Q: What is the difference between an arch support and an orthotic?
A: This depends largely on how you define ‘arch support’ and orthotic’, so I will provide some definitions and answer your question based on these. An orthotic, referred to here as a functional orthotic, is designed to modify the function of your foot. These are custom-made from semi-rigid materials and prescribed for your feet and individual biomechanics. An assessment of your foot biomechanics and specific running needs is made, and then a mold of your foot is taken on which the device will be built. When all these factors are taken in account, semi-rigid functional orthotics are comfortable to wear and usually only cause irritation or pain if they are improperly prescribed or made, or the runner doesn’t follow wearing instructions correctly. Functional orthotics are usually posted or angled in such a way that the biomechanics of your foot is intentionally modified and/or improved.
Under the definition provided here, arch supports are not designed to alter foot biomechanics; they solely provide support for the arch of the foot. This support tends to stabilize the arch and the joints in the middle of the foot. Arch supports can be very comfortable and assist with many injuries such as heel pain. Because it is possible to buy arch supports ‘off-the-shelf’ and not ones prescribed by a doctor/therapist, it can be difficult to find the arch support that fits your foot correctly. Whether a runner needs an arch support, a functional orthotic or neither should be determined on an individual basis.
Dr. Nick Brown
Dr. Brown is a postdoctoral researcher in the Department of Biomedical Engineering at The University of Texas.
