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Relationship between explosive muscle strength and medial longitudinal arch of the foot.
Lizis P, Posadzki P, Smith T. Foot Ankle Int. 2010 Sep;31(9):815-22.
Quote:
BACKGROUND: There has been a suggested link between muscle strength and arch type of the foot. However, a distinct cause and effect dependence has yet to be established. The purpose of this study was to compare the outcomes from selected explosive strength tests with different arch heights.
MATERIAL AND METHODS: The medial longitudinal arch (MLA) was measured using a Clarke's angle method. Five hundred seventy-four subjects (n = 574) participated in this study and were divided into three arch height groups and three muscle strength groups, respectively. To evaluate the association between longitudinal arch of the foot with the explosive power of lower limb muscles, Chi-square (χ(2)) test was used.
RESULTS: Arch heights were not significantly related to explosive muscle strength.
CONCLUSIONS: Arch measurement was ineffective in accounting for the observed variability in the explosive strength among young adults.
CLINICAL RELEVANCE: This data may be useful in evaluating patients with painful flat feet and any strength deficits they may have.
I thought that barefoot running is supposed to make muscles stronger and improve the height of the arch. As this study showed no correlation between strength and arch height, I guess that is another myth we can cross of the list of claims made by the barefoot runners.
I thought that barefoot running is supposed to make muscles stronger and improve the height of the arch. As this study showed no correlation between strength and arch height, I guess that is another myth we can cross of the list of claims made by the barefoot runners.
You right. Another myth bites the dust.
Actually I have been giving a bit of thought to the claims by barefoot runners that their arch "improves" as the "muscles strengthen"...as we know from the above research that this can not be the case (and clearly most of those in the barefoot running community have no idea of the different factors that actually control the height of the arch).
What else could explain what they think they are seeing?
We know the the range of 1st MPJ dorsiflexion is probably greater running barefoot than in shoes ... what does that mean? ... it means the windlass mechanism is probably working to a greater extent running barefoot. Imagine a runner with a forefoot supinatus and they are now using their windlass more as they are now running barefoot... probably what happens is some of the supinatus corrects because of the greater first ray plantarflexion from the more effective windlass .... that could easily account for an increase in arch height from barefoot running and it has nothing to do with muscle strength!
__________________ Craig Payne
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I haven't got access to the full text of the above study but I would of thought that a repetetive strength test to measure muscle function over a sustained period would be a better indicator of instrinsic muscle strength. How does a one off explosive strength test relate to everyday activity?
Muscle strength wont directly affect so arch hight. But the fact that when you do strength exercise the muscles gain bulk and tighten. the tightening of the muscles then could appear to reform the arch. If the flexibility is still there then the muscle has laxity. If a body builder did nothing but small ranges of motion with his weights, the muscle bulk would reduce his range of motion, and the muscle would tighten from the fact he is not stretching them in any way. This the same idea with the foot. The only way the arch may reform though is if the foot muscles are bulking and losing flexibility. And remember that explosive power is different to strength. Power is a mixture of strength and speed. So you need to know what you are testing for. The next point is that tibialis posterior make up the arch. So would it not be more beneficial to do a strength test on that muscle and compare it to arch height?
When barefoot running the muscles will be used to there maximum, and also with no foot support surely the joints will be put through a greater range of motion. the foot will therefore be working harder and strengthening muscles, but at the same time the muscle are being stretched further than if they had support in a shoe.
Lets not jump to the conclusion that running barefoot doesn't strengthen intrinsic foot muscles. This study simply evaluated lower leg muscle strength and found that there is no correlation to arch height. How does this fail to support the contention from the barefoot running community about foot strengthening from barefoot activity? Seems to me it has nothing to do with it.
I have a patient who on several occassions requires some foot manipulation....and this was because of a TN joint fracture he suffered in a rock climbing accident years ago. He is otherwise fine. He has hiked the highest peak in New Hampshire, Mt. Washington (6288 ft) barefoot on multiple occassions. His arch muscles are so developed and his feet are so strong, that it occurred to me on his initial visit that the majority of the patients we see in our clinics daily are "deconditioned". Barefoot running is clearly not for everyone...but for a select few....it would seem that the benefits would outweight the risks. For those multitudes of "deconditioned" patients...foot strengthening may help....and certainly not hurt.
Howard - I do not deny for one minute that barefoot running has the potential to lead to stronger muscles. My issue is with the unsupported claims you frequently read by barefoot runners that it is this increase in muscle strength that leads to the higher arch profile that many of them are claiming they see in themselves. The study quoted above would appear to refute those claims and I offered an alternative theoretical explanation for in above.
__________________ Craig Payne
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In my travels, I have seen people walking poolside in the Vibram 5 finger shoes. Frightening what they could potentially do to themselves. We agree that the hype has the potential to injure many.
I believe that Steven Robbins publised quite some time ago, and did measure arch height in a group who ran barefoot over a summer and found an increase. He was of the opinion that by having the body react to noxious stimuli from the ground, reflexive responses would stabilize the foot. One quote from this article "cushioned shoes anesthesized feet", always resonated well with me. The barefoot concept did not originate with Born to Run.
I agree with your contention that more MTP joint dorsiflexion, the higher arch height will ultimately become as form must follow function. I have also seen the reduction in supinatus when MTP joint dorsiflexion is encouraged with a foot orthotic, as well in substantial increases in the general mobility of all foot joints.
If we model the longitudinal arch of the foot as a load-sharing structure, which I just lectured on in San Diego this last weekend, then from superficial to deep, the loads in the longitudinal arch are shared by the following tensile load-bearing structures:
Therefore, it seems clear to me the plantar instrinsics have signficant potential to mechanically cause a rearfoot dorsiflexion moment and a forefoot plantarflexion moment (i.e. a longitudinal arch raising moment), but certainly don't act by themselves to do so.
Another complicating factor is that as the intrinsic muscles hypertrophy with increased strength, even though the arch-raising effect for these muscles increase, the plantar longitudinal arch contour may actually decrease due to the increased mass of muscles in the arch. When we start to discuss this topic of "longitudinal arch height", we must be very clear if we are talking about the osseous contour of the longitudinal arch, or the plantar soft tissue contour of the longitudinal arch.
I have also examined the feet of habitually barefoot individuals and certainly their intrinsic musculature seem different than other types of feet. However, I have also examined some very strong-looking feet in individuals who nearly always wear shoes but who are involved in running and jumping sports.
The argument could be made that if you are able to run faster and longer and more frequently in the optimum shoe compared to what you could run while only barefoot, then the reduction in running speed, duration and frequency while barefoot would weaken the muscles of the feet when compared to when the athlete is wearing shoes. Maybe wearing running shoes actually strengthens the feet versus running barefoot due to this factor?
I am not impressed in any way by the argument that all shoes weaken feet, but certainly there are some styles of shoes that could do so. Remember, "shoes" means anything that covers the feet and this means a huge number of shoe design permutations (including Vibram FiveFinger Shoes). However, I would imagine that unless the individual can walk and do activities all day while barefoot, that there be only a minor strengthening benefit from being barefoot, while significantly increasing the risk of injury when locomoting on the wide variety of surfaces encountered in our environment.
Interesting discussion.
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
From the 2012 ACSM Conference: The Relationship Between The Toe Exercises And The Medial Longitudinal Arch
Takashi Shiro****a, Toru Fukubayashi
Quote:
PURPOSE:The toes play an important role, yet the toe flexor strength is poorly understood. We have been researching clinical and electromyogram (EMG) studies about the toe exercises we developed. However, the relationship between the toe exercises and the medial longitudinal arch (MLA) was unclear. The purpose of this study is to examine the relationship between the toe exercises and MLA.
METHODS:The subjects were 35 feet of 21 participants(11 males 17 feet, 10 females 18 feet), whose mean age was 23.1±4.5 years old. The participants performed three toe exercises and the towel gathering exercise. The three toe exercises were isotonic contractions (10 times) of the great t toe flexor, 2nd-to-5th toe flexors and 3rd-to-5th toe flexors.
All subjects randomly performed the three toe exercises and the towel gathering exercise. Before and after each exercise, we assessed MLA using the navicular drop test (NDT)Brody developed.
This study was performed with the consent of the Ethics Committee for Human Research of Waseda University and Gumma Paz College.
For statistical analysis we performed Repeated ANOVA using IBM SPSS Statistics19. Results were considered significant at values of p<0.05.
RESULTS:NDT of before the training was 4.50 mm (within the range of the normal value).NDT of the towel gathering was 5.20mm, showing significant drop in comparison with before exercise. Also, in the great toe exercise, it was 5.39mm, showing a significant drop in comparison with before (p<0.05). In the 2nd-to-5th toe flexors and 3rd-to-5th toe flexors exercises, these were 3.16mm, 3.28mm respectively, those exercises showed significantly no drop in comparison with before(p<0.05).
CONCLUSIONS:The towel gathering and the great toe flexor exercise significantly decreased MLA. In regard to the great toe flexor exercise, the tendency was stronger. On the other hand, the exercises of 2nd-to-5th toe flexors and 3rd-to-5th toe flexors increased MLA.
This study has limits, as it was not possible to get rid of influence of fatigue. We consider that it is necessary to study the toe exercises we developed by longitudinal method research.
__________________ Craig Payne
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Muscle Strength and Arch Height
Linear Mode
