Ankle ROM is frequently reduced by injury or simple misuse/disuse. Have a look how the talus moves in the ankle mortise along with the other tarsal bones. MANUAL THERAPY: Talocrural and sub talar distraction techniques work well along with posterior (for dorsiflexion) and anterior (for plantar flexion) talus glides. TIP: Try combining inversion and eversion foot positions with distraction to focus on specific periarticular tissues. Is there a particular stretch/mobilisation technique which you h