Challenging Balance: Can Foam Insoles Serve as an Alternative to Pads?

This study aimed to evaluate (1) how different support surface properties challenge balance and (2) whether foam insoles can reproduce similar effects to foam pads. Twenty healthy young adults stood on 5 support surfaces (ie, no foam, firm foam, and soft foam, and 2 insoles made from each foam) under 2 stance types (bipedal vs unipedal). The elliptical area, path length, and mean velocity of center of pressure were recorded. Elliptical area was significantly larger while standing on soft foam (P = .005), and firm insoles (P = .014) compared with no foam, during bipedal stance (1). Furthermore, all conditions, except soft insoles, produced larger path length and velocity than the no foam condition. Only the firm insoles produced an elliptical area comparable to the soft foam (P = .286), while significantly differing from the no foam and soft insoles (2). Yet, firm insoles were not similar to soft foam in terms of path length and velocity. However, no difference was found between the support surfaces in unipedal stance. These suggest that both the soft foam pad and the firm insoles challenge balance yet use distinct balance strategies. Nonetheless, firm insoles may represent a potential alternative to foam pads to challenge balance, particularly spatial dispersion, during functional tasks such as gait.