Running shoe drop refers to the difference in height between the heel and the forefoot of a running shoe. It affects the angle of the foot while running and can impact biomechanics, foot strike pattern, and overall running experience. A higher drop means the heel is elevated more than the forefoot, creating a steeper slope. Conversely, a lower drop means the heel and forefoot are closer in height. The choice of drop depends on individual preferences, running style, and factors like cushioning, stability, and the desired feel of the flexible running shoes during the run.