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Like many other podiatrists, I am growing tired of the claims from the barefoot/minimalist shoe advocates who continually make unsupported statements that foot orthoses weaken the feet and/or legs. Craig Payne has been particularly vocal in this regard and has pointed out the fact that of the only two published studies that have investigated foot and leg strength after use of foot orthoses, both of them showed an increase in foot and/or leg strength with foot orthoses, not decreased strength.
Here are the two studies:
1. Jung DY, Koh EK, Kwon OY: Effect of foot orthoses and short-foot exercise on the cross-sectional area of the abductor hallucis muscle in subjects with pes planus: A randomized controlled trial. J Back Musculoskelet Rehabil, 24(4):225-231, 2011.
Effect of foot orthoses and short-foot exercise on the cross-sectional area of the abductor hallucis muscle in subjects with pes planus: a randomized controlled trial.
Jung DY, Koh EK, Kwon OY.
Abstract
OBJECTIVE:
To prevent overuse injuries related to excessively pronated feet, the strengthening of the foot intrinsic muscles has been recommended. The purpose of this study was to examine the effects of foot orthoses and a short-foot exercise intervention on the cross-sectional area (CSA) of the abductor hallucis (AbdH) muscle and strength of the flexor hallucis (FH) in subjects with pes planus.
METHODS:
Twenty-eight subjects with pes planus were randomly assigned to the foot orthosis (FO) group or the combined foot orthosis and short-foot exercise (FOSF) group for an 8-week intervention. The CSA of the AbdH muscle and the strength of FH were assessed before and after intervention. Data were analyzed using a mixed-model ANOVA.
RESULTS:
Significant group by intervention interaction effects were observed in CSA of the AbdH (p=0.009) and strength of the FH (p=0.015). The results of the post hoc paired t-test showed that that the CSA of the AbdH muscle and the strength of the FH significantly increased after the intervention in both groups (p=0.000). The mean CSA of the AbdH muscle and the strength of FH were significantly greater in subjects in the FOSF group compared with subjects in the FO group (mean difference of FO vs. FOSF=13.61 mm(2) in CSA of AbdH muscle; 0.90 kgf in strength of FH; p=0.008).
CONCLUSIONS:
Results from this study demonstrate that foot orthoses combined with short-foot exercise is more effective in increasing the CSA of the AbdH muscle and the strength of FH compared with foot orthoses alone. Therefore, foot orthoses combined with short-foot exercise are recommended for improving strength of AbdH muscle in subjects with pes planus.
2. Mayer F, Hirshmuller A, Muller S, Schuberth M, Baur H: Effects of short-term treatment strategies over 4 weeks in Achilles tendinopathy. Br J Sports Med, 41 (7):e1-e5, 2007.
Published online 2007 January 26. doi: 10.1136/bjsm.2006.031732
Effects of short‐term treatment strategies over 4 weeks in Achilles tendinopathy
Frank Mayer, Anja Hirschmüller, Steffen Müller, Martin Schuberth, andHeiner Baur
Abstract
Background
The therapeutic efficacy of non‐surgical treatment strategies in Achilles tendinopathy (AT) has not been well clarified. Time‐consuming and costly combinations of treatment for pain, physiotherapy and biomechanical procedures are often applied.
Objective
To analyse the efficacy of single therapeutic regimens commonly used over a short period of 4 weeks.
Methods
31 male runners (mileage >32 km/week) with unilateral, untreated AT completed 4 weeks of either physiotherapy (10 treatments: deep‐friction, pulsed ultrasound, ice, sensory motor training; (P)), wearing custom fit semirigid insoles (I) or remained without treatment (control group C). Before and after treatment, all patients underwent a treadmill test and a plantar flexion strength exercise. Subjective pain (Pain Disability Index, Pain Experience Scale), as well as strength performance capacity (peak torque), was analysed (mean, 95% CI, repeated measures analysis of variance, α=0.05).
Results
Pain was reduced to <50% of the baseline value after physiotherapy or after wearing insoles (p<0.05). Individual pain reduction was >50% (25%) in 89% (100%) of subjects in I and 55% (73%) in P. Higher eccentric plantar flexion peak torques after treatment were observed in I and P.
Conclusions
Most patients with AT experience a reduction in pain after only 4 weeks of differentiated, non‐surgical treatment consisting of physiotherapy or semirigid insoles.
Craig Payne and Gerald Zammit, from LaTrobe University in Melbourne, Australia, also did a study on changes in digital flexor strength which showed no significant change in foot muscle strength after wearing foot orthoses (actually they showed a non-significant increase in foot muscle strength after wearing foot orthoses). This study is currently unpublished.
Quote:
Foot orthosis use does not affect muscle strength
Craig Payne & Gerard Zammit
Department of Podiatry, School of Human Biosciences, La Trobe University, Melbourne, Australia
Foot orthoses are widely used in clinical practice to treat pathologies associated with what is assumed to be excessive pronation of the rearfoot. However it is not uncommon to come across unsupported statements in the lay press or from alternative health practitioners that foot orthotics or foot supports should not be used as they will, for example “act as a crutch” or “weaken the muscles that support the arch”. As there is no data on the effects of foot orthotics use on muscle strength, the aim of this project was to determine toe plantarflexion strength in subjects prior to the use of foot orthoses and again after 4 weeks of use.
Subjects were recruited from a teaching clinic who were issued with foot orthoses for symptoms that were assumed to be due to excessive pronation of the foot. The force required to plantarflex the toes of the left foot was measured using a specially designed platform. Subjects stood on a raised platform which was at a hinged part at the level of the lesser metatarsophalangeal joints, but not at the first metatarsophalangeal joint. The hinged part was held level by a force gauge. Subjects were instructed to maximally plantarflex the toes against the platform, while the examiner held their hand over the metatarsal heads to prevent them being elevated. The force gauge measured the plantarflexor force in Newton’s. The subjects were asked to lean against the wall behind them, so as not to lean forward or bend the knee when plantarflexing the lesser toes. Previous work had shown this testing method to be reliable. This test was considered to measure the strength of the intrinsic muscles and the flexor digitorum longus muscles. The test was conducted 5 times, with the mean used for the analysis. The trial was repeated at the 4 week review of the foot orthoses. The Wilcoxon signed ranks text was used to analyse the difference.
Sixteen subjects were recruited (mean age: 44.5 (±16.3); 5 male; 11 female). The mean follow up was 4.5 (±0.8) weeks. The mean plantarflexion strength of the lesser toes at baseline was 37.3 (±14.9)N and at follow‐up it was 40.2 (±16.3)N (p=0.23).
This study has shown that there was no decrease in muscle strength after the use of foot orthoses for 4 weeks, giving no reason to be concerned with unsupported statements that foot orthoses can weaken muscles.
The results need to be interpreted in the context of the relatively short follow‐up of 4.5 weeks and it may have been too soon to detect any weakness, however, the trend was for an increase in strength (but not statistically significant), perhaps suggesting that a longer follow up may not have shown any weakness developing.
In addition, in a recent lecture on barefoot and minimalist shoe running, a very well known researcher on barefoot running compared wearing shoes and/or orthoses to being the equivalent of wearing a "neck brace", showing a photograph of a patient wearing a neck brace to describe how traditional running shoes and foot orthoses somehow weaken the feet. I found this lecturer's mechanical analogy of comparing a foot orthosis or a shoe to a neck brace to be very interesting, but also a very poor mechanical analogy. In fact, this same researcher coauthored a very nicely done research study in 2003 on foot orthosis kinetics and kinematics which compared runners with knee pain running in Root type orthoses to a Blake Inverted orthoses. This study found no change in running kinematics with the more "controlling" Blake Inverted orthoses. Certainly, if foot orthoses did truly "brace the foot" like a neck brace, then the research would have shown a reduction in range of motion of the foot during running, which it did not.
All the scientific research evidence done over the past half century points to the fact that foot orthoses do not "brace" the foot, but rather they change the magnitudes, temporal patterns and plantar locations of ground reaction forces acting on the plantar foot during weightbearing activities. There is simply no scientific evidence that foot orthoses braces the foot to restrict physiologic motions of the foot. However, there is plenty of research to support the fact that foot orthoses not only are therapeutic but also can decrease pathologic forces and moments acting on the foot and lower extremity that can provide a very valuable therapeutic option for many individuals who, otherwise, without foot orthosis treatment, could very well, over time, develop weakness in their feet and lower extremity due to relative inactivity from their mechanically-based foot and/or lower extremity pain.
Foot orthoses are not "braces that weaken the feet and legs". Rather, foot orthoses are "high tech foot guidance systems" that guide the foot and lower extremity which, in turn, reduces abnormal and pathologic internal joint forces and moments, improves gait function and heals many painful mechanically-based pathological conditions of the foot and lower extremity.
We must be vigilant and vocal about these facts as foot health professionals who have taken an oath to ethically treat the feet and lower extremities of the people of our communities. We must speak up loud and speak up frequently about these issues, if, for no other reason, that by accepting the task of protecting the foot health of individuals of our communities we have also accepted the responsibility of preventing our community from being negatively influenced by the misinformation being spread currently by the barefoot and minimalist shoe advocates who insist on misinterpreting research or just plainly making things up that meets their confirmation bias and their agenda.
If we don't educate the public as to what the scientific evidence shows in this regard, then who will?
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
Craig Payne and Gerald Zammit, from LaTrobe University in Melbourne, Australia, also did a study on changes in digital flexor strength which showed no significant change in foot muscle strength after wearing foot orthoses (actually they showed a non-significant increase in foot muscle strength after wearing foot orthoses)
The increase in strength was not statistically significant, so we reported it as no change. Also the study has been criticized as it was only a 4 week follow up, but i would have thought that if they did actually weaken muscles we would have at least started to see a decrease in strength by 4 weeks if they did weaken them. We did actually follow-up participants as 3 months, but only could get a small number of them to return so did not report the 3 month follow-up data. In those that did return, the muscle strength was still the same as at baseline.
I mentioned in another thread that I have been looking into the use of "braces" and muscles strength and its hard to find any data. Either there isn't much or I just using the wrong search terms - more often that not, the search query's that I use returns nothing or too many abstracts to manually browse.
I did find two studies on the use of knee braces in knee OA and they both showed an increase in quadriceps strength!
I found one study on back braces and muscle activity that the authors made a conclusion that did not appear to be supported by the data - there was no change in EMG activity of the muscles, but they made some sort of nonsensical conclusion about proprioception.
I was sent one study on the use of ankle braces that showed no changes in EMG activity of the peroneal muscle ---- can we assume if EMG is activity the same, then muscles will not get weaker:
Quote:
Use of an external ankle support over an entire
volleyball season does not induce neuromuscular changes in
peroneus longus dynamic restraint following sudden inversion
perturbation as measured by short latency responses and EMD.
This study appears to support athletic trainers, clinicians, and
coaches in continued use of external supports for mechanical
and functional stability throughout the season.
....so while I can see the logic behind 'braces' weakening muscles, that is not even what the data is showing (even though I admit, there may be other data that I can not find).
I did find two studies on the use of knee braces in knee OA and they both showed an increase in quadriceps strength!
The irony of these studies to a recent thread (closed) with a certain barefoot advocate just makes me all warm and fuzzy inside
__________________
"If we all worked on the assumption that what is accepted as true is really true, there would be little hope of advance." - Orville Wright
Here is a study that showed an increase in isokinetic quadriceps strength of 16% after wearing an OA knee brace for 12 months.
Matsuno H, Kadowaki KM, Tsuji H: Generation II knee bracing for severe medial compartment osteoarthritis of the knee. Arch Phys Med Rehabil. 78(7):745-9, 1997.
Quote:
Arch Phys Med Rehabil. 1997 Jul;78(7):745-9.
Generation II knee bracing for severe medial compartment osteoarthritis of the knee.
Matsuno H, Kadowaki KM, Tsuji H.
Source
Department of Orthopaedic Surgery, Toyama Medical and Pharmaceutical University, Japan.
Abstract
OBJECTIVE:
To investigate the clinical efficacy of the Generation II (G II) knee brace, a newly developed knee orthosis, on patients experiencing severe medial compartment osteoarthritis (OA) of the knee.
DESIGN:
Case series.
SETTING:
A national medical and pharmaceutical hospital in Japan.
PATIENTS:
Twenty primary OA subjects (excluding those with secondary OA), all older than 55 years of age and experiencing only knee joint problems, were selected according to their ability to walk more than 500 meters independent of support. These patients had arthritis in both knees and no less than one half of normal joint space remaining as revealed by roentgenogram studies. The more severely affected side was selected for bracing.
INTERVENTIONS:
For 12 months, each patient wore a G II knee brace on the affected knee on a daily basis, removing it only at night. To evaluate the effects of G II OA brace alone, additional use of new oral drugs or any other treatment was prohibited from 1 month before application of the G II OA brace and throughout the trial period.
MAIN OUTCOME MEASURES:
Clinical efficacy was evaluated using the Japan Orthopaedic Association's knee scoring system. X-ray evaluation was performed with patients standing on one leg. A dynamometer was used to evaluate isokinetic quadriceps muscle strength. The center of gravity was measured using an X-Y recording. Clinical evaluation was performed every 2 months thereafter. Final evaluation was at 12 months.
RESULTS:
Nineteen of the 20 patients answered that they experienced significant pain relief. Knee pain scores on walking increased from 18.0 to 21.5 and on ascending and descending stairs increased from 12.8 to 15.8. The femorotibial angle decreased in 12 of the patients, and the mean angle decreased from 185.1 degrees before application to 183.7 degrees with the brace on at the final observation period. In addition, isokinetic quadriceps muscle strength increased from an average of 36.8 Nm to 42.8 Nm for all patients. In 17 patients, quadriceps muscle strength increased, while it decreased in 2 and remained the same in 1. Finally, lateral movement of the center of gravity decreased compared with before G II application in all patients.
CONCLUSION:
G II bracing is a beneficial treatment for severe medial OA of the knee.
Here is a study that demonstrated an increase in hamstring strength after six months of wearing a valgus unloader knee brace.
Hurley ST, Hatfield Murdock GL, Stanish WD, Hubley-Kozey CL: Is there a dose response for valgus unloader brace usage on knee pain, function, and muscle strength? Arch Phys Med Rehabil. 93(3):496-502, 2012.
Quote:
Arch Phys Med Rehabil. 2012 Mar;93(3):496-502. Epub 2012 Jan 12.
Is there a dose response for valgus unloader brace usage on knee pain, function, and muscle strength?
School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada.
Abstract
OBJECTIVE:
To examine whether there was a dose response for valgus unloader brace wear on knee pain, function, and muscle strength in participants with medial compartment knee osteoarthritis.
DESIGN:
In this single-group study, participants with medial compartment knee osteoarthritis were followed for approximately 6 months.
SETTING:
Recruitment was conducted in the general community, and testing was performed at a university laboratory.
PARTICIPANTS:
A convenience sample of patients (N=32) who were prescribed a valgus unloader brace agreed to participate, met the inclusion criteria, and completed the baseline data collection. Twenty-four participants (20 men, 4 women) completed baseline and follow-up collections.
INTERVENTION:
Participants wore their valgus unloader brace as needed.
MAIN OUTCOME MEASURES:
Knee extensor, flexor, and plantar flexor strength was tested at baseline and follow-up. Participants filled out Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Medical Outcomes Study 36-Item Short-Form Health Survey questionnaires to assess pain and function. Self-selected walking velocity and stride length were objective measures of function. Brace usage (dose) and activity (step count) were recorded at least 4 days/week for the study duration.
RESULTS:
Positive relationships existed between brace wear usage and percent change in step count (r=.59, P=.006) and percent change in hamstrings strength (r=.37, P=.072). At follow-up, there was significant improvement in hamstrings strength (P=.013), and trends toward improvements in WOMAC pain (P=.059) and WOMAC function (P=.089).
CONCLUSIONS:
Our results indicate that greater brace use may positively affect physical activity level, but there was minimal effect of brace wear dosage on lower-limb muscle strength. Only knee flexion showed a positive relationship. Our finding of no decreased muscle strength indicates that increased brace use over a 6-month period does not result in muscle impairment.
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
Hi Kevin
Good summary!
When I see anyone describing orthoses as 'braces' or 'splints' that stop foot motion then I view it is as a sign that they have a very low level understanding of the mechanics of the feet and foot orthoses.
Therefore-
Quote:
In addition, in a recent lecture on barefoot and minimalist shoe running, a very well known researcher on barefoot running compared wearing shoes and/or orthoses to being the equivalent of wearing a "neck brace", showing a photograph of a patient wearing a neck brace to describe how traditional running shoes and foot orthoses somehow weaken the feet. I found this lecturer's mechanical analogy of comparing a foot orthosis or a shoe to a neck brace to be very interesting, but also a very poor mechanical analogy. In fact, this same researcher coauthored a very nicely done research study in 2003 on foot orthosis kinetics and kinematics which compared runners with knee pain running in Root type orthoses to a Blake Inverted orthoses. This study found no change in running kinematics with the more "controlling" Blake Inverted orthoses. Certainly, if foot orthoses did truly "brace the foot" like a neck brace, then the research would have shown a reduction in range of motion of the foot during running, which it did not.
.... is a very surprising story!
Did you use 'this person's' 2003 study this during your debate???
Now having said this, I have a couple of questions for the floor-
Is it theoretically possible that a foot orthosis can weaken the foot???
My personal view is that a well designed foot orthosis shouldn't weaken the foot because it will optimise function.
An analogy-
Is a person lifting weights using good technique going to be weaker than a person trying to lift a weight with bad technique and failing??
Are foot flexors functioning within an optimal functioning zone* going to be weaker than flexors being loaded beyond their physiological capacity??
I know it is possible to have a negative effect from a foot orthosis... weaken the foot though??? Undecided.
Thoughts?
*made up term describing the fact that a muscle's ability to generate force varies across its ROM combined with mechanical advantage variations that come with different foot morphologies...
__________________
Craig Tanner
Podiatrist ASPETAR-
Qatar Orthopaedic and Sports Medicine Hospital
Doha
QATAR http://www.aspetar.com/
Now having said this, I have a couple of questions for the floor-
Is it theoretically possible that a foot orthosis can weaken the foot???
My personal view is that a well designed foot orthosis shouldn't weaken the foot because it will optimise function.
An analogy-
Is a person lifting weights using good technique going to be weaker than a person trying to lift a weight with bad technique and failing??
Are foot flexors functioning within an optimal functioning zone* going to be weaker than flexors being loaded beyond their physiological capacity??
Optimize foot function is term that has been misused and poorly defined. We probably should not use the term after a "because" because unless there are several paragraphs before it describing what foot function is. I agree with the weight lifting analogy though.
I can see how an orthotic with a medial heel skive or a shoe with a dual density midsole that is firmer medially can make the posterior tibial muscle work less hard. However, if someone is running over a mile, I would maintain that their posterior tibial muscle is getting a workout no matter what they have on their feet. Some feet more than others, but feet are different. But the idea that working out in shoes and or orthotics prevents muscle activity is ludicrous.
I can see how an orthotic with a medial heel skive or a shoe with a dual density midsole that is firmer medially can make the posterior tibial muscle work less hard. However, if someone is running over a mile, I would maintain that their posterior tibial muscle is getting a workout no matter what they have on their feet. Some feet more than others, but feet are different. But the idea that working out in shoes and or orthotics prevents muscle activity is ludicrous.
OK devil's advocate: lets say we run with and without orthotics and kinematics remain largely unchanged, yet the kinetics do change such that the external supination moment is increased and the internal supination moment is decreased with the orthoses in situ. Sure, the posterior tibial muscle is getting a work-out in both situations, but it's getting a bigger workout without the orthoses (if the posterior tib. is at least in part responsible for the internal supination moment). Assuming, that the posterior tibial is not dysfunctional and functioning within its zone of optimal stress (ZOOS) in both situations, which situation should result in greater strengthening of this muscle?
OK devil's advocate: lets say we run with and without orthotics and kinematics remain largely unchanged, yet the kinetics do change such that the external supination moment is increased and the internal supination moment is decreased with the orthoses in situ. Sure, the posterior tibial muscle is getting a work-out in both situations, but it's getting a bigger workout without the orthoses (if the posterior tib. is at least in part responsible for the internal supination moment). Assuming, that the posterior tibial is not dysfunctional and functioning within its zone of optimal stress (ZOOS) in both situations, which situation should result in greater strengthening of this muscle?
A foot orthosis may decrease the contractile activity of a muscle which may indeed cause the muscle-tendon unit to be subjected to less tension stress on it during activity. The big question is whether this reduction in muscle-tendon stress is a positive or negative factor for the individual.
If the muscle-tendon unit is being over-stressed (i.e. near the plastic range of the stress-strain curve), then certainly having a foot orthosis that reduces its activity is in the best interest for the health of the individual. However, realistically, I don't think that this reduction of muscle-tendon stress would cause a "weakness" in the muscle-tendon unit and may, in fact, over time, produce a more strong muscle-tendon unit by allowing greater capacity for muscle work with reduced risk of injury.
If the muscle-tendon unit, however, is not being over-stressed and is well within the middle of the elastic range and physiologic levels for that muscle, and the foot orthosis reduces the contractile activity of the muscle by, 15% for example, will this 15% reduction in the contractile activity of this one muscle over time be even detectable clinically as a weakness in the muscle or cause any functional incapacity? I don't think so. There is a big difference between being within the normal ranges of muscle strength for an individual and having "muscle weakness".
The term "muscle weakness" means that the muscle strength is below a normal range of strength values for a certain group of individuals of a certain sex and age. "Muscle weakness" does not mean that the person went from being from in the upper 33% of normal muscle strength to the middle 33% of normal muscle strength.
Therefore, for the barefoot and minimalist shoe advocates to continue to claim that foot orthoses "weaken feet" is: 1) not supported by any scientific evidence, and 2) not a physiologically realistic scenario that would be expected to occur in an individual that can perform their daily activities without gait or functional abnormalities or pain during these activities.
Simply put, the curious suggestion by the barefoot and minimalist shoe advocates that foot orthoses somehow weaken feet is neither physiologically nor biomechanically coherent and not supported by a shred of scientific evidence. In my opinion, those individuals that make these types of unsupported statements show how little they understand about the biomechanical nature of foot orthoses and the complex physiology of the human neuromuscular system.
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
.... is a very surprising story!
Did you use 'this person's' 2003 study this during your debate???
Unfortunately, I have heard this individual make these "shoes and foot orthotics are like neck braces" claims before. Didn't have time to bring up the 2003 study but was able to point out that the cost of my orthoses was much less than the cost of their "gait retraining program" which was quoted as costing $640.00 for eight sessions.
When I pointed out that their $640.00 gait retraining sessions was more costly to the patient than their complaints about my "$400.00 foot orthotics".....I got a big laugh from the audience.
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
All of your replies (and those of all other respondents) bemoan the difficulty of educating the public and (sadly) the medical profession at large about foot mechanics and, perhaps with much greater difficulty, bringing acceptance and action on our experience.
I am particularly disappointed with my results since early on in practice of bringing acceptance to the fact that podiatry is of premier importance in pediatrics. The idea that foot problems are primarily those of youth and not of old age has been and, I'm sure, still is at best hard to swallow by the public and medical community alike. They continue to take symptoms as problems. Mert Root had repeatedly discussed this phenomenon. At one point he told us that his practice had been 75% pediatric.
Prevention, prevention, prevention!!!
After all, how can Bill Orien's "magic shovels" be anything other than the venerable arch support!! (BTW, anyone know how Bill is? I've heard nothing of him for decades.)
Regards to all...including those from Down Under who still amaze me by their standing on their heads!!
Simply put, the curious suggestion by the barefoot and minimalist shoe advocates that foot orthoses somehow weaken feet is neither physiologically nor biomechanically coherent.
Kevin, I tend to agree, but I think the changes observed in EMG patterns with orthosis in-situ, and the hypothetical I provided above should provide a potential mechanism for weakening of muscles in association with foot orthoses which is both physiologically and biomechanically coherent.
Unless, the foot orthosis don't change the peak stress magnitude within the muscle units, but rather the timing of these... Or indeed, increase the magnitude of stress within certain muscles (which will result in an increase in strength).
Like many other podiatrists, I am growing tired of the claims from the barefoot/minimalist shoe advocates who continually make unsupported statements that foot orthoses weaken the feet and/or legs. Craig Payne has been particularly vocal in this regard and has pointed out the fact that of the only two published studies that have investigated foot and leg strength after use of foot orthoses, both of them showed an increase in foot and/or leg strength with foot orthoses, not decreased strength.
Here are the two studies:
1. Jung DY, Koh EK, Kwon OY: Effect of foot orthoses and short-foot exercise on the cross-sectional area of the abductor hallucis muscle in subjects with pes planus: A randomized controlled trial. J Back Musculoskelet Rehabil, 24(4):225-231, 2011. 28 subjects divided into 2 groups with neither exercise only or sham controls Level I-II Evidence at best
2. Mayer F, Hirshmuller A, Muller S, Schuberth M, Baur H: Effects of short-term treatment strategies over 4 weeks in Achilles tendinopathy. Br J Sports Med, 41 (7):e1-e5, 2007. 31 pateints (10 in each group), the study lasted 4 weeks and it tested the Tendo Achilles for strength, a muscle engine that I would not want to use as a gauge positive gauge if stronger after the study.
Level I-II at best
Craig Payne and Gerald Zammit, from LaTrobe University in Melbourne, Australia, also did a study on changes in digital flexor strength which showed no significant change in foot muscle strength after wearing foot orthoses (actually they showed a non-significant increase in foot muscle strength after wearing foot orthoses). This study is currently unpublished. and therefore has no value in this discussion
All the scientific research evidence done over the past half century points to the fact that foot orthoses do not "brace" the foot, but rather they change the magnitudes, temporal patterns and plantar locations of ground reaction forces acting on the plantar foot during weightbearing activities. There is simply no scientific evidence that foot orthoses braces the foot to restrict physiologic motions of the foot. However, there is plenty of research to support the fact that foot orthoses not only are therapeutic but also can decrease pathologic forces and moments acting on the foot and lower extremity that can provide a very valuable therapeutic option for many individuals who, otherwise, without foot orthosis treatment, could very well, over time, develop weakness in their feet and lower extremity due to relative inactivity from their mechanically-based foot and/or lower extremity pain.
We must be vigilant and vocal about these facts as foot health professionals who have taken an oath to ethically treat the feet and lower extremities of the people of our communities. We must speak up loud and speak up frequently about these issues, if, for no other reason, that by accepting the task of protecting the foot health of individuals of our communities we have also accepted the responsibility of preventing our community from being negatively influenced by the misinformation being spread currently by the barefoot and minimalist shoe advocates who insist on misinterpreting research or just plainly making things up that meets their confirmation bias and their agenda.
Once again, Who Is We?
Thia paragraph is all opinon and has no place in the discussion.
Worse, IMHO, calling those who do not agree with you "making things up" when their theories and opinions should be reviewed and judged "without evidence, right Dr Payne reflects your bias in these matters.
If we don't educate the public as to what the scientific evidence shows in this regard, then who will?
no, if you had your way
Kevin:
1. When you state "like many other podiatrists", how many DPM's do you think you represent?
You certainly don't represent me and many others that I come in contact with in America.
2. When you state "All the scientific research evidence done over the past half century points to the fact that foot orthoses do not "brace" the foot, but rather they change the magnitudes, temporal patterns and plantar locations of ground reaction forces acting on the plantar foot during weightbearing activities, not that I disagree but just how much scientific research evidence is there?
3. As an EBM advocate, like you, I find the evidence that you present to be rather weak, one sided (your side), personally selected and overrated.
IMHO, it does not override or trump the expert opinions and experiential clinical successes that live with a differing take on this and many other subjects that you wish to control.
If you had any more or stronger evidence, we would all know about it.
What do you think of the work of Dr. Munson and the US Army countering your claims to some extent?
3. Strengthening the plantarflexion power of the triceps, for me, means that primary muscles are in fact weakening or becoming inhibited and an equinus pathology is being promoted.
Summarily, this goes against your argument because important muscles are being disused that forces the t. Achilles to compensate.
4. Citing stronger digital flexors, once again, reflects a compensatory weakness of the first ray rocker necessitating compensating activity in the 2-3-4-5 rockers, which to me is pathological.
This goes against your argument.
5. Combining therapies (Orthotics +) without controls doesn't prove that it was the orthotics that was the positive entity.
Level II evidence at best.
6.Picking one or two muscles, randomly to test (abductor hallucis? there's an important muscle in running).
Why weren't more tested in these studies?
7.Where is your evidence involving P. Longus, P. tibial, A tibial, FHL, etc?
These muscles, if strengthened by orthotics with study, would mean something for me.
Taking all the anecdotal, expert experience and clinical successes of increasing numbers of practitioners and sending them under the bus with the short term, small patient numbered, poorly conceived evidence you site is simply unfair and not a valid argument IMHO.
and, most importantly,
without defining "The Orthotic" and then extrapolating that to mean "orthotics" produces more than enough error in these studies and has no meaning when it is applied to "all orthotics" being fabricated and dispensed to the foot suffering public.
Whose orthotics, what orthotics.
Please give us your definition of an "Orthotic" for research purposes.
Patients, for years and years, coming to me with "orthotics" that have failed to correct a diagnosis of "overpronation", (whether they are "overpronated" or not), test poorly for P. longus power and motor control.
Additionally, these same patients, when tested barefoot and upon their "Orthotics" almost always exhibit poorer 1st ray function in their orthotics rather when compared to barefoot (the devices are applying a supination moment to the 1st metatarsal) making them potentially harmful.
IMHO, accepting the pittance of evidence that you refer to over and over as a reason to make your expert opinions more important than those differing with them is using EBM as a battering ram against those with opposing views unfairly.
Dennis
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So, Dennis, we have 3 studies that you don't like all saying the same thing and no study showing the opposite, so you go into a silly rant because it happened to be Kevin who started the thread.
You claim to be a proponent of evidence based medicine, yet anyone can go back and read everything that you have written on functional foot typing and neoteric biomechanics and that you don't have a shred of evidence for it. You comment above that Paynies study is irrelevant because its not published. As your FFT is not published in a peer reviewed journal, then that also makes it irrelevant. You can't have it both ways.
I think the evidence is clear. There are 3 studies, and yes they have some issues with them, but they are all saying the same thing. Dennis, you have no studies to back up what you are saying. You loose.
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You claim to be a proponent of evidence based medicine, yet anyone can go back and read everything that you have written on functional foot typing and neoteric biomechanics and that you don't have a shred of evidence for it. . .........You lose.
I want to enthusiastically nominate this quote from DaVinci as quote of the year for 2012. Classic!!
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
So, Dennis, we have 3 studies that you don't like all saying the same thing and no study showing the opposite, so you go into a silly rant because it happened to be Kevin who started the thread.
You claim to be a proponent of evidence based medicine, yet anyone can go back and read everything that you have written on functional foot typing and Wellness biomechanics and that you don't have a shred of evidence for it. You comment above that Paynies study is irrelevant because its not published. As your FFT is not published in a peer reviewed journal, then that also makes it irrelevant. You can't have it both ways.
I think the evidence is clear. There are 3 studies (only 2, Craig's is yet unpublished as are many works of mine that you are discounting. You can;t have it both ways), and yes they have some issues with them, but they are all saying the same thing. Dennis, you have no studies to back up what you are saying. You loose.
Agreed.
But the real question here as to your apparent contest whose rukes you control and define, what do I loose? The entire battle?
Does the evidence of these two weak studies give you the winning hand in the argument?
If you have weak and flawed evidence and I have no evidence then the bulk of the argument lives on anecdote, opinion, clinical experience and success rates in practice.
DaVinci, are these two weak and flawed studies valuable, important, worthy of the extrapolation that it serves as valid EBM as per Sackett's definition to control the argument.
Dennis
If the evidence were so available and applicable, why would Craig and others be scrambling to define "What to do when there is no evidence"?
I'm sick of hearing it too. Even the guys and gals doing the fitting at some SHOE STORES try to get me to cast off my own orthotics! I'll ask them if they realize you're talking to the person who Rx'd them too? And they've NEVER lived in my feet, so how can they know that "strengthening your muscles better"?
WHAT are they saying to my patients???
Seriously. If you want to remain in pain, give up the orthotics and try and continue with any level of activity that will result in muscle strength improvement around that problem joint/structure. Try. I can poke you with a cattle prod while we're at it; pain is negative reinforcement and a major barrier to a healthy active lifestyle.
Do Foot Orthoses Weaken Feet/Legs?
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