A sole structure for an article of footwear comprises a midsole body having a proximal surface and a distal surface. The midsole body has a first set of holes extending through the midsole body from the proximal surface to the distal surface, a second set of holes extending through the midsole body from the proximal surface to the distal surface, and a cleft extending partway through the midsole body between the first set of holes and the second set of holes. Center axes of holes of the first set are parallel with center axes of holes of the second set with the cleft open, and are nonparallel with the center axes of the holes of the second set with the cleft closed. The sole structure for an article of footwear further comprises a plurality of proprioceptive elements, each proprioceptive element disposed in a different hole of the first set or of the second set, and translatable relative to the midsole body along a central axis of the respective hole in a direction toward the proximal surface under a force along the central axis at a distal end of the proprioceptive element; a connecting web integral with the plurality of proprioceptive elements at either proximal ends or distal ends of the plurality of proprioceptive elements such that the connecting web and the plurality of proprioceptive elements are a single, unitary component; and in combination with a sock overlying the connecting web such that the proximal ends of the plurality of proprioceptive elements translate into a foot-receiving cavity of the sock.