Interpod Research Articles: Summary Sheet

Title/Author Information Conclusion/Outcome
Title/AuthorSupporting the foot
Craig Payne
Latrobe University. School of Human Biosciences
InformationA summary of the current literature on why foot orthoses support the foot and the lower limb and assist in injury prevention. The review defines “poor foot posture” and how to measure this. Conclusion/Outcome
  • Poor foot alignment increases the risk of injury for tissue damage.
  • Foot orthoses decrease the risk of injury by changing foot alignment.
  • Foot orthoses have a positive impact on pain and foot deformity.
  • Shock absorbing insoles can reduce foot pain.
  • Interpod devices change foot alignment, support the midfoot and absorb shock.
Title/AuthorPlantar fascia grooves in foot orthoses
Craig Payne
Latrobe University. School of Human Biosciences

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InformationA summary of the current literature on the activation of the windlass mechanism and the effect of plantar fascia grooves in orthoses. Conclusion/Outcome
  • A plantar fascial groove in the orthoses improves comfort for individuals with a prominent plantar fascia.
  • The groove can potentially lower the force needed to establish the windlass mechanism.
  • The most optimal position for the plantar fascial groove to activate the windlass mechanism is both in the midfoot and further forward in the orthoses shell.
Title/AuthorResistance of the foot to supination
Craig Payne, Matthew Oates and Shannon Munteanu
Latrobe University. School of Human Biosciences
InformationA summary and review of the concept and effectiveness of the supination resistance test used in determining foot orthoses prescriptions in podiatry. Conclusion/Outcome
  • Determining the level of supination resistance of the foot has a significant use as a clinical decision making tool to assist in prescribing foot orthoses.
  • Mechanical devices to measure supination resistance have been found to be both reliable and repeatable.
  • Body weight has been correlated with supination resistance.
  • Manual testing of the supination resistance may be more practical for a clinical environment, however this test is very subjective.
  • Foot posture is mildly correlated to supination resistance.
  • Harder supination resistance results were correlated with those who have the subtalar joint tip over sign.
  • Vasyli and Formthotics devices did not significantly change the position of the calcaneus.
Title/AuthorImproved gait efficiency
Craig Payne
Latrobe University. School of Human Biosciences

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InformationThe body’s center of mass vertical trajectory during gait was assessed in an individual before and after the use of Interpod Orthoses treatment implementation. Conclusion/Outcome
  • The use of the Interpod orthoses significantly improved the individual’s COM alignment to that of the body’s ideal COM trajectory.
Title/AuthorComparison of preform orthoses
Craig Payne
Latrobe University. School of Human Biosciences

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InformationThe study measured the change in frontal plane position of the calcaneus using a number of prefabricated orthoses. The study compared the Interpod Control Tech Flex orthoses in the three available arch heights (4, 6 and 8 degrees) with the Interpod Control Tech Soft (4 and 6 degrees) and Interpod Slim Tech Soft device. The study then compared these against Vasyli, Formthotics, Prothotics, Orthopro, a 6 degree high density EVA wedge and a rubber arch cookie. Conclusion/Outcome
  • Interpod orthoses were more effective in realigning the foot than Vasyli and Formthotic.
  • Interpod orthoses were as effective in realigning the foot as the Orthopro, Prothotic and the 6 degree heel wedge.
Title/AuthorPrefabricated foot orthotics decrease internal tibial rotation during hopping in females
Houglum, PA., & Carcia, C.R.
Kristen McMaster Human Movement Laboratory, Duquesne University, Pittsburgh

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InformationThe study investigated the influence of orthotics on minimizing the amount of tibial rotation present during decelerating activities and the consequential relationship this has with stress and strain on the anterior cruciate ligament and injury risk. The study also investigated the relationship between males and females and internal tibial rotation. They used the Interpod semi rigid orthoses, which included a 6 degree rearfoot varus post. Participants GRFs and tibial rotation moments were tested during landing and hopping tasks. Conclusion/Outcome
  • The study found that females internally rotate more than males during hopping and landing.
  • A prefabricated foot orthoses is capable of decreasing internal tibial rotation in females during hopping.
Title/AuthorLarsa Technical Report
Peter Roy (technical officer)
NZ leather and shoe research association
InformationThe study investigated the energy absorption characteristics in the as received condition and ageing treatments. The study compared Interpod (new device), Interpod (old device), Formthotics Ultimate foot comfort and Vasyli custom heat moldable orthotics for customized prescription. Conclusion/Outcome
  • The Interpod (Polyurethane) devices performed better than the EVA Vasyli and Formthotic devices in all tests (compression, absorption and hydrolysis).
  • Interpod Polyurethane devices have 30% more shock absorption than the EVA devices.
Title/AuthorEffects of a plantar fascial groove in a foot orthotic on the windlass mechanism
Craig Payne
Latrobe University. School of Human Biosciences

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InformationThe study investigated the force required during static stance to establish the windlass mechanism in identically shaped foot orthoses with and without a plantar fascial groove. Conclusion/Outcome
  • The windlass mechanism enables the foot to support itself.
  • A standard foot orthoses with a plantar fascial groove is more effective in lowering the force required to activate the windlass mechanism when comparing to an identical orthotic without a plantar fascial groove. 
  • Lowering the force required to enable the windlass mechanism would facilitate gait and stability of the foot and improve gait efficiency.
Title/AuthorComparison of the semi-rigid prefabricated foot orthoses and custom made foot orthoses
Craig Payne
Latrobe University. School of Human Biosciences

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InformationThe study investigated the patients perceptions of the fit and comfort between a custom foot orthoses and a prefabricated foot orthoses. The study used polypropylene custom devices from a laboratory and compared these to the Interpod prefabricated Control Tech Flex incorporated with a heel post. Interpod devices were chosen for patients on the closest matched arch height to the custom device. Conclusion/Outcome
  • No difference was found in participants perceived comfort and fit between Interpod prefabricated devices and custom made foot orthoses.
  • This study does not support the use of Custom foot orthoses over prefabricated devices based on comfort.
Title/AuthorComfort fit and control of Prefabricated foot orthoses
Craig Payne
Latrobe University. School of Human Biosciences
InformationInvestigated the perceived comfort and control of the rearfoot from prefabricated foot orthoses available in the Australian market. The study compared Interpod, Vasyli, Formthotics, Prothotics, Spenco, Alphathotic, Dr Scholl, Orthoheel and Footsteps. Conclusion/Outcome
  • Subjects perceived the Interpod full length device as the most controlling.
  • Subjects perceived the Interpod ¾ length orthotic to be the most effective device in changing the position of the rearfoot.
  • Subjects perceived the Interpod slimfit (dress shoe) orthotic to be the most effective device in changing the position of the rearfoot.
  • Interpod orthoses are perceived as more controlling and this was not correlated with a poorer level of fit or comfort.
Title/AuthorThe response of the foot to prefabricated orthoses of different arch heights
Craig Payne, Matthew Oates and Alison Mitchel
Latrobe University: School of Human Biosciences

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InformationThe study investigated the static stance response of the foot to prefabricated foot orthoses in different arch heights. The study compared the Interpod Control Tech Flex orthoses in the three available arch heights (4, 6 and 8 degrees) with the Interpod Control Tech Soft (4 and 6 degrees) and Interpod Slim Tech Soft device. Conclusion/Outcome
  • The Interpod devices significantly changed the static position of the foot in the frontal plane, the position of the calcaneus in the direction of inversion and significantly increased arch height.
  • FPI was not found to be an indicator of how much the calcaneal angle can change, however it was related to how much the navicular height can change.
Title/AuthorPoron orthoses absorb mechanical stress
James Birke & James Foto
InformationThe study investigates the strengths and weaknesses of PORON on providing shock absorption and protection to the foot. The study compared the effect that different thicknesses of soft materials (such as poron) have on pressure reduction. Comparison Tests conducted with and without orthotics: RCSP, Navicular Height, skin lines, FPI, and Supination resistance. Conclusion/Outcome
  • Poron has been recognized as one of the most popular materials used in the fabrication of foot orthoses.
  • Poron resists bottoming out from repetitive compressive/shear stress and is superior to other materials such as Spenco and Plastazote. 
  • The research found that the harder the material is, the less accommodating it is (poor choice for neuropathic high risk patient).
  • If the material is too soft it will bottom out with each step unless reinforced with a strong orthoses shell.
  • A mid strength material is more likely to have a positive effect on plantar pressures than one which is too soft or too hard.