Muscle quality will be calculated from the information of muscle strength and body composition (strength/lean muscle mass). The investigators will compute the joint torque during functional activates using biomechanical data from the 3-D motion analysis, whereas the lean skeletal muscle mass will be determined by the bioelectrical impedance analysis (BIA). Clinical and functional assessments for balance performance will also be conducted. Fracture and fall history prior to the testing will be recorded retrospectively.