Abstract: A biochemically tuned shoe has a heel construction that provides a force-deflection response which is optimal for a particular person and a particular use. The heel construction features a main spring that is characterized by a large vertical compliance while at the same time exhibiting an extremely high resistance to a lateral shear (horizontal compliance). The main spring is preferably a coned disk spring formed of a plastic material or a vertical stack of operatively coupled coned disk springs. The main spring can be embedded in a conventionally shaped heel formed of a resilient material such as an open or closed cell foamed rubber or plastic secured to the sole of the shoe. In other forms, the heel construction is replaceably secured to the sole by a threaded stud with or without an intermediate assembly. In a preferred form, the main spring acts in cooperation with a resilient member to extend the characteristic load deflection curve of the main spring.

Abstract: A closely spaced array of modules forms an athletic playing surface characterized by a high degree of vertical compliance, an extreme resistance to lateral shear, and a high degree of uniformity of response. Each module has a laminated construction that includes a pair of stiffly resilient plates in a generally parallel, spaced relationship. One or more spacer plates and a plurality of resilient members are "sandwiched" between the plates. The lower plate is supported on a frame that allows it to flex in response to an applied force, typically the impact of a runner's foot on the upper plate. The spacer plate is configured, positioned, and secured to the upper and lower plates to mechanically couple them in a manner that, to a large degree, compensates for a non-uniformity of the deflection response of the module introduced by the frame support. The resilient members are selected and positioned to provide a substantially uniform deflection response at the upper plate.

Abstract: An extended athletic playing surface that increases running speed of an athlete performing on the surface and reduces the likelihood of injury to the athlete has a multi-layer construction. The athlete's foot impacts on an upper surface of a sheet material that has a low mass per unit area and is stiffly resilient. The upper surface is supported on either discrete "bumper pads" of a resilient material, or preferably a combination of horizontal, spaced apart supports and bumper pads. The composite structure rests on a conventional surface such as a concrete base. The composite surface is characterized by a low effective vertical mass and a composite vertical compliance that is extremely large in comparison to any comparable known athletic surface. The surface also has a high effective horizontal mass and a low horizontal compliance.