Balance assessment method for human walking based on linear compass gait model

The purpose of this study is to verify the effectiveness of the balance map analysis in assessing the risk of fall while walking by analyzing the steady-state gait, the perturbed walking and the subsequent steps. The balance map visualizes three states as the region of stable touch down, the region of the risk of fall forward, and the region of the risk of fall backward, respectively. These regions are determined by ballistic trajectories of a linear compass gait model. The whole body movement during walking was measured by a motion capture. The state of contact between the foot and the ground was measured by foot sensors. The rope which equips with an auto-reel mechanism was attached on the ankle joints. The disturbance to prevent the swing leg from moving forward was induced by manual lock of released rope. The tension and the timing of disturbance were measured by a load cell. The results showed that the measured trajectories during the steady-state walking were within the region of stable touch down. When the disturbance was applied, the trajectory approached and went into the region of fall risk. The perturbed trajectory gradually converged to the steady-state gait by recovery steps. We also confirmed that the margin from the region of fall forward risk was after perturbation onset, and gradually increased by recovery steps. We conclude that the balance map analysis is effective for assessment of balance during walking.