Abstract: A running shoe comprises an upper and a midsole attached to the upper, the midsole having a front portion corresponding to a forefoot and a rear portion corresponding to a heel. The front portion of the midsole may have one or more notches which may increase the flexibility of the midsole. One or more flex grooves may extend through the midsole to similarly increase the flexibility of the midsole. A flex groove may be associated with a notch via a notch and a flex groove being associated with a channel. The flex groove may have void regions in which the flex groove extends entirely through the midsole to define a void therein. The void regions may increase the movability of forefoot pods defined by the relationship of flex grooves and how they may intersect each other and extend through each other.

Abstract: A running shoe comprises an upper and a midsole attached to the upper, the midsole having a front portion corresponding to a forefoot and a rear portion corresponding to a heel. The front portion of the midsole may define a toe spring of at least 40 mm and a plurality of flex grooves, the plurality of flex grooves including one or more horizontal flex grooves and one or more longitudinal flex grooves, the horizontal flex groove(s) extending in a lateral to medial direction of the running shoe and allowing the front portion of the midsole to lie flat in response to application of less than 15 pounds of force against the toe spring, the longitudinal flex groove(s) extending in a front to back direction of the running shoe. The rear portion of the midsole may have a flat bottom that is narrower than the upper.