The subject matter of the present invention relates generally to spiked track shoes, and in particular, to such track shoes made on a straight last and having rear spikes positioned behind the heads of the overlying metatarsal bones of the wearer's foot.
The present track shoe is made on a straight last having a last axis which bisects the heel or calcaneous bone and extends through the second metatarsal head. This last axis corresponds to the natural weight bearing line or line of leverage of the foot as it pivots on the ankle or talus bone. As a result of this straight last and the improved spike placement, the track shoe of the present invention is more comfortable, reduces injury and provides greater running efficiency by giving more forward thrust for a given amount of force applied by the foot than previous track shoes. The track shoe of the present invention minimizes stress and deformation of the foot and thereby reduces injury.
Previously it has been proposed to make conventional street shoes on straight last, such as the shoe shown in U.S. Pat. No. 2,034,243 of Maxwell granted Mar. 17, 1936. However, this has not been done heretofore with spiked track shoes. Furthermore, the above-mentioned patent positions the last axis incorrectly relative to the wearer's foot, since such axis passes between the first and second metatarsal heads, rather than through the second metatarsal head in the manner of the present invention. While not critical for street shoes, the proper location of the last axis is extremely important for optimum performance of a track shoe. Previously, track shoes have positioned their rear spikes under the joints between the metatarsal and phalange bones, as shown in U.S. Pat. No. 2,902,780 of Bellew granted Sept. 8, 1959, as well as in other positions, including positions ahead of such joints or between such bones. This prior spike placement is inefficient because it has been found with the present invention that maximum forward thrust can only be achieved by locating the rear spikes behind the heads of the overlying metatarsal bones.
The track shoe of the present invention provides a pair of rear spikes behind the heads of the overlying first and fifth metatarsal bones and positions such rear spikes along a straight line which intersects the straight last axis at an obtuse angle greater than 102.degree. and in the range of about 102.degree. to 115.degree.. As a result, such angle is substantially the same as the angle formed between the last axis and the line intersecting the metatarsal heads of the first and fifth metatarsal bones, although of course, this latter angle varies somewhat for different individual's feet. This enables the present shoe to bend more easily along the joints between the metatarsals and the phalanges where the foot flexes naturally, which is not possible with the spikes positioned under such joints as in U.S. Pat. No. 2,902,780. It has also been found that a third rear spike should be positioned behind the underlying third metatarsal head but ahead of the line connecting the rear-most pair of spikes. U.S. Pat. No. 3,327,411 of Roberts, granted June 27, 1967, is of interest because it discloses a football shoe having cleats, two of which are positioned behind the metatarsal heads but are followed by additional cleats including a longer cleat beneath the arch of the foot and three other cleats placed beneath the heel. This cleat arrangement is used to enable body weight to be transferred from the heel to the toe of the foot more efficiently which, of course, is not true in a track shoe since it has no spikes beneath the heel or arch areas of the foot.
USPTO Backgrounds
USPTO Backgrounds