Characteristics of center of body mass trajectory and lower extremity joint motion responded by dynamic motions of balance training system

PurposeTo provide an optimized strategy for balance rehabilitation training, we identified the change of joint angles in lower-extremity and trajectory of center of body mass (COM) in response to rotation of base plate of balance training equipment.MethodsFollowing Institutional Review Board approval, seven healthy participants with no sign of musculoskeletal pathology (gender: 7male, 25.5±1.7 years). Using customized balance rehabilitation training equipment, rotations were applied to participant’s standing. The participant’s four dynamic rotations induced by rotation of base plate were anterior-posterior (AP), right diagonal (RD), medialateral (ML), and left diagonal (LD). At the same time, by using an eight infrared camera-based three-dimensional motion capture system (T-10s; VICON Motion System Ltd., UK), the participant’s lower-extremity joint angles and COM trajectory were measured.ResultsWith the participant’s four dynamic rotation, AP and ML dynamic rotation of subjects showed high trajectory of COM deviation compared with another dynamic rotation (p<0.05). We also confirmed different changes of the joint angles in the lower extremity were induced overall (p<0.05).ConclusionsThese results indicate that optimizing the rotation of base plate for balance training, considering characteristics of changes of COM trajectory and joint angle, can lead to effective for improving balance ability in the elderly. However, additional tests with various speed and angular ranges of the base plate’s rotation are need to be conducted, as well as analysis of balance characteristics considering muscle activity, for a more accurate strategy of optimizing the rotation control of the base plate.