Balance; Force sensor; Posture; Raster image; Stability; Stiffness Balancing; Biometrics; Computer vision; Convergence of numerical methods; Rasterization; Stiffness; Biometric informations; Direct measurement; Experimental validations; Force sensor; Human control strategies; Posture; Raster image; Vision based system; Robotics; adult; aged; ankle; Article; association; calibration; computer interface; control strategy; ground reaction force; high frequency oscillation; hip; human; human experiment; kinematics; middle aged; normal human; rigidity; rigidity analyzer; robotics; spine; standing; white noise; young adult; Young modulus