The effects of rocker sole and SACH heel on kinematics in gait.

The rocker sole and solid-ankle cushion-heel (SACH) heels are the most commonly prescribed external shoe modification. Only a limited number of scientific evidence exists to support these interventions in clinical practice. The objective of this study was to determine the effects of rocker soles and SACH heels on kinematics during gait. In this study, we investigated the gait parameters during level walking, stair climbing and stair descending in healthy volunteers and assessed the effects of the modified shoes on the motion of the forefoot and hindfoot compared with the traditional shoes. Eleven normal subjects participated in this study. A six-camera motion analysis system was used to capture motion trajectories. The three-dimensional (3D) coordinates of the markers were used to calculate the angles of flexion-extension, valgus-varus, and internal-external rotation at the hindfoot and forefoot joints in a gait cycle by the custom software for foot kinematic analysis. The results showed that the rocker soles offer several advantages from the viewpoint of gait kinematics. The forefoot joint excursion in sagittal plane while wearing rocker shoes was significantly less than that while wearing traditional shoes during level walking, stair climbing and stair descending. It means that they could mimic the action of the forefoot joint, aid in roll off, and simulate forefoot dorsiflexion. Since the bony structures mechanically link the forefoot joint and hindfoot joint to a triplanar axis of motion, they could be used whenever there is minimal or no motion at the forefoot joint or hindfoot joint, because of, for example, fusion, fracture, cast immobilization, orthosis design, pain, or arthritis.