Sole structure for an article of footwear

A sole structure for an article of footwear, the sole structure comprising:

• a midsole having a top surface, a bottom surface opposite the top surface, and a peripheral surface (i) extending between the top surface and the bottom surface and (ii) defining a first opening at a medial side of the sole structure and a second opening at a lateral side of the sole structure, the first opening and the second opening disposed in a forefoot region of the sole structure;
• an outsole including an upper surface and a ground-contacting surface formed on an opposite side of the outsole than the upper surface;
• a gap defined between the bottom surface of the midsole and the upper surface of the outsole in the forefoot region;
• and
• an insert disposed within the gap and including a first projection having a first arcuate outer surface that is visible at the medial side via the first opening and includes a first gloss unit value that is higher than a gloss unit value of the peripheral surface and a second projection having a second arcuate outer surface that is visible at the lateral side via the second opening and includes a second gloss unit value that is higher than the gloss unit value of the peripheral surface.