Training Tip: Ditch the Flip Flops. Our mention in Triathlete magazine.→
/Our brief mention in Sept 16th issue of Triathlete magazine
link is above….. Jene Shaw the editor did a nice job on a touchy subject.
Training Tip: Ditch The Flip-Flops
Published: Sep 16th 2011 3:09 PM UTC by Jené Shaw
Although they date back to King Tut and Cleopatra, your favorite thong-style sandal may be bad for your running health according to biomechanical experts The Gait Guys (Thegaitguys.com), Dr. Shawn Allen and Dr. Ivo Waerlop.
In 2008 Auburn University researchers found that wearing flip-flops alters your gait, which can result in biomechanical issues from your foot to your spine. “In flip-flops the kinetic chain is essentially asked to function differently,” Allen says. “They can force changes in step and stride length, reduce function of the glutes, and compromise lower leg and foot intrinsic muscles, to name a few.”
When wearing flip-flops, use of the foot intrinsic and toe extensor muscles is reduced in the stance phase of gait. What’s important about this is that the toe extensors, found in the lower leg, are synergists for ankle dorsiflexion (the upward movement of the foot), which is key in running. Without ample function of these muscles, the toe flexors, calf and Achilles shorten and tighten, which impairs optimal ankle and foot joint function.
3 strikes against flip-flops:
• Without sufficient strength in the anterior tibial compartment (the front of your lower leg) you are at risk for several problems, including shin splints.
• Lack of adequate function of the toe extensors can lead to toe flexor dominance (look to see if your toes have a gentle curl to them at rest; if so, you are in that group!) which has implications with general weakness of the foot muscles responsible for arch strength and general foot health.
• In order to keep a flip-flop on our foot, we tend to grip with our flexors, which forces us deeper into this scenario.
If you are going to wear sandals and you want healthier feet, The Gait Guys recommend wearing sandals that have straps that fasten to your heel or lower leg.
This is a nice study looking at lateral gastroc activity and changing firing patterns with speed of movement. It also melds nicely with yesterdays Neuromechanics post…
Those darn Ia afferents….
You remember them, large diameter afferent (sensory) fibers coming from muscle spindles and appraising the nervous system of vital information like length and rate of change of length of muscle fibers, so we can be coordinated. They act like volume controls for muscle sensitivity. Turn them up and the muscle becomes more sensitive to ANY input, especially stretch (so they become touchy…maybe like you get if you are hungry and tired and someone asks you to do something); turn them down and they become less or unresponsive.
Their excitability is governed by the sum total (excitatory and inhibitory) of all neurons (like interneuron’s) acting on them (their cell bodies reside in the anterior horn of the spinal cord).
If we slow things down, the rate of change of length slows as well and excitability decreases, like we see in this study (3-6% slower). We also notice that the length of contraction increases; hmmm, why doesn’t it decrease?
Remember these folks are on a treadmill. The treadmill is constantly moving, opposite the direction of travel. With the foot on the ground, this provides a constant rate of change of length of the gastroc/soleus (ie, it is putting it through a slow stretch); so , once the muscle is activated, it contracts for a longer period of time because of the treadmill putting a slow stretch on the gastroc (and soleus).
This article also talks about people with upper motor neuron lesions. An important set of inhibitory neurons come from higher centers of the brain, in the motor cortex. These tend to attenuate the signals affecting the Ia afferents, and keep us stable. When we have an upper motor neuron lesion (like a brain lesion or stroke), we lose this “attenuation” and the stretch reflexes (and muscle tone) becomes much more active (actually hyperactive), making the muscle more sensitive to stretch. This loss of attenuation, along with differing firing patterns of the gastroc are important to remember in gait rehab.
The soleus and medial gastroc begin firing in the first 10% of the gait cycle (at the beginning of loading response) and fire continuously until pre swing (peaking just after midstance). The lateral head begins firing at midstance; both leads (along with soleus) decelerate the forward momentum of the tibia, flex the knee at midstance, and the medial head assists in adducting the calcaneus to assist in supination.
We remain, inexplicably….The Gait Guys
Effects of treadmill walking speed on lateral gastrocnemius muscle firing.
by Edward A Clancy, Kevin D Cairns, Patrick O Riley, Melvin Meister, D Casey Kerrigan
American journal of physical medicine rehabilitation Association of Academic Physiatrists (2004) Volume: 83, Issue: 7, Pages: 507-51 PubMed: 15213474
Abstract
OBJECTIVE: To study the electromyographic profile-including ON, OFF, and peak timing locations-of the lateral gastrocnemius muscle over a wide range of walking speeds (0.5-2.1 m/sec) in healthy young adults. DESIGN: We studied gastrocnemius muscle-firing patterns using an electromyographic surface electrode in 15 healthy subjects ambulating on a treadmill at their normal walking speed and at three paced walking speeds (0.5, 1.8, and 2.1 m/sec). Initial heel contact was determined from a force-sensitive switch secured to the skin over the calcaneous. RESULTS: For all speeds, the gastrocnemius firing pattern was characterized by a main peak, occurring 40-45% into the gait cycle, that increased in amplitude with walking speed. Speeds of > or =1.3 m/sec produced a common electromyographic timing profile, when the profile is expressed relative to the stride duration. However, at 0.5 m/sec (a speed typical of individuals with upper-motor neuron lesions), the onset of gastrocnemius firing was significantly delayed by 3-6% of the gait cycle and was prolonged by 8-11% of the gait cycle. CONCLUSION: Many patients with upper motor neuron lesions (e.g., stroke and traumatic brain injury) walk at speeds much slower than those commonly described in the literature for normal gait. At the slow walking speed of 0.5 m/sec, we have measured noticeable changes in the electromyographic timing profile of the gastrocnemius muscle. Given the importance of appropriate plantar flexor firing patterns to maximize walking efficiency, understanding the speed-related changes in gastrocnemius firing patterns may be essential to gait restoration.
More Lactate:
Before we talk about determining blood lactate levels, we need a deeper understanding of the energy producing systems at play, as well as some commonly used terminology.
There are 2 main systems for producing energy in the body, the aerobic system and anaerobic system. There is a 3rd system, the Creatine Phosphate system, which provides energy for very short bursts of a few seconds, or until your creatine phosphate stores are depleted. we will concentrate on the 2 main ones.
The aerobic system or aerobic metabolism, utilizes oxygen, using predominately fats & some carbohydrates for energy along with recycled lactate which is produced at low levels and metabolized efficiently. This is your endurance energy system. You may still have recurring nightmares about this from freshman biology, also known as the Krebs (or Citric Acid) Cycle
Your lactate threshold (LT) is a highly aerobic point where lactate levels in the blood are still low but just starting to reach steady state levels. Your LT is the most efficient effort level that you can sustain for long periods of time without going in to your energy reserves (i.e. glycogen). Beyond this point, you are exceeding your ability to recycle lactic acid back into the Citric Acid Cycle and lactate levels begin to rise; changing local blood pH and affecting local chemical reactions.
The anaerobic system does not utilize oxygen, using predominantly carbohydrates for energy. An efficient anaerobic system will produce a lot of lactic acid as its by-product. As you know, in large amounts, this causes the burn and fatigue you often feel when working hard. Thus, your anaerobic threshold (AT) is much more stressful and is therefore only sustainable for shorter periods of time.
What does this mean?
For the endurance athlete, the BALANCE of these two systems must be developed optimally for their chosen event. Performing a lactate test (to be discussed in another post) will help determine the relative contribution of each system. In general, the well-developed endurance athlete will produce very little lactate even at high speeds. Endurance sport athletes, such as cyclists, Ironman athletes, triathletes and top marathon runners need to be highly aerobic, which means that very little lactate is produced even at peak speeds and testing reveals a very flat lactate curve. Most of their energy comes from aerobic sources.
Optimizing lactate threshold development is the main goal of endurance training, and racing at or near LT proves the most efficient route to a solid race day performance.
So, how can you use this information for training? Watch for an upcoming post on Lactate testing.
Yup, we know a thing or two about gait AND training.
The Gait Guys: Ivo and Shawn
The Ankle-Foot Orthosis : Another option for foot drop.
Do you have a client who suffers from some foot drop ? Do they have a classical AFO but it drives them nuts ? Foot drop occurs when the anterior compartment of the lower leg (mostly tibialis anterior and/or long toe extensors) gets compromised neurologically leaving a persons gait compromised during the swing phase and early half of stance phase. Early to mid stance phase of gait requires that the anterior compartment muscles slowly (eccentrically) lowers the foot to the ground in a controlled manner. When this is compromised the foot quickly, and without strategy, slaps to the ground thus rushing the persons gait onto the forefoot. This often occurs in an uncontrolled fashion and renders some balance and weight transfer complications. Then, during late stance phase, when the foot comes off of the ground merely by forward body progression, these clients leave the foot in the pointed plantarflexed position leaving the toes without proper clearance. This often leads to tripping and stumbling.
Always looking out for newer and better solutions, we came across this variation on the AFO (ankle-foot orthosis) strategy. It seems like it could have some advantages from a logistical side. Whereas the typical AFO comes under the foot and maintains the foot in a 90 degree ankle rocker (dorsiflexion) position this one has a bit of a dynamic effect. The bungee cord-like device should slowly lower the foot to the ground as well as help to spring the foot back into dorsiflexion for swing phase clearance so that the toes are not catching on the ground. Seems so simple we have to wonder. We might give this one a try on a few patients who have varying degrees of footdrop and report back.
Regardless, we wanted to share……. we love outside the box thinking. Especially when it is so simple !
bravo !
shawn and ivo…………. toss in a side of orthopedics and a main course of neurology, sprinkle a little biomechanics on that and you have a well rounded meal. We are …… The Gait Guys
The Gait Guys indirect link to Sidney Crosby of the NHL and his head trauma.
So, how did the Gait Guys get so smart ? Both Dr. Allen and Dr. Ivo studied in the field of chiropractic neurology. Dr. Ivo had the wonderful opportunity to study directly under Dr. Carrick for several years. Dr.Carrick is the leader in the field of functional neurology. Dr Ivo studied under the best out there. Dr. Ivo is a diplomate of the chiropractic neurology board, one of the most challenging diplomates to attain.
Most recently Dr. Carrick was asked to evaluate and treat Sidney Crosby arguably the best player in the NHL. EVeryone was failing on helping Sidney, until Dr. Carrick was begged to come into the picture to help.
Here is an awesome press conference with Dr. Carrick’s talk starting at 7:40 into the press conference. Enjoy
The Gait Guys, ……. Ivo and Shawn……. not your average doctors.
Reebok International Ltd has agreed to pay $25 million to settle charges that it made unsupported claims
/what we were saying all along about these types of shoes and MBT’s…….
____________________________
By Diane Bartz in Washington and Nivedita Bhattacharjee in Bangalore | Reuters
WASHINGTON (Reuters) - Reebok International Ltd has agreed to pay $25 million to settle charges that it made unsupported claims that its “toning shoes” provide extra muscle strength, the U.S. Federal Trade Commission said on Wednesday.
The money will go toward consumer refunds.
Reebok advertisements said the shoes strengthened hamstrings and calves by up to 11 percent more than regular sneakers, and toned the buttocks by up to 28 percent more, the FTC said.
read the rest here…… link below
http://shine.yahoo.com/channel/health/reebok-paying-to-settle-charges-over-shoe-claims-2571097/
Gait Forensics: Gait Recognition Software.→
/Imagine you are a wanted criminal or terrorist. You know that in the soon-to-be police state that America is leaning towards, there will be cameras on every corner, in every building, on every public transportation service. Heck, it is in many of these places already. So, what is a criminal to do ? Hiding their identity was once the way but it is coming to an end because of the improving facial recognition computer programs currently being used. A once simple process of growing some facial hair, wearing sunglasses, changing haircut or color, wear hats is coming to an end. Still, there are so many other ways criminals can hide amongst us and from the pending camera-happy America that we are soon becoming. So, what is America’s next step to stay ahead of all this ?
Yup, why not begin a database of gait traits that can be identified; sort of like an AFIS for feet? After all, people do have different foot types, and combining that with gait patterns provides unique clues to an what makes us unique.
In the above article , “A team of New York University researchers has honed in on motion capture as a particularly promising approach to analysis. Associate computer science professor Chris Bregler is studying whether potential security threats can be identified via unique patterns of movement. How might someone walk if he was carrying a bomb in his backpack?” “A person’s body moves differently when it must compensate for some unnatural burden, such as a heavy backpack or even high-heeled shoes, says Bregler.”
“Bregler and his team have identified certain movement signatures with the help of the same motion-capture technology used for special effects in the Lord of the Rings and Harry Potter movies.”
In present day America, one unfamiliar with suicide bombers, we feel safe most of the time. But as these guys are investigating, carrying excess weight that one is not typically accustomed to, could generate some traceable gait characteristics that a camera could pick up on. But the problem, as we see it, is that if the terrorists know what we are looking for, they can train themselves to adapt to the added weight.
It took a decade or more for facial recognition software to become perfected by the government. It is so simple now that Facebook has thrust it upon all of our photo galleries. So who knows, in another decade or so, all of our gait patterns could be mapped and logged for the government and the “next Facebook” phenomenon.
Hopefully these companies will come calling on the guys of gait……. the experts.
Shawn and Ivo…….The Gait Guys
in the infamous words of Steven Tyler, …..“walk this way”……. or
the immortal words of James Taylor…..“there’s something in the way she moves …..”
want more from the article ? here is the link below
Are Barefoot Shoes really better ? NewYorkTimes article.→
/Read the full article, it is quite short…… but here is the gist of it…..
“The American Council on Exercise, a nonprofit group that reports on fitness, recently sponsored a small study to learn more about the popular footwear. Researchers from the University of Wisconsin, La Crosse, asked 16 women, all healthy recreational joggers ages 19 to 25, to spend two weeks getting used to running in the Vibram FiveFingers, a snug, glovelike shoe that weighs less than five ounces. The women were advised to use the shoes, the best-selling brand of barefoot sports shoes, three times a week for up to 20 minutes a day.”
“The researchers found that half of the women who switched to barefoot running or minimalist sports shoes failed to adjust their form, resulting in more wear and tear on their bodies, not less.”
Really? 2 weeks to “get used to them”? As we have said, countless times; you must earn your right to go minimalistic or barefoot. Foot competence is not created in a day, or in 2 weeks for that matter….
Shawn and Ivo. Two guys promoting gait competence
Green bodies: Lactic acid as a fuel source?
Your body can be greener? We don’t mean being a leprechaun. We mean being a better recycler. Read on…
For years, we’ve been told that lactic acid is a waste product that burns and shuts down muscles. It’s something athletes and fitness exercisers are urged to avoid. You’re told to work out just below your lactate threshold, where lactic acid begins to accumulate.
Well, some of that is correct, but it seems, most of it is wrong.
The aerobic and anaerobic energy systems have long been thought to operate as separate and distinct systems. Lactic acid was considered the enemy of aerobic metabolism, with the power in sufficient accumulations to bring it to a halt. But we are smarter than that now…
UC Berkley integrative biology professor George A. Brooks, has been studying lactic acid since doing his doctoral dissertation on the subject in the ‘70s. Brooks says the idea that lactic acid is bad and to be avoided “was one of the classic mistakes in the history of science.”
“The understanding now is that muscle cells convert glucose to lactic acid,” Brooks explains. “The lactic acid is taken up and used as a fuel by mitochondria, the energy factories in muscle cells. Mitochondria even have a special transporter protein to move the substance into them.”
So, your ability to recycle lactic acid into the Krebs (or Citric Acid Cycle) reflects a great deal about your aerobic performance and capacity. Aerobic metabolism and anaerobic metabolism, in fact, operate side by side in the mitochondria. The heart, slow-twitch muscle fibers, and breathing muscles actually prefer lactate as a fuel during exercise. In short, lactic acid is a significant energy source, actually a good thing.
Hinting, or perhaps suggesting, how athletes can and are using this revelation, Professor Brooks said in a recent press release: “The world’s best athletes stay competitive by interval training. The intense exercise generates big lactate loads, and the body adapts by building up mitochondria to clear lactic acid quickly. If you use it up [as an energy source], it doesn’t accumulate.”
Too much lactic acid is still bad, however. It causes distress and fatigue during exercise, altering the local pH of the tissues and changing chemical reactions. In extreme circumstances it can damage muscle cells.
So how can you learn to use lactic acid to your advantage? Stay tuned for the next lactate installment, coming to a Gait Guys Tumblr Blog near you….
Ivo and Shawn
Now here is something a little different. Check out this PhD Thesis submission. What you do DOES make a difference! as we have been saying: it is a cortical phenomenon.
http://www.graduate.technion.ac.il/heb/StudentsLec/amir%20haim/abstract.htm
Plasticity of Locomotor Patterns & Gait Conditioning via Controlled
Biomechanical intervention
Amir Haim, MD (Ph.D candidate)
Supervisor: Dr. Alon Wolf
Biorobotics and Biomechanics Lab, Faculty of Mechanical Engineering
Overall, the task of walking is attained by a proper kinematic trajectory command conveyed by the nervous system to its skeleto-muscular instruments which generate the appropriate kinetics. Extensive evidence indicates that motor program adaptations can compensate for losses in mechanical integrity through altered movement and muscle activation patterns. Further more, non surgical biomechanical manipulations, have been shown influence kinetic and kinematic parameters and to generate “active”-neuromuscular re-education.
In the present study we hypothesized that specific biomechanical challenges will stimulate matching biomechanical responses trough out the musculoskeletal kinematic chain. We further hypothesized that repetitive exposure to a biomechanical stimulus would generate a process of motor learning thus conveying plasticity of existing locomotor patterns and gait strategies.
To test our hypothesis; we examined two cohorts - healthy young male adults and subjects suffering from knee Osteoarthritis (OA). All participants underwent gait analysis comprising kinematic kinetic and ellcetromygragic patterns during gait. We modeled the direct locomotor response to controlled footwear-generated biomechanical manipulations utilizing a novel biomechanical apparatus comprising four modular elements . Further more we prospectively examined (via gait analysis and valid questioners) patients with abnormal gait patterns (due to knee osteoarthritis) who were subjected to extended biomechanical intervention.
Study results confirmed our hypothesis; A direct association was found between specific biomechnical challenges and direct kinetic and kinematic response in both healthy and OA subjects. Like wise, OA participants who where exposed to long term biomechanical interventions exhibited normalization of cartelistic gait patterns and had a favorable subjective outcome.
http://www.oandp.org/jpo/library/1993_02_039.asp
http://emedicine.medscape.com/article/320160-overview
Shoes are like oven mits for your feet. Railing walk. A different kind of gait today.
You will not be able to do this in traditional shoes that is for sure. The feet are amazing adaptable receptor organs, feedback is critical. Shoes dampen feedback.
Imagine if you had oven mits on all day long …… the hands would be handicapped.
have a great weekend fellow gait geeks.
shawn and ivo
