled building access – in all these cases, an individual could walk normally to be positively identified.”
Further work is needed to see whether feet that are shod throw up similar telltale patterns.
“We have some pilot data for walking with shoes, but have not yet conducted systematic testing,” Pataky said.
Too cool, eh?
Ivo and Shawn
Evolved to run: How we keep our noodle steady while we run.→
/Have you ever given thought to your head movements during running or walking ? Ever wonder why the world doesn’t seem to bound around as we move ? Wonder why things look different through your eyes when you yourself are running as compared to when you are watching the nauseating jerky video of someone wearing a camera on their head ?
Bryce Vickmark for The New York Times interviewed Dr. Lieberman of the Harvard Nature study…. here is a quote from that interview.
“We (Lieberman) realized that there were special features in the human neck that enable us to keep our heads still. That gives us an evolutionary advantage because it helps us avoid falls and injuries. And this seemed like evidence of natural selection in our ability to run, an important factor in how we became hunters rather than just foragers and got access to richer foods, which fueled the evolution of our big brains.”
__________________________________________________
Gait Guys say this….. “The ability to see clearly while moving / running / hunting is a well rooted primitive neurologic function in man. The visual-motor system (oculomotor system) is capable of assimilating the visual information and making calculations for the small head displacements that occur with movement via neural mechanisms that control three-dimensional head posture while coordinating three-dimensional eye orientation. The body’s movements as a whole (eye, head and body) are part of a coordinated series of sensory-motor events that are used to voluntarily reorient the axis of gaze between objects. Body movements themselves can make a predictable contribution to gaze shifts and one study (link) has shown that single neurons (yes, one small neuron all by itself) can code motor commands to move the body as well as the head and eyes. It is a finely tuned system, an amazing system. One we rarely appreciate anymore since running during a hunt for food no longer occurs in urban America. Of course this function is seamlessly tested everyday in athletes, unless of course you are a football or other impact sport athlete, and have accelerated your noggin one too many times. Ask any aging boxer or ex-football player how their visual-motor system is doing ! (and since it is NFL and high school football season….. here is support for those dropped endzone passes in the concussed wide receivers...LINK and. LINK)
NY Times link: for the Lieberman article.
We are The Gait Guys…….. running and hunting outside the box everyday, looking for answers.
So, does the angle your foot strikes the ground really matter? With all the talk about minimalistic training and striking under the body being less stress on the human frame and more efficient, you would think so. Here is one study that seems to support that premise.
from the studies conclusion: “Our results indicate that individuals with a larger knee angle (i.e., greater extension) 50 ms prior to initial contact (IC) experience a higher ROL (Rate of loading) during gait and have poorer proprioceptive scores.”
Proprioception, gait kinematics, and rate of loading during walking: are they related? Riskowski JL, Mikesky AE, Bahamonde RE, Alvey TV 3rd, Burr DB.
J Musculoskelet Neuronal Interact. 2005 Oct-Dec;5(4):379-87.
http://www.ncbi.nlm.nih.gov/pubmed/16340143
Helping to promote gait literacy…We are…The Gait guys
Something a little lighter…..
Borrowed from one of our good friend and fellow physicians site, Dr Mark Cucuzella’s Freedom Run http://freedomsrun.org/ . This clip is truly inspirational.
Ivo and Shawn
Here are some excerpts from a talk we did earlier in 2011. Dr. Shawn Allen talks to a private industry group about shoes, shod and unshod ambulation, the research based facts from both old and new studies, and thoughts about the benefits and caveats of going into minimalistic footwear or barefoot.
Thank you for watching our video, please feel free to share it with anyone and everyone. We have lots of other videos here on youtube.
Shawn and Ivo…..The Gait Guys
