A sole structure for an article of footwear comprises a sole plate that includes a forefoot portion with a foot-facing surface. 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 side wall in the forefoot portion. The first notch is configured to be open when the forefoot portion of the sole plate is dorsiflexed in a first portion of a flexion range and closed when the forefoot portion of the sole plate is dorsiflexed in a second portion of the flexion range greater than the first portion.