A sole structure (10, 10A, 10B) for an article of footwear comprising: a midsole body (14, 32) having a proximal surface and a distal surface; wherein the midsole body (14, 32) has a first set of holes extending through the midsole body (14, 32) from the proximal surface to the distal surface, a second set of holes extending through the midsole body (14, 32) from the proximal surface to the distal surface, and a cleft extending partway through the midsole body (14, 32) between the first set of holes and the second set of holes; wherein 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, and wherein: the midsole body (14, 32) is a polymeric foam and includes an interior portion, and a skin that covers the interior portion and extends along each hole of the first set and each hole of the second set from the proximal surface to the distal surface; the skin has a first density; and the interior portion has a second density less than the first density such that the midsole body (14, 32) has a greater compressive stiffness under a force of the midsole body (14, 32) along the center axis of each hole than transverse to the center axis, or than at an oblique angle to the center axis. a midsole body (14, 32) having a proximal surface and a distal surface; wherein the midsole body (14, 32) has a first set of holes extending through the midsole body (14, 32) from the proximal surface to the distal surface, a second set of holes extending through the midsole body (14, 32) from the proximal surface to the distal surface, and a cleft extending partway through the midsole body (14, 32) between the first set of holes and the second set of holes; wherein 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, and wherein: the midsole body (14, 32) is a polymeric foam and includes an interior portion, and a skin that covers the interior portion and extends along each hole of the first set and each hole of the second set from the proximal surface to the distal surface; the skin has a first density; and the interior portion has a second density less than the first density such that the midsole body (14, 32) has a greater compressive stiffness under a force of the midsole body (14, 32) along the center axis of each hole than transverse to the center axis, or than at an oblique angle to the center axis. the midsole body (14, 32) is a polymeric foam and includes an interior portion, and a skin that covers the interior portion and extends along each hole of the first set and each hole of the second set from the proximal surface to the distal surface; the skin has a first density; and the interior portion has a second density less than the first density such that the midsole body (14, 32) has a greater compressive stiffness under a force of the midsole body (14, 32) along the center axis of each hole than transverse to the center axis, or than at an oblique angle to the center axis.