Comparison between two different thicknesses in thin mechanical stimulations on the plantar arch: effects on the gait analysis and balance control

Previous studies showed that the proprioceptive system of the feet can be effectively stimulated by a thin plantar insert with influences on gait cycle, balance control and ocular organization. The most common thicknesses used are 1.5 mm and 3.0 mm but there is no evidence regarding a greater functional impact of the 3 mm thickness of plantar insert compared to the 1.5 mm.

The aim of this study is to evaluate if two different plantar insert thicknesses (1.5 mm and 3 mm) can produce different effects on gait cycle and balance control.

Twenty-four healthy adults were recruited and randomly assigned to two groups: a group with a 1.5 mm-thick plantar insert, and a group with a 3 mm-thick plantar insert. The trials foresaw two experimental conditions: without a plantar insert (Baseline) and after a fitting period with a plantar insert carried out on a treadmill (After 15’).

Mixed-model ANOVA revealed significant differences between the 1.5 mm-thick and the 3.0 mm-thick plantar inserts, both in the gait cycle and in the balance control variables, and baropodometric variables.

This research highlighted that the choice to use plantar inserts with different thicknessed is not related to the resulting effects of greater or lesser magnitude but must depend on the functional results to be obtained. In fact, 1.5 mm-thick insoles seem to have a greater functional impact on the stabilometric and plantar pressure variables, while 3.0 mm-thick insoles seem to have a greater functional impact in the gait cycle variables.