Background: The interest in the effects of foot orthoses (FO) on postural stability in elderly adults has recently increased. Arch supporting insoles placed inside the shoe to position the foot near its neutral position may affect the plantar surfaces of the feet, thereby influencing neuromuscular function. Limited reports exist on the effects on postural sway and lower limb muscle activity of arch supporting insoles. The aim of this study was to investigate whether arch supporting insoles alter postural control and lower limb muscle activity during quiet bipedal standing balance. Methods: A Footscan® balance system was used synchronously with an electromyography unit (MEGA ME 6000, Mega Electronics) to determine postural sway variables (Anterior-Posterior and Medial-Lateral ranges of centre of pressure (CoP) displacements) and amplitudes of electromyographic (EMG) activity in eight dominant lower limb muscles in 15 healthy males (63±7.8 years) under three randomised conditions: barefoot (BF), shoe only (SO) and shoe with foot orthoses (SFO). Results: In the shoe with foot orthoses (SFO) condition centre of pressure (CoP) ranges are larger than for the two other conditions (p<0.05). However in the shoe with foot orthoses (SFO) condition, no significant differences were observed in lower limb muscle activity. Conclusion: This study points at effects of inserts on balance parameters which warrant future work in the field. In particular, the effect of long-term use of such inserts needs to be clinically evaluated.
