Myth: Custom foot orthotics mechanically align, and/or control motion in the foot and ankle. 14 March, 2008 Dr. Rene Asselin Foot orthotics have often been viewed as a rigid shoe insert that mechanically align, and/or control motion in the foot and ankle (rigid brace). Insurance companies are one of the main culprits in perpetuating this myth! Contrary to popular opinion, custom foot orthotics DO NOT re-align joints, muscles or ligaments. Additionally, orthotics have not been shown to alter pronation. Hold on, don't throw out your orthotics or footbeds just yet!! Orthotics are now thought to work by reducing soft tissue vibration via proprioception (Nigg 2002). Orthotics seem to work by stimulating receptors in your muscles. Your muscles then react by helping to dampen vibration and control excessive muscular forces. This may be one of the reasons why it has been published that patients respond positively to orthotic therapy 70-80% of the time (Nigg, Nurse 1999). Clinically, it is not uncommon to see improvements or the resolution of symptoms (foot, ankle, knee, and lower back) when orthotics have been perscribed. Pronation and altered biomechanical function in the ankles, knees, and hips may indicate the need for orthotics therapy. However, this does not mean that the orthotics mechanically corrected the initial mechanical dysfunction! These concepts are not at all far fetched. Taping and wrapping in sports injuries are showing a similar mechanism. Rather than mechanically controlling motion the tape or wrap acts as proprioceptive input that signals the body and provides stability throught the co-activation of various local muscle groups. Athletes can contend to this since usually after 10-15 minutes of exercise the tape has loosened off to the extent that it now provide little control to motion. However, enough presence on the skin is able to stimulate surface receptors to send signals to local muscle groups. This is how researchers are attempting to explain some of the literature that is supportive for these forms of treatments. As in many things, don't be too quick in discounting the treatment, but be critical when examining the theory / philosophy underlying it. Until next friday! Dr. Rene Asselin www.synergywellnesscentre.com www.sportchiro.ca