Sole structure for an article of footwear with side wall notch and nonlinear bending stiffness

A sole structure for an article of footwear comprising:

• a sole plate that includes a forefoot portion with a foot-facing surface;
• wherein:
• the sole plate has at least one side wall extending upward from the foot-facing surface;
• the at least one side wall has a first notch in an upper periphery of the at least one side wall in the forefoot portion of the sole plate;
• the first notch includes a rounded base, a forward face and a rearward face, the rounded base disposed below the forward face and the rearward face and connecting the forward face and the rearward face, both of the forward face and the rearward face extending from the upper periphery to the rounded base, and the forward face and the rearward face being spaced apart from one another when the sole plate is in an unflexed, relaxed state;
• the first notch is configured to be open between the upper periphery and the rounded base when the forefoot portion of the sole plate is dorsiflexed in a first portion of a flexion range and closed by contact of the forward face with the rearward face when the forefoot portion of the sole plate is dorsiflexed in a second portion of the flexion range greater than the first portion;
• a distance across the first notch from a lowest extremity of the forward face to a lowest extremity of the rearward face when the sole plate is in the unflexed, relaxed state is less than a distance across the first notch at the rounded base below the lowest extremity of the forward face and the lowest extremity of the rearward face;
• and
• the first notch is open at the rounded base in both the first portion of the flexion range and the second portion of the flexion range.