Sole or sole insert including concavely rounded portions and flexibility grooves

A footwear sole or a removable footwear sole insert, comprising:

• a heel area, a forefoot area and a midfoot area located between the heel and forefoot areas of the footwear sole or the removable footwear sole insert, wherein
• the forefoot area defines a first extent from a toe end of the footwear sole or the removable footwear sole insert towards a heel end of the footwear sole or the removable footwear sole insert,
• the midfoot area defines a second extent, and
• the heel area defines a third extent from the heel end of the footwear sole or the removable footwear sole insert towards the toe end, wherein a length of the first extent is greater than a length of the second extent, and the length of the first extent is also greater than a length of the third extent;
• a concavely rounded upper surface and a convexly rounded lower surface of the footwear sole or the removable footwear sole insert, as viewed in frontal plane cross-sections taken in the heel area, the forefoot area and the midfoot area, and in sagittal plane cross-sections taken in the heel area and the forefoot area, the concavity and convexity being determined relative to a middle portion of the footwear sole or the removable footwear sole insert between the concavely rounded upper surface and the convexly rounded lower surface of the footwear sole or removable footwear sole insert;
• a middle portion of the concavely rounded upper surface and a middle portion of the convexly rounded lower surface of the footwear sole or the removable footwear sole insert are parallel, as viewed in frontal plane cross-sections taken from proximate to a rearmost portion of the heel area to proximate a foremost portion of the forefoot area:
• a first flexibility groove located in a lateral side of the midfoot area of the footwear sole or the removable footwear sole insert;
• and
• a second flexibility groove located in a medial side of the midfoot area of the footwear sole or the removable footwear sole insert;
• and wherein:
• at least one of the first and second flexibility grooves extends from one of the lateral and medial sides of the midfoot area of the footwear sole or the removable footwear sole insert through part of an underneath portion of the footwear sole or the removable footwear sole insert located between the lateral and medial sides of the midfoot area of the footwear sole or the removable footwear sole insert;
• the convexly rounded lower surface of the footwear sole or the removable footwear sole insert extends to a sidemost extent of a lateral side of the footwear sole or the removable footwear sole insert wherein the convexly rounded lower surface terminates before the sidemost extent of the lateral side of the footwear sole or the removable footwear sole insert at a location of the first flexibility groove;
• the convexly rounded lower surface of the footwear sole or the removable footwear sole insert extends to a sidemost extent of a medial side of the footwear sole or the removable footwear sole insert wherein the convexly rounded lower surface terminates before the sidemost extent of the medial side of the footwear sole or the removable footwear sole insert at a location of the second flexibility groove.

A footwear sole or a removable footwear sole insert, comprising:

• a heel area, a forefoot area and a midfoot area located between the heel and forefoot areas of the footwear sole or the removable footwear sole insert, wherein
• the forefoot area defines a first extent from a toe end of the footwear sole or the removable footwear sole insert towards a heel end of the footwear sole or the removable footwear sole insert,
• the midfoot area defines a second extent, and
• the heel area defines a third extent from the heel end of the footwear sole or the removable footwear sole insert towards the toe end, wherein a length of the first extent is greater than a length of the second extent, and the length of the first extent is also greater than a length of the third extent;
• a concavely rounded upper surface and a convexly rounded lower surface of the footwear sole or the removable footwear sole insert, as viewed in frontal plane cross-sections taken in the heel area, the forefoot area and the midfoot area, and in sagittal plane cross-sections taken through the heel area and the forefoot area, the concavity and the convexity being determined relative to a middle portion of the footwear sole or the removable footwear sole insert between the concavely rounded upper surface and the convexly rounded lower surface of the footwear sole or the removable footwear sole insert;
• a middle portion of the concavely rounded upper surface and a middle portion of the convexly rounded lower surface of the footwear sole or the removable footwear sole insert are parallel, as viewed in frontal plane cross-sections taken from proximate to a rearmost portion of the heel area to proximate a foremost portion of the forefoot area:
• a first flexibility groove located in a lateral side of the midfoot area of the footwear sole or the removable footwear sole insert;
• and
• a second flexibility groove located in a medial side of the midfoot area of the footwear sole or the removable footwear sole insert;
• and
• the first and second flexibility grooves are the only flexibility grooves located on the medial and lateral sides of the midfoot and heel areas of the footwear sole or the removable footwear sole insert;
• and
• wherein:
• the convexly rounded lower surface of the footwear sole or the removable footwear sole insert extends to a sidemost extent of a lateral side of the footwear sole or the removable footwear sole insert except at a location of the first flexibility groove;
• the convexly rounded lower surface of the footwear sole or the removable footwear sole insert extends to a sidemost extent of a medial side of the footwear sole or the removable footwear sole insert except at a location of the second flexibility groove;
• and
• lowermost extents of the first and second flexibility grooves are at or below a lowermost extent of the concavely rounded upper surface of the footwear sole or the removable footwear sole insert and an uppermost extent of the first and second flexibility grooves are at or above an uppermost extent of the convexly rounded lower surface of the footwear sole or the removable footwear sole insert, when the footwear sole or the removable footwear sole insert is upright and in an unloaded condition.