A midsole or insole device for a shoe includes a first variable stimulation mechanism positioned to interface one of the metatarsal heads and the heel and a second variable stimulation mechanism positioned to interface a lateral aspect of the foot between the fifth metatarsal head and the heel. During gait-related activities, the first variable stimulation mechanism produces stimulus of an intensity greater than the second variable stimulation mechanism. At least one of the first variable stimulation mechanism and the second variable stimulation mechanism comprises two bonded layers including a resilient stimulating upper layer and a less resilient stimulus-enhancing lower layer. The upper layer includes a plurality of holes that pass through the entirety of the upper layer, and the lower layer includes a plurality of equally spaced upwardly facing projections aligned substantially perpendicular to an upper surface of the upper layer.