Abstract: A prosthetic foot device includes an elongated continuous cantilever-spring, extending from an attachment section coupleable to a stump of an amputee to a toe section at a toe location of a natural foot. The cantilever-spring is elastically deformable under a load to store energy as the amputee steps onto the cantilever-spring and to release energy as the amputee steps off of the cantilever-spring. A cam is pivotally coupled to the cantilever-spring at a pivot. A resistance arm is coupleable to the stump of the amputee, and extends to a displaceable section engaging the cam. A lever arm is attached to the cantilever-spring and engages the cam. The cam operatively inter-couples the cantilever-spring and the resistance arm to elastically deform the resistance arm along with the cantilever-spring to collectively store more energy than the cantilever-spring alone.

Abstract: A prosthetic foot with an adjustable ankle includes an upper portion coupled to a socket of an amputee. A lower portion is adjustably coupled to the upper portion, and is attached to a foot member with heel and toe sections. A movable coupling is disposed between the upper and lower portions, and includes a displacement member slidably coupled to a displacement track. The movable coupling allows the toe section to pivot downward and the heel section to simultaneously displace forward.

Abstract: A prosthetic foot device includes an oblique attachment. The foot device can include an elongated forefoot portion having an upper attachment section disposed at an oblique angle and attached to an oblique surface of an attachment member coupled to a limb of an amputee. The forefoot portion can extend through ankle, arch and toe sections. The ankle section can include a discrete straight section that is vertically oriented and located at a rearmost of the foot device. The attachment section can extend to a position at the first third of a length of the foot device measured from the rearmost of the foot device. The foot device can be an energy storing and releasing member during use.

Abstract: A device prosthetic foot device with variable stiffness response includes a variable energy transfer medium disposed between first and second foot members to transfer at least some energy from the second member to the first member during use. The energy transfer medium includes a variable viscosity fluid such that the variable viscosity fluid, and thus the energy transfer medium, variably transfers energy between the first and second members to vary stiffness of the prosthetic foot device. The variable viscosity fluid can include a shear stiffening material that increases in viscosity as a load or strain, or rate of loading or rate of strain, applied, or a magneto or electro rheologic fluid responsive to a magnetic or electric field.

Abstract: A variable resistance cell and method provides a variable resistance response to a load factor, such as a load, a load rate, a strain, a strain rate, a pressure, or a deflection. A variable viscosity fluid is displacable between first and second chambers of an enclosure though an orifice in response to the load factor. The variable viscosity fluid has a viscosity that is variable corresponding to the load factor to vary an ability of the variable viscosity fluid to flow through the orifice. The variable viscosity fluid can be a shear stiffening material that increases in viscosity with an increase in a load factor applied to the shear stiffening material, a magneto rheologic fluid responsive to a magnetic field, or an electro rheologic fluid responsive to an electric field. The enclosure can be compressible between first and second positions.