Do foot orthoses change lower limb muscle activity in flat-arched feet towards a pattern observed in normal-arched feet?

One of the hypothesised mechanisms by which foot orthoses obtain their clinical effect is by influencing muscle activity, however previous studies have reported highly variable findings. The aims of this study were to; (i) investigate whether modified prefabricated and customised FOs influence lower limb muscle activity, and if so, (ii) whether they optimise or “reverse” the abnormal lower limb muscle activity previously observed in people with flat-arched feet. Thirty young asymptomatic adults with flat-arched feet were recruited.