Minimalist, what was your experience?

Once peak pronation is reached at a point 40% into the stance phase, the foot begins to supinate about the subtalar joint in order to reach a more neutral position. The transverse tarsal joint locks resulting in a more rigid foot. The now rigid foot is prepared to act as a lever for push-off with the metatarsal heads acting as a fulcrum. As the toes dorsiflex, the plantar fascia tightens locking the metatarsals, deepening the longitudinal medial arch and resupinating the foot. This process, known as the windlass mechanism, provides a stable and centered foot for efficient propulsion. The properly spaced toes of the bare foot grasp the ground while keeping the runner balanced and directing the foot forward. Unfortunately the tapered toe box found in most shoes constricts the toes and prevents their natural spacing. Also, the shoe’s toe spring – the upward tilt of the toe area visible in the side profile of the shoe – lifts the digits of the foot away from their natural flat position impeding their grasping responsibility. The instability caused by inadequate toe spacing and grasping leads to imbalances that generate compensations by the legs and upper body. Inefficient gait and possible injury result.11

Footwear modifies some of the characteristics of the propulsion phase in other ways. Several of these changes are related to the aforementioned elevated heel of the shoe. One byproduct of heel elevation is a shortening of the Achilles tendon and calf muscles. Three of the calf muscles – the posterior tibial, flexor hallucis longus and flexor digitorum longus – play important roles in the function of the arch. As these muscles become shorter, they fail to pull properly on the back of the heel thereby increasing the flattening of the arch. Pronation occurs at a time when the foot should be in a neutral position. The unnatural position of the elevated heel also disrupts the work of some tendons connected to the toes. These tendons, which originate in the lower leg, apply their pull around ankle bones above the heel to hold the toes against the ground while the body passes over them during propulsion. The raised heel leads to an imbalance in the tug of these tendons thereby interfering with efficient propulsion.11

Perhaps the greatest hindering effect of elevated heel is the loss of the involuntary stretch reflex of the Achilles and posterior lower leg muscles. This stretch reflex is designed to aid the forefoot with propulsion, yet it can only be activated if the heel comes close to the ground. The elevated heels of most available footwear, including athletic shoes, prevent this stretch reflex from occurring.11 The result is a loss of propulsive power. The runner’s body is forced to borrow power from other areas – knee, thigh, hips, trunk – to compensate for the sidelined Achilles tendon and calf muscles.12 According to podiatrist William A. Rossi, "ANY shoe with an elevated heel, even a one-inch heel, automatically places the foot at a functional disadvantage."4

Additional implications

The barefoot runner can expect reduced knee injury frequency. The association between high-heeled shoes and knee problems has been well documented. Wearing high heels, normal ankle function during gait is disrupted forcing the knee to compensate. Abnormal forces result across the patellofemoral and medial compartments, the sites of typical degenerative joint changes. Additional loads are also placed on the quadriceps muscles and the hip.13,14 Though it is not being suggested that running shoes should be classified as "high-heeled," many training shoes exhibit a sizeable heel. (A difference of approximately 1 inch is easily observed between the posterior center heel and the point on the forefoot closest to the surface on many popular training shoes.) Even these smaller heel heights can be expected to increase knee pressures to some extent.

Another reason for potentially fewer knee woes for barefoot runners can be traced to adaptations at the ankle and knee joints. Studies have shown that runners adapt to a running surface by modifying their lower leg stiffness.8,15,16 For the barefoot runner, the changes in lower extremity geometry include a decrease in knee joint stiffness and a corresponding increase in ankle joint stiffness compared to the shod runner.17 This results in the ankle becoming the site of greater impact absorption. For the shod runner, the impact absorption demand on the knee is greater. Considering that up to 30% of all running injuries are related to anterior knee pain, the adoption of barefoot running must be considered as a method for reducing knee injuries in runners.18

Barefoot runners can also expect fewer sprains of the ankle. Ankle sprains are the most common acute injury suffered by athletes. Runners who frequent trails or uneven surfaces may be especially vulnerable to this type of injury. Since nearly all ankle sprains are inversion injuries, it behooves athletes to find ways to improve their lateral stability. The best lateral stability, with mostly reduced inversion, is found in the barefoot condition. This is because a shoe’s sole increases the lever arm thus escalating torque around the subtalar joint during a stumble.19,20 Also, imperfect proprioception can cause the foot to be placed in an awkward position. Compared to being barefoot, foot position awareness has been shown to be 107.5% worse when wearing athletic footwear. The authors of this study believe, "The inescapable conclusion is that footwear use is ultimately responsible for ankle injury."21

One of the most touted benefits of today’s running shoes – the ability to provide shock absorption – also deserves a close look. Modern running footwear is well endowed with cushioning purportedly to reduce impact forces absorbed by the body. However, there exists no scientific study providing evidence that cushioning has a significant effect on in-vivo impact forces. On the other hand, there is evidence that an increase in impact forces is associated with softer shoes.22,23 Combine this evidence with the previously mentioned sensory deprivation aspect of shoe cushioning and the role of athletic footwear as a protective device must be questioned.

There is some evidence that barefoot running is less fatiguing than shod running, at least for one important muscle. A recent study looked at the tibialis anterior muscle which is responsible for dorsiflexing the foot before impact. Since the shod foot exhibits more dorsiflexion at touchdown than the bare foot, it is not surprising that electromyographic signals indicated greater muscle activity before heel-strike in the shod condition. Since this muscle activity must conclude quickly to release the forefoot, it is likely to incorporate a high percentage of fast twitch muscle fibers. Given that fast twitch muscle fibers fatigue quicker than slow twitch fibers, this important muscle will undoubtedly fatigue sooner when runners wear shoes.24

Finally, how does running economy compare between the barefoot and shod state? Oxygen consumption has been shown to be 4.7% higher while wearing shoes (approximately 700 g per pair) and running at 12 km/h.20 Reasons for this include the mass of the added footwear requiring additional energy to move the shoes through each stride, energy being absorbed by the shoe’s cushioning, and the energy expense of flexing the sole of the shoe. When these energy drags are combined with the previously detailed loss of a stretch reflex from the lower leg it becomes understandable that barefoot running is more economical.

Resources

Carrier David R. "The Energetic Paradox of Human Running and Hominid Evolution." Current Anthropology, 25 (1984): 483.

Cook, Gareth. "The Running Animal." Boston Globe, 9 April 2002: C1.

De Wit, Brigit, Dirk De Clercq, and Peter Aerts. "Biomechanical analysis of the stance phase during barefoot and shod running." Journal of Biomechanics, 33 (2000): 269-278.

Rossi, William A. "Footwear: The Primary Cause of Foot Disorders." Podiatry Management, February 2001: 129-138.

De Clercq, D., et al. "The mechanical behaviour of the human heel pad during foot strike in running: an in vivo cineradiographic study." Journal of Biomechanics, 27(1994): 1213-1222.

Robbins, Steven E. and Adel M. Hanna. "Running-related injury prevention through barefoot adaptations." Medicine and Science in Sports and Exercise, 19.2(1987): 148-156.

Kurz, Max J. and Nicholas Stergiou. "A Dynamical Systems Theory Approach to Evaluate the Influence of Shoe Hardness on Intralimb Coordination Strategies." .

Kurz, M.J. and N. Stergiou. "The Influence of Footwear and Shoe Hardness on Lower Extremity Intralimb Coordination Strategies." Proceedings of the International Society of Biomechanics’ 1999 Footwear Symposium, .

Kersting, U.G., H. Bohm, and G.-P. Bruggemann. "Internal Loading of the Lower Extremity During Running Obtained by Two Different Calculation Methods." Proceedings of the International Society of Biomechanics’ 1999 Footwear Symposium, .

Hrlejac, Alan, Robert N. Marshall, and Patria A. Hume. "Evaluation of lower extremity overuse injury potential in runners." Medicine and Science in Sports and Exercise, 32.9(2000): 1635-1641.

McClanahan, Ray. "Foot Health Information." 8 July 2003. .

Rossi, William A. "Why Shoes Make ‘Normal’ Gait Impossible." Podiatry Management, March 1999: 50-61.

Kerrigan, D. Casey, Jennifer L. Lelas, and Mark E. Karvosky. "Women’s shoes and knee osteoarthritis." The Lancet, 357(2001): 1097-1098.

Kerrigan, D. Casey, Mary K. Todd, and Patrick O. Riley. "Knee osteoarthritis and high-heeled shoes." The Lancet, 351(1998): 1399-1401.

Hardin, E.C., J. Hamill, and A.J. van den Bogert. "Adaptation of Running Kinematics to Surface and Footwear." Papers Presented at the 24th Annual Meeting of the American Society of Biomechanics, .

Smith, G. and P. Watanatada. "Adjustment of Vertical Displacement and Stiffness with Changes to Running Footwear Stiffness." .

Coyles, V.R., M.J. Lake, and A. Lees. "Dynamic Angular Stiffness of the Knee and Ankle During Barefoot and Shod Running." Proceedings of the International Society of Biomechanics’ 2001 Footwear Symposium, ``http://www.uni-essen.de/%7Eqpd800/FW2001/LITPDF/Coyles12%20doc.pdf%%.

Ounpuu, Sylvia, William B. Workman, and Peter A. DeLuca. "A Comparison of Barefoot versus Shod Running Using 3D Gait Analysis." Abstracts of the 5th Annual Gait and Clinical Movement Analysis Meeting, April 2000, .

Stacoff, Alex, Jurg Steger, Edgar Stussi, and Christopher Reinschmidt. "Lateral stability in sideward cutting movements." Medicine and Science in Sports and Exercise, 28.3(1996): 350-358.

Warburton, Michael. "Barefoot Running." Sportscience, 5.3(2001), .

Robbins, Steven, Edward Waked, and Ron Rappel. "Ankle taping improves proprioception before and after exercise in young men." British Journal of Sports Medicine, 29.4(1995): 242-247.

Shorten, M.R. "The Myth of Running Shoe Cushioning." Keynote Lecture given at the 4th International Conference on the Engineering of Sport, September 2002, ``http://www.biomechanica.com/pdfs/ISEA%20Myth.pdf%%.

Robbins, Steven E., Adel M. Hanna, and Gerard J. Gouw. "Overload protection: avoidance response to heavy plantar surface loading." Medicine and Science in Sports and Exercise, 20.1(1988): 85-92.

von Tscharner, Vinzenz, Beat Goepfert, and Benno M. Nigg. "Changes in EMG signals for the muscle tibialis anterior while running barefoot or with shoes resolved by non-linearly scaled wavelets." Journal of Biomechanics, 36(2003): 1169-1176.

Nigg, Benno M. "The Role of Impact Forces and Foot Pronation: A New Paradigm." Clinical Journal of Sports Medicine, 11(2001): 2-9.

Wright, Karen. "Watching Your Steps." Scientific American, 283.3(2000): 52+

how many would you like?

elflord wrote:

Where are "all these" minimalists with injury?

We've already had another one post in this thread. I just see them pop up fairly frequently. Usually with tarsal stress fractures and neuromas.

That's one. If you have seen these minimalist-related metatarsal stress fractures "fairly frequently" please point us to one or two of them. Shouldn't be that difficult. Unless, of course, they don't really pop up much at all.

I've been reading these threads too.

why would your foot not be able to run a few hours per week?

My foot would rather not hammer the pavement 100,000 times per week. I would rather not pound my foot without giving it rest between poundings.

elflord wrote:

why would your foot not be able to run a few hours per week?

My foot would rather not hammer the pavement 100,000 times per week. I would rather not pound my foot without giving it rest between poundings.

That's my point: why is running synonymous with "hammering the pavement"?

Example: A guy says that his body feels thrashed everytime he goes off the diving board at the local pool, and concludes that humans weren't meant to dive without adequate protection. You ask him to demonstrate and when he goes off the high dive he does a belly flop everytime. Well, no wonder he feels thrashed after about 20 of those.

Technique.

I tried this whole running in flats crap. Didn't do anything beneficial for me. Had lots of soreness in my lower legs, shin splints, tight calves, PF flared up for the first time in about a year or so, etc. Lots of stuff that just wouldn't go away until I went back to good ole trainers. Had no improvement in form from flats that everyone loves to talk about so much. All I had to do was concentrate on my form and work on not being a heel-striker. My form improved pretty quickly just from thinking about not being a heel-striker. Now I'm a mid-foot striker and I made this transition in trainers, not everyone's beloved flats (and don't try to tell me you're a fore-foot striker. This means your heels never touch the ground -- if they do, it's wasting energy since you're going toe-heel-toe every footstrike). 80mpw in flats? I do 120 in trainers and I'm pr'ing a ton. This training in flats stuff is total crap.

Training in flats will not do anything for you that you can't achieve in trainers. If you're looking for constant soreness or a stress fracture, make the move to flats today!

And now I await everyone's tired, trite explanations about why it didn't work (e.g. I "made the move too fast," or I "didn't give it enough time.")

elflord wrote:

why would your foot not be able to run a few hours per week?

My foot would rather not hammer the pavement 100,000 times per week. I would rather not pound my foot without giving it rest between poundings.

A properly functioning foot isn't supposed to "pound" or "hammer" in the first place. That is the problem.

Find a clean stretch of pavement and run barefoot on it. Does your foot pound or hammer? Of course not.

If your foot action is so screwed up and reliant upon shoes that you cannot run at all without pounding or hammering, by all means, stay away from running in flats. But a very large contingent of people find that their feet adjust quickly and they get fewer injuries, not more, when running in flats. They start to rely on the foot's own cushioning action.

There is nothing "specious" about their experiences

I've had exactly one stress fracture -- also in the metatarsal -- it came from running in full-blown trainers, only 30-40 miles a week. I never got one from doing 100+ in flats.

I know guys that put in up to 150 mile weeks in flats.

The soreness passes. Why were you sore? Could it be that your muscles and ligaments were shortened due to high heels?

Hi Barry, I've used the Brooks racer ST for several training runs up to about 90 minutes...I still go for a lightweight trainer on my long marathon training runs, unless I'm on trail. The only thing I've noticed sometimes is that my legs are a bit more tired, but its gotten better over time. I train with a buddy who always wears either the Brooks Racer ST or the old Asics DS Racer (the bright yellow one from last year), and occasionally the NB900 and sometimes xc flats like the asics 15-50. He is what most folks would call a chroic overpronater and most people would definitely try to put him in a pretty stiff stability trainer. But he's done terrifically well in the flats and light shoes so I think as long as you are careful, the transition is possible.

bringer of news wrote:

Training in flats will not do anything for you that you can't achieve in trainers. If you're looking for constant soreness or a stress fracture, make the move to flats today!

And now I await everyone's tired, trite explanations about why it didn't work (e.g. I "made the move too fast," or I "didn't give it enough time.")

Clearly it didn't do much for you. I'm sorry you were unable to do it. Many people find it works better for them, not worse. Many are able to do it without the soreness and PF you experienced. Many find that it reduces injuries. However it is you run, your body is unable to adjust to flats. It is nothing to get upset about.

That's one. If you have seen these minimalist-related metatarsal stress fractures "fairly frequently" please point us to one or two of them.

It's two actually. Dylan and the other guy. Two. Therefore, I've already pointed to "one or two of them". I found a couple more with a quick search of this board. For example, posts by "rcb" on the first page of a search for "tarsal fracture flats" should do it. Then there are a couple more in the "does training in flats lead to injury" thread, again on the first page of that search. I didn't look at all of the hits, but there are 7988 of them for you to look at if you like.

I'm glad that the letsrun.com serach engine is up there with google in its ability to search for relavant material.

What are your thoughts of the above passage on high heels, thick midsoles, and injuries?

But this doesn't even begin to get at what I'm discussing. of the issues it raises -- one of them is with footwear restricting spread of the toes, an issue with flats or regular footwear. The other part of the article addresses heel heights, but I'm all for making low-heeled trainers. But I'd also like to have some forefoot cushioning. You seem to think I'm advocating 26:12 shoes. I'm not, I'm advocating 20:12, or 22:12 or something like that.

I suffered from a stress fracture on my left tibia when switching to flats. I even cut back 15 miles/week for a smoother transition, but after eight 10-12 mile days my shin gave in.

I've always considered myself to be a fairly effecient runner and a okay runner (14:52, 30:51), but flats just weren't for me.

So what are you going to do now? Will you try wearing flats for more than speedwork, or do you prefer to stick with what you know for now?

switched to flats on the "advice" of this board.

8 weeks later, stress fracture in the right tibia (never had a stress fracture in 12 years of running, 4 @ a DI college).

took some time off, moved, got a different job. 6 month later, tried running again - ran for 5 weeks with a max of 18 miles a week and picked up a metatarsal stress fracture in the left foot.

when i do return to running, its the brooks beast for me.

What shoes did you use when you ran your personal best times? (14:52, 30:51)

Pegasus '02

elflord wrote:

What's "natural" about running 80 miles a week, almost barefoot on pavement anyway ?

What's natural about wearing shoes? ;-) jag