What type of glide of the calcaneus would improve pronation?

The medial glide of the calcaneus is correct for improving pronation because pronation involves the foot rolling inward and flattening of the arch during weight-bearing activities. When the calcaneus glides medially, it allows the subtalar joint to more effectively permit this inward motion. This movement aligns more with the natural mechanics of pronation, enabling the foot to absorb shock and adapt to uneven surfaces.

In contrast, lateral glides would promote an outward movement of the foot, which is associated with supination rather than pronation. Anterior and posterior glides are not directly related to the subtalar joint's pronation mechanics either and typically affect other motions or ranges of motion of the foot.

Therefore, the medial glide is essential in enhancing the capacity for the foot to pronate, as it directly facilitates the motions needed for this phase of gait and dynamic stability.