Do foot orthoses change lower limb muscle activity in flat-arched feet towards a pattern observed in normal-arched feet?
Authors: Murley, G.S, Landorf, K.B., and Menz, H.B (2010).
Clinical Biomechanics, 25, 728-736.
Commentary by Allan Wrigley
The use of foot orthotics in Canadian sport seems to be on the rise. There are many rational reasons for this centering on their function to help in the management of a number of lower limb issues; be that from overuse conditions, anatomical deficiency, or to help correct body positioning for athletic performance. I find that this study is interesting for two reasons; one being an explicit intent of the study and the other being a by-product of how the study was designed. The main result of the research shows that using foot orthotics altered lower limb muscle activation patterns in patients with flat-arched feet to patterns that are closer to those found in normal-arched feet individuals. More interestingly then that though, was that modified pre-fabricated (off-the-shelf) orthotics were rated as comfortable and were actually shown to have a greater positive impact on muscle activation patterns then custom made orthoses. The modifications to the off-the-shelf model simply consisted of using a heat gun to soften the insole for a better fit to the individual foot and adding a 20 degree wedge (consistent with the manufacturer’s recommendations). The custom orthotics were made from plaster casts taken by a podiatrist with 10 years of clinical experience sent to an orthotic lab. Considering the cost of custom orthoses and the time to have them made, this research paper provides some compelling evidence that a more affordable (and potentially more effective) solution can be found.