Posts Tagged ‘Vibrams’

Maximizing your Minimalist Footwear

Thursday, September 6th, 2012

This article originally appeared on Ptonthenet.com

Do you own a pair of minimalist shoes? If you do, you’re in good company.

    I present and teach all over the world, and I’ve seen minimalist shoe use among my fellow health and fitness professionals increase substantially, especially during the last 3 years. Enter any training facility or health club around the world and you are sure to see personal trainers wearing Vibrams or something similar. In fact, many fitness professionals have done away with other forms of footwear altogether and have embraced minimalist shoes as their full-time footwear.

    Minimalist shoes – also sometimes referred to as barefoot shoes – include shoes ranging from traditional-looking shoes with very thin soles and structural support around the rearfoot to tighter fitting “gloves” (like Vibrams) for the feet that allow for separation of each toe. The term “barefoot shoes” is, of course, an oxymoron…a shoe of any kind insulates the skin of the bottom of the foot from coming in direct contact with the support surface, in contrast to going truly barefoot. Still, while much of the relevant research has examined barefoot versus shod running, many have extrapolated the barefoot results to minimalist shoes and used the positive outcomes as a basis to make a shift in their preferred training and day-to-day footwear.

    Rather than focusing on the pros and cons of minimalist shoes, this article will instead examine how to maximize the benefits and minimize the risks of going minimalist. Let’s begin by taking a look at the science behind the movement

    The Science Behind Barefoot/Minimalist Running & Walking

    Many would argue that physical therapist Michael Warburton’s 2001 review of barefoot running in Sports Science was a major catalyst for the minimalist movement’s growth over the last decade. In 2009, journalist Christopher McDougall helped bring the concept of barefoot running to the masses with his bestselling book Born to Run: A Hidden Tribe, Superathletes, and the Greatest Race the World Has Never Seen.

    A number of studies have compared the science behind barefoot and shod running (Eskofiera et al., 2011; Altman & Davis, 2011; Hamilla et al., 2011), and of particular interest are the kinetic and kinematic data related to running economy and injury. Daniel Lieberman, professor of human evolutionary biology at Harvard University, has done several studies comparing barefoot and shod running and is often quoted by proponents of barefoot running. One recent study – “Foot Strike and Injury Rates in Endurance Runners: a retrospective study,” published online ahead of print by Medicine and Science in Sports and Exercise (2012) – found that rear foot strikers (typically runners in shoes) had twice as many lower extremity repetitive stress injuries as forefoot strikers (common in minimalist and barefoot runners). The competitive, college-aged cross country runners in the study all wore running shoes. (It should also be noted that this study was partially funded by Vibram USA.)

    But does this research on barefoot/minimalist running apply to people who do not necessarily run, yet spend the majority of their time in minimalist shoes?

    In terms of walking, lunging, and squatting, etc. the answer is no.

    To understand why, we need to first remember that the foot has two basic functional roles for human locomotion:

    1) to provide a rigid platform to propel the body forward, and
    2) to adapt to the surface it is on as bodyweight is accepted and through mid-stance.

    If the surface is consistently hard and flat, the foot will adapt to that surface by consistently flattening out. When running barefoot or minimalist, the forefoot strike creates an immediate need for active myofascial stabilization of the foot and ankle that prevents foot flattening. This does not occur with a heelstrike when barefoot or shod.

    But is flattening or pronating the foot a risk factor for injury? Not necessarily. In and of itself, pronation of the foot is supposed to occur. From a functional perspective, what it is important is: 1) how soon after the heel strike pronation occurs, 2) how fast maximal pronation occurs, and 3) how much total pronation occurs. Excessive pronation, however, can be a problem. Overpronation has been shown to correlate with increased tibial stress fractures (Hetsroni et al., 2008) and to affect pelvic alignment (Khamis & Yizhar, 2007). Further, asymmetrical amounts of pronation have been associated with a functional leg length discrepancy (Rothbart, 2006).

    Studies show reduced stance times and shortened stride lengths when walking barefoot versus shod. The first peak of ground reaction forces, however, occurs at the same time and with the same shape for both barefoot and shod walking (Sacco, 2010). This means that when walking barefoot (versus running) one does not assume a mid- or forefoot strike. The muscular activity and fascial loading that is so advantageous even on flat, hard surfaces during barefoot/minimalist running is simply not present with barefoot/minimalist walking. As a result, total time and exposure to flat, hard surfaces should be a consideration when you or your clients are wearing a minimalist shoe. A training session on flat, hard surfaces may be beneficial if there is variety in movements and loads the body experiences during that session. Nevertheless, the benefits of wearing minimalist shoes as “everyday” shoes may be debatable for many clients/athletes.

    Limitations of Minimalist Shoes

    The ligaments and joint capsules of the 33 joints in the foot are rich in proprioceptors, as is the ankle retinaculum. The retinaculum of the ankle has shown to be thickening of the fascia of the foot and leg and are dynamic, non-static structures that are also very rich in proprioceptors (Stecco, 2010). Therefore the plantar fascia of the foot and the ankle are intimately connected. Movement of these joints of the foot and ankle provide valuable information to the central nervous system (CNS) regarding maintenance of our upright posture, weight distribution and locomotion.

    When minimalist shoes are worn in highly predictable environments like health club floors, sidewalks, airports, and shopping malls, there is very little variation in the proprioceptive stimulation to the foot. In contrast, environments that have changing surfaces and surfaces of varying density that cause the joints of the foot to move with more variety will likely provide greater proprioceptive input to be processed by CNS. The variety in joint position creates much more diversity of muscular recruitment and fascial loading throughout the myofascial system. The evolutionary development of the human foot without shoes cannot be argued. We have to keep in mind that this development occurred over rocks, roots, branches on grounds with varying inclines in all directions.

    A second aspect to acknowledge with the minimalist shoe is the absence of any significant cutaneous stimulation if the shoes are exclusively worn on man-made surfaces. The bottoms of the feet are one of the areas of the body with the highest concentration of cutaneous receptors. These receptors are optimally stimulated when pressures and contact surfaces to the sole of the foot are variable. The fitness floor does not provide this kind of stimulation. For the cutaneuous receptors to be appropriately stimulated in a minimalist shoe, localized and varying pressures would be applied to the foot as with walking on a dirt trail.

    The plantar fascia and palmar fascia are tightly connected to the overlying skin. This skin/fascial relationship prevents the degree of sliding between skin and superficial fascia commonly seen in other areas of the body (Benjamin, 2009). This may be another connection in the role touch and pressure play in these two key areas as part of our evolutionary development.

    Philip Beach points out in Muscles and Meridians: The Manipulation of Shape (2010) that the soles of the feet are innervated by sensory nerve roots from L4/L5 and S1, and that these spinal segments are the most vulnerable in upright posture. This means we must provide the ample stimulation to the soles of the feet to keep the lower back safe. Beach goes on to call shoes “sensory deprivation chambers that cut down the raw information we need to stand and walk in our precarious upright manner.”

    There are other direct links from the sole of the foot to the health of our lower back. The small intrinsic and extrinsic muscles of the foot are innervated from L4 to S3. These same nerves also innervate muscles of the lumbar spine and pelvic floor.

    Bringing Minimalist & Barefoot Training to the Fitness Floor

    When wearing minimalist shoes themselves or recommending them to clients, trainers should be clear on their benefits and limitations. A body that has always worn supported shoes may not be able to tolerate changes to repetitive loading to the tissues of the foot and/ or lower leg for long periods of time on man-made surfaces. In a traditional training environment, it may be best to introduce the foot to minimalist shoes by reserving them for exercises that always have at least one foot in contact with the floor and involve multi-directional movements that create variability in joint positions throughout the foot and ankle.

    It stands to reason that if a minimalist shoe is worn consistently on flat, man-made surfaces, you can use your professional creativity to maximize the potential benefits of stimulating the foot during training sessions through motion and tactile stimulation. This can be done while wearing minimalist shoes, but tactile stimulation is further enhanced when using no foot covering at all.

    At the Function First studio, we built a simple but elegant rock garden containing three sections: one with small rocks, one with medium rocks, one with large rocks. Either prior to or at the conclusion of a training session, depending on individual needs, our clients will spend time in their bare feet on the rocks. Some clients walk on the rocks prior to a session to obtain the benefits of mobilizing the plantar fascia and muscles of the foot. Others walk on the rocks at the end of a corrective exercise session to “flood” their feet with cutaneous and proprioceptive input that can be processed and assimilated with the movement strategies facilitated during their corrective exercise program. In either case, there is no way to separate out tissue and joint mobilization from cutaneous stimulation; all happen simultaneously.

    A rock garden can be any shape or size as long as the foot fits into it. Ours is made out of plywood and two by fours. The most important aspect of a rock garden is that the rocks are confined and not given the opportunity to slide around very much, if at all.

    If the goal is to increase the tactile stimulation to the soles of the feet, we will also use balance pods. The balance pod is dome shaped, about 6 inches in diameter and has raised plastic protrusions. These protrusions provide very specific points of tactile stimulation to any area of the foot in contact with the pod. Clients can stand with each foot on a pod. Because of the dome shape and conforming surface of the pods, the joints of the foot can be taken through movements that are not consistent with flat ground.

    Our studio has traditional mat flooring that our clients will exercise on barefoot or in socks. Since the foot is only stimulated through motion on this surface and not through variable pressures or unpredictable foot placement, the rock garden and pods fill that need. Clients are encouraged to spend time barefoot or minimalist outdoors on natural surfaces to stimulate the foot regularly. The same advice applies to anyone with continuous exposure to man-made surfaces.

    Liability issues, as well as concerns regarding hygiene and safety, may keep us from going completely barefoot when we want to. As an alternative to going barefoot, minimalist shoes provide an opportunity to appropriately challenge foot function in our bodies’ best interests.

    Reviewing the research on barefoot walking versus shod (shoes), we see that the foot strike does not shift to the mid-foot and forefoot the way it does with running. As a result, when seeking the benefits of minimalist or barefoot training, we must be cautious when we extrapolate the impact on walking and everyday use based on running-specific research. The modern adult foot has probably not been exposed to the variable terrain and minimal foot coverings that our ancestors experienced. Removing a client from the support of shoes after decades of wearing them should follow a progressive exposure to surfaces other than those that are flat and man-made. When an environment conducive to foot variability is not present, the fitness professional can minimize the risks and maximize the benefits of the foot by providing an appropriate stimulus such as the rock garden described above.


    References

    Altman, A. & Davis, I. (2011, May). Comparing Barefoot Running to an Altered Strike Pattern in Shoes. Medicine & Science in Sports & Exercise, 43(5): 59.

    Beach, P. (2010). Muscles and Meridians: The Manipulation of Shape. Philadelphia, PA: Churchill Livingstone.

    Benjamin, M. J. (2009). The fascia of the limbs and back – a review. Anatomy: 1-18.

    Eskofiera, B., Krausb, M., Worobetsa, J., Stefanyshyna, D., Nigga, B. (2011, Feb.) Pattern classification of kinematic and kinetic running data to distinguish gender, shod/barefoot and injury groups with feature ranking. Computer Methods in Biomechanics and Biomedical Engineering.

    Hamilla, J., Russella, E., Grubera, A., & Millera, R. (2011). Impact characteristics in shod and barefoot running. Footwear Science, 3(1).

    Hetsroni, I., Finestone, A., Milgrom, C., Ben-Sira, D., Nyska, M., Mann, G., Almosnino, S. & Ayalon, M. (2008, January). The Role of Foot Pronation in the Development of Femoral and Tibial Stress Fractures: A Prospective Biomechanical Study. Clinical Journal of Sport Medicine, 18(1): 18-23.

    Khamis, S. & Yizhar, Z. (2007). Gait & Posture, 25: 127–134.

    Lieberman, D.E., Daoud, A.I., Geissler, G.J., Wang, F., Saretsky, J., Daoud, Y.A. & (2011, Published ahead of print). Foot Strike and Injury Rates in Endurance Runners: A Retrospective Study. Medicine & Science in Sports & Medicine. Retrieved from http://journals.lww.com/acsm-msse/Abstract/publishahead/Foot_Strike_and_Injury_Rates_in_Endurance_Runners_.98750.aspx.

    Rothbart, B. (2006, November/December). Journal of the American Podiatric Medical Association, 96(6).

    Sacco, I., Akash, P. & Hennig, E.M. (2010, Feb. 3). A comparison of lower limb EMG and ground reaction forces between barefoot and shod gait in participants with diabetic neuropathic and healthy controls. BMC Musculoskeletal Disorders, 11: 24.

    Stecco, C., Macchi, V., Porzionato, A., Morra, A., Parenti, A., Stecco, A., Delmas, V. & De Caro, R. (2010). The Ankle Retinacula: Morphological Evidence of the Proprioceptive Role of the Fascial System. Cells, Tissues, Organs, 192(3).

    Vincent, K.R., Vincent, H.K., Seay, A.N., Lamb, K.M., Greenberg, S., Conrad, B.P. (2011, May). Effect of Running and Walking in Barefoot and Shod Conditions on Gait Parameters in Trained Runners. Medicine & Science in Sports & Exercise 43(5): 60.

    Warburton, M. (2001, Dec.). Barefoot Running. Sport Science.

Life’s Balancing Act on the Foot by Dr. Doug Stewart

Thursday, February 10th, 2011

In 1971 I was just out of college and had moved to Eugene, Oregon, “running capital of the world,” to run. As an undergrad at the University of Hawaii I had won several state track titles, but had been significantly hampered by injuries, and I still wanted to see how good I could become.

It was Bill Bowerman’s last year as the University of Oregon coach, and the next year he would be the U.S. Olympic coach and founded Nike.

Consistent with my history I soon was injured in Oregon, this time with a heel spur/plantar fasciitis. Two Olympians, Steve Prefontaine (5K) and Mike Manley (steeplechase) showed me how to tape my foot which immediately got better, and surprisingly, my hip pointer (pain at the top of my pelvic bone) also went away. At the time I didn’t see the full significance of this, but it did start me thinking about how my foot, my foundation, affected the rest of my body.

I have come to recognize that most aches and pains are related to biomechanics. In this article I discuss what you can do about avoiding injuries, and especially about the foot’s role in avoiding them, the flip side of injury being efficient mechanics.

Two main ingredients make up mechanical health: good posture, and moving in a full connected way from the center of your body. A third, variety, helps you achieve the first two.

At a recent convention, the hot discussion was whether good foot posture, or good pelvic posture, was more important. That’s like asking, is it better to drink water or eat food? Good posture includes the whole body.

Nevertheless, I focus on footbeds/orthotics that address the foot’s posture, a “necessary and not sufficient” part of the puzzle, and leave the rest to people like Anthony.

The foot is your base of support, and in order to be balanced, the foot must be balanced. Imagine building a house on an unstable foundation.

Although the foot is of particular importance, it is also uniquely difficult to balance because many of the foot’s bones are horizontal. While you can stack/nicely balance/ the bones in the rest of the body on top of one another, you cannot do that with the feet. In order to maintain their arch shape, the bones must be tightly held together, or the foot will collapse.

There are several soft tissue structures, namely the muscles, fascia and ligaments, which might do this.

Muscles can usually hold the arch up for a short time when you’re standing still and the forces are small. For example, if you weigh 100 pounds, the force on each foot is 50 pounds. It gets tougher when you walk however, when forces increase to 120 pounds, and extraordinarily more difficult when you run and the forces are 350 pounds. The bottom line is that muscles are not up to the task of providing good foot posture when you either stand for a longer period of time, or run. Indeed, muscles are designed to control and cause motion, and not be so involved in posture. If they do become too involved in posture, they become tight and sore.

Among the more common muscles that become tight from holding up the arch are the two hip flexors (Psoas major, Iliacus) and the Piriformis. Although they are external rotators, with the foot on the ground they lift up the arch. Tight hip flexors are associated with low back pain, and a tight Piriformis is associated with sciatic pain.

Fascia and ligaments are designed for postural support. It is their job to hold the arch up.

Fascia has the mechanical characteristic of being “plastic,” meaning that it adapts over time to what you ask it to do. Fascia is everywhere (the gristle in meat), and although it can support you in good posture, it often gets stuck supporting you in a hunched-over posture, making standing up straight more difficult. Typically it takes several months to change the length of fascia so that one day you might say “wow, standing up straight is not so difficult.”

Ligaments hold bones together, allowing movement while supporting structure. Their job is to limit joint distention and they become injured if stretched beyond a narrow range. Unlike muscles which actively contract, ligaments merely react to stretch, returning to their original position.

Because of their poor blood supply, ligaments are difficult to heal, which is why when you hurt your ankle, you often hope you break a bone, rather than stretch a ligament. Bones heal, often becoming stronger than they were originally, whereas stretched ligaments often remain longer, leaving you with a less stable joint.

When slowly stretched, as occurs over time, ligaments also become longer. When foot ligaments are longer, arches are flatter and your foundation is less aligned.

You might have inherited longer ligaments, or over time you might have lengthened your ligaments by exposing your foot to flat, hard surfaces. Since the foot adapts to the surface upon which you place it, by walking or running barefoot (or in minimalist shoes with no support), on a flat hard surface, you are asking your foot to become flatter. Our feet are not designed to function on these man-made surfaces, rather they are designed for randomly challenging, softer, supportive surfaces like pine needle covered forest paths strewn with rocks and roots; these surfaces keep your feet healthy.

The exception is if you have inherited longer ligaments and a flatter foot, in which case even the best environment won’t keep you healthy.

The consequence of a flatter foot, one that has poor posture, is the greater likelihood of many injuries, including injuries to the foot itself such as bunions, neuromas, plantar fasciitis and heel spurs, as well as to the Achilles, calf, shin, knee, groin, hip and low back. The ubiquitous plantar fasciitis, for example, is associated with excessive pulling on the plantar fascia (when the foot flattens, it also lengthens). There are many reasons behind this, including a tight calf and a rotated pelvis, but usually the primary risk factor is longer ligaments.

In that case it becomes necessary to complement the ligaments with a footbed that holds up the arch, creating good foot posture, which allows the muscles to do what they are designed to do, which is to move your body. How important the footbed is will depend on how misaligned you are without it. The longer your ligaments, the more misaligned you are, and the more time you want to spend being supported by a footbed.

Of course it is also important to deal with the other risk factors such as the problematic calf and pelvis; however that is not so much my business, nor is it the subject of this article.

I was also asked to comment on minimalist shoes, such as the Vibram five finger shoe, since they are somewhat the rage these days.

Under no circumstances that I can think of, will your feet be healthy if you walk or run barefoot for any period of time on man-made hard, flat surfaces. This includes minimalist shoes, which allow you to function as if you were barefoot.

I agree that shoes have become too cushioned and insulate us from our environment. Nevertheless, some of us tried the experiment of minimalist shoes back in the late ‘60s, when we used to run in black canvas Keds with a minimalist crepe rubber sole. Our feet lost some of their arch and spring, and we are suffering from that abuse today.

Of course, at the time we had young bodies, didn’t know any better, and loved our Keds. But I also remember my excitement in the early ’70s when I wore my first cushioned shoe, a Tiger (now Asics) Cortez, designed to compensate for the hard roads. Intuitively I sensed that the hardness of roads was part of the problem.

You will be able to run successfully in a minimalist shoe if you stick to softer, supportive, randomly changing surfaces, and if you have inherited sufficiently strong ligaments to maintain good foot posture. Otherwise, you’re asking for trouble.

I am also occasionally asked if footbeds make your muscles lazy. After reading this, you will realize the answer is no. Footbeds complement ligaments to achieve good posture. They don’t do the work of muscles. On the contrary, good foot posture allows the muscles to work in a more balanced, efficient way.

Doug Stewart, Ph.D. (biomechanics), went to college on a track scholarship, often trying to run 100 miles a week, and often getting injured. His injuries and a desire to be more efficient motivated him to address his mechanics, which as it turns out are human mechanics, and common to most of us☺. He makes footbeds, and can be reached for comments by emailing Dougstewart2@cox.net.